22q11.2 deletion syndrome a highly variable clinical syndrome caused by a contiguous deletion of 1.5 to 3 Mb in the long arm of one copy of chromosome 22 Project: NBS06 NOTE 1: The clinical manifestations of 22q11.2 deletion syndrome can include, but are not limited to, congenital abnormalities of the heart, thymus (leading to T-cell immunodeficiencies), palate, parathyroid and thyroid glands, learning disabilities, speech and developmental delay, and psychiatric problems; NOTE 2: The phenotype is variable and does not correlate with the size of the deletion; NOTE 3: Approximately 93% of cases are caused by a de novo deletion, and approximately 7% are inherited from a parent in an autosomal dominant manner; NOTE 4: DiGeorge syndrome, velocardiofacial syndrome, and conotruncal facial anomaly refer to clinical syndromes in which the majority of patients have been found to have a 22q11.2 deletion.
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3ʹ poly(A) tail a sequence of adenylyl residues at the 3ʹ end of eukaryotic messenger RNA Project: MM13 NOTE: Almost all mature eukaryotic messenger RNAs have 3ʹ poly(A) tails of 40 to 200 nucleotides, those of histones being a notable exception. The poly(A) tail is added enzymatically to the primary transcript, which is first cleaved 10 to 30 nucleotides past a highly conserved AAUAAA sequence. The poly(A) tail is then generated from ATP through the activity of polynucleotide adenylyltransferase. In practical terms, the poly(A) tail on messenger RNA has facilitated its ready isolation from total cellular RNA by affinity chromatography on oligo(dT) cellulose.
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3-amino-9-ethylcarbazole a soluble substrate for horseradish peroxidase that generates a colored, insoluble product Project: I/LA26 NOTE: It is often used in enzyme-linked immunospot assays, as well as Western blots.
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3-parameter display a graphic representation of data in which correlated values for three different parameters measured on the same cell are plotted Project: H43
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5ʹ cap a structural feature present at the 5ʹ end of most eukaryotic (cellular or viral) messenger RNA molecules and also some virion messenger RNA molecules, but not of bacterial messenger RNA molecules Project: MM13 NOTE: It consists of a residue of 7-methylguanosine and a triphosphate bridge linking it 5ʹ-5ʹ to the end of the polynucleotide chain. The cap structure is thought to protect the 5ʹ end of the messenger RNA from degradation by phosphatases or nucleases and to facilitate initiation of translation of messenger RNA by the eukaryotic (but not the bacterial) ribosome.
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5´ nuclease assay a method using a quenched fluorescently labeled probe that anneals to one strand of the polymerase chain reaction amplicon that is, in turn, cleaved during the extension phase of the polymerase chain reaction by the 5′ to 3′ exonuclease activity of many thermostable DNA polymerases Project: MM03 NOTE: The cleavage releases a fluorescent label from the 5′ end of such a probe. After many cycles, the level of fluorescence increases until it exceeds a background threshold and can be measured by a variety of instrumentation.
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5´ untranslated region a particular section of messenger RNA and the DNA that codes for it. It starts at the +1 position (where transcription begins) and ends just before the start codon (usually AUG) of the coding region. It usually contains a ribosome binding site Alternate Term: leader sequence
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5′-exonuclease assay (hydrolysis probe assay) a nucleic acid assay that uses the 5′ to 3′ exonuclease activity of Thermus aquaticus (Taq) polymerase to cleave a dual-labeled probe annealed to a target sequence during amplification Project: MM24 NOTE: The release of a fluorogenic tag from the 5′ end of the probe is proportional to the target sequence concentration.
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A260/A280 the ratio of the absorbance of a nucleic acid solution at a wavelength of 260 nm divided by the absorbance of the same solution at a wavelength of 280 nm Project: MM09, MM17 NOTE: Absorbance is a spectrophotometric method of assessing nucleic acid purity. DNA solutions with negligible contamination yield a ratio of ≥ 1.8, while RNA solutions with negligible contamination yield a ratio of ≥ 2.0.
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abnormal reference range a range of percentage of cells with an expected abnormal pattern among patients with a known clinical entity
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abnormality 1) an abnormal condition, state, or quality; irregularity; deviation; 2) In Hematology, a clinically significant alteration in the distribution of mature cell types, or the presence of immature or abnormal cell types at or above clinically significant levels or fractions Project: NRSCL8, H20
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absence of heterozygosity general term to describe the observation of an interval lacking heterozygosity. This observation may represent constitutional homozygosity (regions identical by descent or secondary to uniparental disomy) or a somatic mechanism (eg, deletion, mitotic recombination) Project: MM21
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absolute count a term used in hematology and molecular biology for the number of cells or sequence copies per unit volume of sample Project: NBS06 NOTE: The term “absolute” refers to the distinction from “relative count” and does not imply any specific level of standardization.
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absolute FTH measurement procedures rely on standard hormone solutions in buffer as calibrant, whose concentrations have been established gravimetrically or by other similar analytical means Project: C45 NOTE: Dialysis and ultrafiltration measurement procedures (whether direct or indirect) typically fall into this category, since such calibrants are normally used either to measure the free thyroid hormone concentration in the dialysate in the first case, or the total concentration in the sample in the second case.
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absolute relative difference absolute value of the difference between a measurement and a reference value, expressed in percent of the reference value (reference value must be different from 0) (see equation in POCT05) Project: POCT05
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absorb to take up or receive by chemical action; to take in and utilize Project: NRSCL8
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absorb to remove one reactant by the addition of another soluble reactant (neutralization), as the activity of an antibody may be neutralized by the addition of soluble antigen. See also adsorb
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absorbance 1) in optics, the capacity of a substance to absorb radiation; 2) decadic absorbance – the negative decadic logarithm of one minus the absorptance Project: VET04, VET03 NOTE 1: Absorbance is expressed as the logarithm of the reciprocal of the transmittance of the substance; A = log (1/T) = -log (T); NOTE 2: Formerly, the term “optical density” was used. The use of this term is discouraged.
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absorbance the logarithm of the ratio of radiant power (Io) incident on the sample to the radiant power (I) transmitted by the sample; A = log Io⁄I Project: H15, I/LA29 NOTE 1: Alternative terms sometimes used are “extinction” and “optical density”; NOTE 2: The wavelength at which the absorbance is measured can be shown as a superscript, the component of which the absorbance is measured as subscript, eg, A540HiCN = absorbance of hemiglobincyanide at 540 nm.
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absorptance the radiant power absorbed by a system Project: NRSCL8 NOTE: The power absorbed divided by incident radiant power; a = f abs / f0.
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absorption a process by which a substance is taken up chemically or physically in bulk by a material (absorbent) and held in pores or interstices in the interior Project: GP40, NRSCL8 NOTE: See also adsorption, sorption.
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absorption a taking in or reception by physicochemical action Project: NRSCL8
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absorptivity (molar extinction coefficient) a measure of the absorption of radiant energy having a given wavelength and/or frequency as it passes through a material of substance concentration of one mol/L Project: I/LA24
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absorptivity (absorption coefficient) a measure of the absorption of radiant energy (P) having a given wavelength and/or frequency as it passes through a material of substance concentration of one mol/L; P = Po · e- eb, where Po is the power of the incident light and b is the optical path length Project: NRSCL8
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accelerated stability testing a stability study designed to increase the rate of chemical or physical degradation of a product by using exaggerated environmental conditions (eg, light, temperature, humidity) Project: EP25, EP30 NOTE: Results from such studies may be used to compare the influence of product design/packaging factors or, in some cases, to estimate the expiry date when the product is handled under recommended storage conditions.
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acceptability based on individual criteria that set the minimum operational characteristics for a measurement procedure Project: EP10, PRE05, C62
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acceptable risk a state achieved in a measuring system in which all known potential events have a degree of likelihood for or a level of severity of an adverse outcome small enough such that, when balanced against all known benefits (whether perceived or real), patients, physicians, institutions, and society are willing to risk the consequences Project: EP23, GP47
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acceptance criteria a defined set of conditions that must be met to establish the performance of a system Project: AUTO13, MM21 NOTE: These conditions define the acceptability of the software from the user’s perspective.
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accepted reference value a value that serves as an agreed-upon reference for comparison, and which is derived as a) a theoretical or established value, based on scientific principles; b) an assigned or certified value, based on experimental work of some national or international organization; c) a consensus or certified value, based on collaborative experimental work under the auspices of a scientific or engineering group; or, when a), b), and c) are not available, the expectation of the (measurable) quantity, ie, the mean of a specified population of measurements (ISO 3534-2) Project: EP17, EP10, QMS24
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accepted reference value a value that is traceable to a standard of highest metrological order (eg, isotope dilution-gas chromatography/mass spectrometry) that serves as an agreed-upon reference for comparison and which is derived as a theoretical or established value based on scientific principles; an assigned value based on experimental work of some national or international organization; or a consensus value based on collaborative experimental work under the auspices of a scientific or engineering group (modified from ISO 5725-1) Project: POCT13
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access control protection of system resources against unauthorized access; a process by which use of system resources is regulated according to a security policy and is permitted by only authorized entities (users, programs, processes, or other systems) according to that policy (RFC 2828) Project: AUTO09
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access point a subsystem that consolidates data from one or more point-of-care devices onto another communication link Project: POCT01 NOTE: Examples of access points include a multiport concentrator or a dedicated single-port access point, typically connected to a local area network, or an access point that is part of a multifunctional device such as a patient monitor or personal computer.
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access point a piece of equipment that connects and merges data from one or more point-of-care testing devices into an interface or communication link to a network Project: POCT02 NOTE: Examples of access points include single- or multiple-port connection equipment, typically connected to a network (a local area network); or an access point can be part of more complex equipment, such as bedside patient monitors or personal desktop computers.
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access point a function or step in the operation of software that allows the “inputting” of information Project: AUTO13 NOTE: An access point can influence the behavior of the system.
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access point interface specifies the interface (principally input) to an access point or concentrator Project: POCT01 NOTE: This definition is equivalent to IEEE “bedside communication controller.”
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accession the steps required to ensure that a specific patient specimen and the accompanying documentation are unmistakably identified as referring to the same patient
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accession sequence of alphanumeric characters that uniquely identifies a specimen and the patient from whom it was derived in the information system that generates the sequence Alternate Term: case ID Project: AUTO14 NOTE: It is frequently referred to as the accession number or case number. A single patient might have many accession numbers associated with them, but an accession or case ID must only be associated with one patient at a single health care institution. Therefore, if a location prefix or site identifier is required to uniquely identify a specimen by its accession number within a multifacility health care system, the location prefix or site identifier is a required component of the accession or case ID.
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accessory article intended explicitly by its manufacturer to be used together with an IVD medical device to enable the IVD medical device to achieve its intended purpose or to augment or extend the capabilities of the IVD medical device in the fulfilment of its intended purpose (ISO 18113-1) Project: ISO 18113-1 NOTE: Adapted from §5.0, NOTE 3 of Global Harmonization Task Force (GHTF), Information Document 1206 Concerning the Definition of the 1207 Term ‘Medical Device,’ Final Document GHTF/SG1/N29R16:2005, May 20, 2005.
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accident an undesirable or unfortunate happening that occurs unintentionally Project: QMS11
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accompanying document document accompanying a medical device and containing information for those accountable for the installation, use, and maintenance of the medical device, the operator, or the user, particularly regarding safety (ISO 14971) Project: ISO 14971
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accreditation process by which a private, peer-level commission or association evaluates and ensures that a program of professional study or activity, such as laboratory testing, in an institution is meeting appropriate standards of organizational performance Project: POCT10
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accreditation process by which an authoritative organization gives formal recognition that an organization (eg, a laboratory) is competent to carry out specific tasks Project: QMS21, QMS25, QMS01, MM24, QMS17 Source: Quality Glossary
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accreditation procedure by which an authoritative organization gives formal recognition that an organization or person is competent to carry out specific tasks (modified from ISO/IEC 17000) Project: MM19, MM22
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accreditation body authoritative body that provides third-party attestation that a laboratory fulfills specified requirements and is competent to perform specific tasks NOTE: The authority of an accreditation body is typically derived from government.
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accreditation organization authoritative organization that provides attestation that a laboratory is competent to carry out specific analytical activities Project: QMS24
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accrediting agencies organizations that certify and/or monitor the quality activities of clinical laboratories (eg, the College of American Pathologists, The Joint Commission, World Health Organization, and the South African National Accreditation System) Project: MM14
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accuracy (of measurement) closeness of agreement between a measured quantity value and a true quantity value of a measurand (JCGM 200:2012) Alternate Term: accuracy of measurement; measurement accuracy Project: PRE04, ISO IEC Guide 99, H58, GP16, POCT05, I/LA20, C34, EP18, M55, POCT09, C43, M51, H26, NBS04, MM06, M24, I/LA28, GP34, H02, I/LA34, EP23, C58, MM19, NBS05, EP10, EP29, MM05, MM01, C56, EP31, EP27, MM20, MM14, EP09, EP26, C40, MM22, MM09, H60, EP14, C62, C57, MM03, MM23, POCT06, EP19, M52, C64, MM21, POCT14, H48, POCT04, QMS24, C24, NBS09, EP34, C63, C52, EP07, MM17, C49, POCT16, MM24, H62, NBS10, MM26, M67 NOTE 1: The concept “measurement accuracy” is not a quantity and is not given a numerical quantity value. A measurement is said to be more accurate when it offers a smaller measurement error (JCGM 200:2012); NOTE 2: The term “measurement accuracy” should not be used for “measurement trueness,” and the term “measurement precision” should not be used for “measurement accuracy,” which, however, is related to both these concepts (JCGM 200:2012); NOTE 3: “Measurement accuracy” is sometimes understood as closeness of agreement between measured quantity values that are being attributed to the measurand (JCGM 200:2012); NOTE 4: “Accepted reference value” may be used in place of “true value”; NOTE 5: “Measurement accuracy” is inversely related to “measurement error” and “measurement uncertainty,” and directly related to “measurement precision”; NOTE 6: In nucleic acid sequence analysis, the overall accuracy refers to the closeness of the agreement between a test result (ie, derived assembled sequence) and the accepted reference value (ie, true sequence); NOTE 7: Because M52 is a US-focused document, the term “analyte” is used instead of “measurand” throughout the document; NOTE 8: In microbiology, the ability of a microbial identification system to correctly identify the organism being tested; NOTE 9: For antimicrobial susceptibility testing, the agreement of the antimicrobial susceptibility testing system result with the result generated for the same isolate with the appropriate reference method; NOTE 10: In the case of total serum immunoglobulin E assays, the US IgE Standard and the international immunoglobulin E standard (11/234) are available for use as primary reference materials to promote trueness; NOTE 11: For immunoglobulin E antibody assays of defined allergen specificity, there are currently no universally accepted immunoglobulin E antibody standards with calibrated levels of allergen-specific immunoglobulin E. Heterologous interpolation of allergen-specific immunoglobulin E antibody results from a total immunoglobulin E dose response curve has become a universally accepted calibration method. Over the years, several research-based secondary immunoglobulin E antibody standards have been prepared with mass per volume unit estimates using antibody adsorption or depletion methods; NOTE 12: In drug testing, accuracy also refers to a test’s ability to detect a measurand when it is present at a concentration equal to or above a specified cutoff value; NOTE 13: Due to their inherent limitations, immunoassays are expected to produce some false-positive and false-negative screening results, thus definitive testing is warranted; NOTE 14: Temporal accuracy is the combination of point and trend accuracy; NOTE 15: In practice, an accepted reference value is substituted for the true value (ISO 3534-2); NOTE 16: Accuracy refers to a combination of trueness and precision (ISO 3534-2); NOTE 17: See trueness.
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accuracy closeness of agreement between a test result and the true value (ISO 5725-1) Project: C44, C37, H44, ISO 15198, GP40, AUTO08, EP21, EP17, EP46, QMS23, POCT15 NOTE 1: The term “accuracy,” when applied to a set of test results, involves a combination of random components (imprecision) and a common systematic error or bias component (modified from ISO 5725-1); NOTE 2: For oral anticoagulation monitoring systems, accuracy is measured by the extent to which measurements of blood samples from different patients agree with international normalized ratio values traceable to an International Reference Preparation (ISO 17593); NOTE 3: Usually expressed in the same units as the result, as the difference between the true value and the measured value, or as a percentage of the true value that the difference represents. Expressed this way, the quantity is more correctly termed “inaccuracy; NOTE 3: Accuracy of a measurement is defined as the closeness of agreement between a measured quantity value and a true quantity value of a measurand (JCGM 200:2012).
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accuracy (clinical or diagnostic) the qualitative or quantitative expression of a particular white blood cell differential finding in terms of sensitivity, specificity, efficiency, positive predictive value, and negative predictive value Project: H20 NOTE: It is the separate predictive value statements that are medically meaningful.
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accuracy the ability of a microbial identification system to correctly identify the organism being tested Project: M50
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accuracy (of measurement) closeness of agreement between a single test result and the accepted reference value (modified from ISO 5725-1) Project: POCT13, C48, POCT17
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accuracy (of measurement) closeness of agreement between a measurement result and the accepted reference value (ISO 17593) Project: ISO 17593 NOTE 1: The term "measurement accuracy," when applied to a set of test results, involves a combination of random components and a common systematic error or bias component (ISO 17593); NOTE 2: For oral-anticoagulation monitoring systems, accuracy is measured by the extent to which measurements of blood samples from different patients agree with INR values traceable to a thromboplastin International Reference Preparation (IRP).
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accuracy (of measurement) closeness of agreement between the result of a (single) measurement and a true value of the measurand (analyte) (modified from ISO 17511) Project: I/LA21, POCT10 NOTE: Accuracy is not a synonym for trueness, but is the combination of trueness and precision (modified from ISO 3534-2).
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accuracy 1) how close a test result for a specific analyte is to how much of the analyte is there; 2) the closeness of agreement between a test result and the accepted reference value (ISO 5725-1) Project: POCT08
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accuracy closeness of agreement between a measured quantity value and the true value of the quantity intended to be measured (modified from JCGM 200:2012) Project: I/LA26
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accuracy class class of measuring instruments or measuring systems that meet stated metrological requirements that are intended to keep measurement errors or instrumental measurement uncertainties within specified limits under specified operating conditions (JCGM 200:2012) Project: JCGM 200:2012 NOTE 1: An accuracy class is usually denoted by a number or symbol adopted by convention (JCGM 200:2012); NOTE 2: Accuracy class applies to material measures (JCGM 200:2012).
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acid fast descriptive term for bacteria that resist decolorization with acid-alcohol due to the presence of mycolic acids Project: M48
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acid α-glucosidase a lysosomal enzyme, encoded by the acid α-glucosidase gene that hydrolyzes terminal, nonreducing (1,4 and 1,6)-linked α-D-glucose residues with release of α-D-glucose Project: NBS07 NOTE 1: Also known as acid maltase; NOTE 2: Pompe disease is caused by a deficiency of this enzyme.
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acids chemicals with a pH lower than 7 Project: QMS04 NOTE: Acids can cause serious burns on human skin and many other materials.
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ACK 1) a data field name for a general acknowledgement message as specified in the HL7 protocol (HL7 V2.6); 2) a communication control character transmitted by a receiver as an affirmative response to a sender (ASTM) Project: AUTO01, AUTO02, AUTO03
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acquisition method method of analysis for the mass spectrometer to acquire data Project: NBS04, NBS09 NOTE: Three data acquisition methods are used in newborn screening: precursor ion scanning, selected reaction monitoring, and neutral loss scanning.
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acridinium ester compound that undergoes a light-emitting reaction in the presence of a dilute aqueous solution of sodium hydroxide and hydrogen peroxide; the amount of compound can be quantified by measuring the intensity of the emitted light or rate of photon emission Project: MM17 NOTE: The compound reacts with other substances containing primary and secondary aliphatic amines to yield chemiluminescent derivatives.
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actin See beta-actin (ACTB) gene Project: NBS06
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action personnel the personnel responsible for and having the authority and resources to lead or coordinate the implementation of a plan
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actionability the ability of the test result to modify patient management Project: MM26 NOTE: A variant is considered actionable if it is associated with a known targeted therapy, patient prognosis, or response to therapy.
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activated carbon porous carbon material used for removal of impurities Project: GP40 NOTE: See Subchapter 4.5 of CLSI GP40 for details.
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activated clotting time a coagulation test that is particularly sensitive to abnormalities in the intrinsic blood coagulation pathway and the anticoagulant activity of heparin Project: POCT14 NOTE: The activated clotting time is a measurement of the time in seconds required for a clot to form in a native (ie, nonanticoagulated) blood specimen that has been exposed to a contact activator of the intrinsic-phase blood coagulation pathway.
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activated partial thromboplastin time a coagulation test that measures the time, in seconds, needed for a fibrin clot to form in a plasma sample after appropriate amounts of calcium chloride and a partial thromboplastin reagent (phospholipid plus a contact activator) are mixed with the sample Project: POCT14, H21, H57 NOTE: The activated partial thromboplastin time measures the intrinsic and common coagulation pathways.
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activated partial thromboplastin time test a coagulation test that measures the time, in seconds, required for a fibrin clot to form in a sample after appropriate amounts of calcium chloride and a partial thromboplastin reagent (phospholipid plus contact activator) are mixed with the sample NOTE: Activated partial thromboplastin time measures the intrinsic and common coagulation pathways
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activation when referring to platelets, a series of processes and events that change a discoid platelet into a spiny, spiculated entity with extension of pseudopodia that results in the initiation of signal transduction Project: H58
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active error error by a front-line operator (ISO/TS 22367) Project: ISO/TS 22367
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active ingredient a component that is included in a chemical reagent or medium that has a pharmacological effect on microorganisms (eg, inhibitor, nutrient, preservative, or stabilizer) Project: M40
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active safety device a device requiring a user to take action to actively engage the safety feature to ensure its proper function Project: X03
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activity the capacity of a substance to react, corrected for the loss of reactivity due to the interaction of its constituents
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activity concentration of a radioactive material, the activity of the contained radionuclide to the volume of material Project: NRSCL8
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activity of a radioactive material the number of radioactive transitions taking place in a sample per unit time Project: I/LA23
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actor information systems or components of information systems that produce, manage, or act on information associated with operational activities in the enterprise
Project: AUTO16
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acute HIV infection the phase of infection that occurs between the time HIV is first detected by virological assay (eg, RNA, DNA, or viral antigens) until the first confirmed HIV-specific antibodies are detected. Project: M53
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acute phase reaction the physiological response to inflammation, injury, illness, or stress, in which a variety of plasma proteins become increased in concentration, or, in the case of some proteins, decreased in concentration Project: H60 NOTE: A subset of these proteins affects coagulation, eg, factor VIII, fibrinogen, and von Willebrand factor become elevated.
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acylcarnitine carnitine esters that are derived by conjugation of fatty acids and carnitine through the alcohol group and function as biomarkers for a number of inherited metabolic disorders (fatty acid oxidation disorders and organic acidemias) Project: NBS09, NBS04 NOTE 1: The fatty acid attached to carnitine reflects the composition of fatty acids within the mitochondria and is typically between two and 26 carbons, may be saturated or unsaturated, and may contain a hydroxyl or carboxylic acid group; NOTE 2: The elemental composition of the fatty acid is important in determining the mass of the acylcarnitine and, hence, its identification; NOTE 3: Throughout NBS04, the acylcarnitine species are referred to by their acyl chain carbon lengths (eg, octanoylcarnitine is referred to as “C8”); NOTE 4: Throughout NBS09, the acylcarnitine species are referred to by their acyl chain carbon lengths (eg, lignoceric acid is referred to as C24:0, and cerotic acid is referred to as C26:0); NOTE 5: See carnitine.
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adapter a short sequence of deoxynucleotides used to couple segments of oligonucleotide Alternate Term: oligonucleotide adapter Project: MM09
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addendum information added as an attachment or supplement to a document or record that expands or clarifies the original document or record Project: MM01, QMS26 Source: Quality Glossary NOTE: An addended report does not change the original test result(s) or diagnosis.
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addendum request for information adding to or clarifying the construction bidding documents Project: QMS04 NOTE: These are generally issued during the bidding phase as part of the construction contract documents.
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addendum ancillary report with additional information that expands or clarifies the original final diagnosis but does not change it Alternate Term: addenda Project: QMS12 EXAMPLE: Adding information derived from additional diagnostic studies, recuts from specimen blocks, consultations.
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additional service services of the architects and/or engineers that may be required for the project but were not originally specified in the contract NOTE: These would only be done with authorization from the owner.
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additive any ingredient that is placed in a collection container to facilitate an intended function (eg, to prevent the blood from clotting or to prevent glycolysis) Project: GP39, POL1/2, GP34, GP42 NOTE: Although the container closure is not considered an additive, it may contain or be coated with additives, which may come into contact with the specimen.
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adhesion the process by which platelets attach to surfaces or surface-bound proteins by certain glycoproteins, selectins, and integrins Project: H58
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adjunctive continuous glucose monitoring use of continuous glucose monitoring data to supplement, not substitute, self-monitoring blood glucose measurements in diabetes management Project: POCT05
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adjusted variance a statistical manipulation that adjusts the measured variance by subtracting components from other sources of variance Project: EP10 NOTE 1: For example, between-run variance is adjusted by subtracting the contribution from within-run variance; NOTE 2: Appendix C of CLSI EP10 describes a measurement procedure for determining adjusted variance.
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adjustment (of a measuring system) set of operations carried out on a measuring system so that it provides prescribed indications corresponding to given values of a quantity to be measured (JCGM 200:2012) Alternate Term: adjustment of a measuring system Project: JCGM 200:2012 NOTE 1: Types of adjustment of a measuring system include zero adjustment of a measuring system, offset adjustment, and span adjustment (sometimes called gainadjustment) (JCGM 200:2012); NOTE 2: Adjustment of a measuring system should not be confused with calibration, which is a prerequisite for adjustment (JCGM 200:2012); NOTE 3: After an adjustment of a measuring system, the measuring system must usually be recalibrated (JCGM 200:2012).
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adjuvant a substance admixed with an immunogen to elicit a more marked immune response Project: DI01, I/LA23
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administrative controls the implementation of management policies, work practices, and written procedures designed to reduce exposure of personnel to hazards (eg, written safety rules, safety training and competency assessment, specific work practices in procedure documents) Project: M29
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admission screening a screening specimen collected on admission to a special care baby unit (for all babies admitted from delivery or transfer) or within a short time after this admission and before the provision of treatments and interventions Project: NBS03
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adrenal insufficiency a condition in which the adrenal glands do not produce adequate amounts of steroid hormones, primarily cortisol, but possibly also aldosterone (a mineralocorticoid), which regulates sodium conservation, potassium secretion, and water retention Project: NBS09 NOTE: Because of the urinary losses of sodium, craving for salt or salty foods is common.
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adsorb to gather a gas, liquid, or dissolved substance on a surface in a condensed (usually monomolecular) layer NOTE: Materials such as plastic, glass, or particles (latex, bentonite, cellulose, etc.) are used for the removal of antibodies or antigens by immobilizing the appropriate reactant to the surface. Contrast with absorb.
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adsorption adherence of molecules, atoms, and ionized species of gas or liquid to the surface of another substance (solid or liquid) as the result of a variety of weak attractions that involve ionic, Van der Waals, and surface-active (hydrophobic/hydrophilic) forces Project: GP40 NOTE: See also absorption, sorption.
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adsorption a process by which a substance is bound at the surface of a material (adsorbent). See also absorption Project: NRSCL8
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ADT 1) an abbreviation for admission, discharge, or transfer; 2) a data field in a hospital information system denoting admission, discharge, or transfer Project: AUTO01, AUTO02, AUTO03
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adulterant a substance added to a specimen by a urine drug donor that will cause the specimen to test negative on initial screening Project: C52, C63 NOTE 1: Use of adulterants to avoid detection in forensic testing is considered even more serious than drug abuse itself; NOTE 2: In pain management, the use of an adulterant in the form of the drug prescribed (in order to test positive) is also an issue.
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Advanced Encryption Standard a future Federal Information Processing Standards publication being developed by the National Institute of Standards and Technology to succeed the Data Encryption Standard. It is intended to specify an unclassified, publicly disclosed, symmetric encryption algorithm, available royalty-free worldwide (RFC 2828) Project: AUTO09
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adventitious agent a contaminating agent–including bacteria, fungi, mycoplasma, endogenous and exogenous viruses–present in the inoculum or the substrate and/or materials used in the production of a biological product
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adverse event untoward incident, therapeutic misadventure, iatrogenic injury, or other adverse occurrence directly associated with care or services provided within the jurisdiction of a medical center, outpatient clinic, or other health care facility Project: POCT12 NOTE: Adverse events may result from acts of commission or omission (eg, administration of the wrong medication, failure to make a timely diagnosis or institute the appropriate therapeutic intervention, adverse reactions or negative outcomes of treatment) (see US Department of Veterans Affairs.)
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adverse event term for any event that is not consistent with the desired, normal, or usual operation of the organization Project: QMS11 Source: Quality Glossary
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adverse event term for any harmful medical event that is not consistent with the desired, normal, or usual operation of the product/device Project: EP19
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advisory notice communication issued by an organization, subsequent to delivery of a medical device, to provide supplementary information and/or to advise what action should be taken in
⎯ the use of a medical device
⎯ the modification of a medical device
⎯ the return of a medical device to its manufacturer
⎯ the destruction of a medical device (ISO 18113-1) Project: ISO 18113-1 NOTE: Issue of an advisory notice might be required to comply with national or regional regulations (ISO 18113-1).
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aerosol a system of respirable particles dispersed in a dust, gas, smoke, vapor, or fog that can be retained in the lungs (modified from ISO 15190) Project: M29 NOTE 1: Aerosol particles generally are ≤ 5 µm in size; NOTE 2: See droplet nuclei.
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aerosols system of particles dispersed in a gas, smoke, or fog (ISO 15190) Project: POL1/2, ISO 15190
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aerosols system of respirable particles dispersed in a dust, gas, smoke, vapor, or fog that can be retained in the lungs (modified from ISO 15190) Project: QMS04 NOTE: Aerosol particles range in size from 1 to 5 µm.
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aerotolerant describes a microorganism that grows in the presence of oxygen (may require carbon dioxide) Project: M56
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affinity in immunology, a measure of the attraction or force of association between a single antigenic site and a single antibody to that site Project: I/LA20, I/LA34 NOTE: Affinity is best measured using a monovalent antigen and a monovalent antibody fragment.
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affinity the force by which atoms, ions, molecules, prosthetic groups, and particles are attracted or held together in chemical compounds Project: NRSCL8, I/LA23
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affinity the force of attraction between molecules Project: I/LA30
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affinity in immunology, a measure of the attraction, or force of monovalent association, between a single antigenic determinant and a single antibody-binding site Project: I/LA28
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affinity chromatography a method for separating specific molecules from a heterogeneous mixture by capturing the molecule of interest (target) with a molecule for which the target has a high affinity or binding constant Alternate Term: purified chromatography Project: I/LA29 NOTE: The capture molecule is attached to a solid phase cross-linked dextran gel material.
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affinity constant in immunology, the equilibrium constant for the receptor + ligand reaction Project: I/LA18, LA01, DI01, I/LA28 NOTE 1: Strictly, the term only applies to homogeneous receptors and their ligands. However, polyclonal antibody preparations, which are heterogeneous in their affinity for homogeneous ligands, are often used; NOTE 2: The term also expresses the intrinsic binding strength of a receptor-ligand pair; NOTE 3: The average or mean affinity constants are usually described for polyclonal antisera because of their heterogeneity and polyvalency.
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affinity-independent assays an assay is affinity-independent whenever the product of Ka and Rf (molar concentration of binding sites) is greater than 10; when this occurs, the assay is considered to be in receptor excess
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agar a gelatin like material extracted from various red algae, used for solidifying certain media used for the culture of microorganisms and other purposes Project: POL1/2
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agar dilution susceptibility test an in vitro antimicrobial susceptibility test method conducted using serial concentrations of an antimicrobial agent incorporated into an agar growth medium in separate Petri plates that are inoculated with a bacterial suspension to determine the minimal inhibitory concentration Project: VET05, VET02
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agar dilution technique the method of antimicrobial susceptibility testing that is based on preparation of agar plates containing various concentrations of antimicrobial agents on which a defined inoculum of microorganisms is inoculated and then incubated and observed for growth Project: M43
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agar disk diffusion susceptibility test an in vitro antimicrobial susceptibility test conducted using disks impregnated with a specified single concentration of an antimicrobial agent applied to the surface of an agar medium that has been inoculated with the test organism Project: VET05, VET02 NOTE 1: The diameter of the zone of growth inhibition that results from the diffusion of an antimicrobial agent from the disks is measured with calipers or ruler and recorded in millimeters; NOTE 2: The diameter of the zone of growth inhibition that results from the diffusion of an antimicrobial agent from the disks is measured with calipers or a ruler and recorded in millimeters. Zone diameters are recorded and interpreted according to CLSI standards.
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agarose a carbohydrate material used for preparing gels for the electrophoresis step used in Southern blotting Project: MM02
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agent a substance or entity that causes a reaction or response. See specific modifier (eg, infectious agent or etiologic agent) Project: NRSCL8
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agglutination the aggregation of particulate matter as a result of antigen-antibody reaction Project: DI01 NOTES: a) Particles include bacteria, erythrocytes or other cells, or synthetic particles, such as plastic and/or glass beads coated with antigens or antibodies; b) Aggregation is usually primarily dependent on surface reactions mediated either by antigens or by antibodies that are physically or chemically attached to the particulate surfaces; agglutination or clumping of the particles follows as a secondary immune reaction.
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agglutination inhibition the process by which soluble antigen in the test medium reacts with soluble antibody, thereby inhibiting agglutination of indicator particles Project: DI01 NOTE 1: In agglutination inhibition assays, particle-bound and soluble antigen compete for soluble antibody; NOTE 2: With viral hemagglutination inhibition, host antibodies resulting from a specific infection are the most common forms of agglutination inhibition. In this case, viral-specific antibodies block the sites on the virus that agglutinate erythrocytes.
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agglutinin usually, an antibody that mediates the phenomenon of agglutination Project: DI01 NOTE 1: Agglutinins are present as isolated molecules in solution in serum, plasma, or other biological fluids being assayed, but they may first be attached (in reverse passive agglutination) or complexed to the particulate surface; NOTE 2: Some viruses (particularly the myxoviruses, such as influenza) agglutinate erythrocytes nonimmunochemically; hence, they are considered agglutinins, even though they are not antibodies.
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aggregation platelet clumping, largely mediated by fibrinogen or von Willebrand factor binding to the platelet receptor, GPIIb/IIIa (integrin αIIb β3), following activation of intact platelets by agonists or shear stress Project: H58
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agonist a substance or protein that can stimulate platelet activation (eg, collagen, adenosine diphosphate, epinephrine, thrombin, arachidonic acid, ristocetin) Project: H58
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agreement a contract, order, or understanding between two or more parties, such as between a laboratory and one of its vendors or customers Source: Quality Glossary
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agreement the proportion of specimens in which results obtained using a new test and those obtained using an imperfect standard agree; overall percent agreement, agreement of new test with imperfect standard-positive, and/or agreement of new test with imperfect standard-negative. The following terms relate to the term “agreement” in the context of this document: negative percent agreement – the proportion of nonreference standard negative samples in which the new test is negative; positive percent agreement – the proportion of nonreference standard positive samples in which the new test is positive; overall percent agreement – the proportion of samples in which the new test and the nonreference standard give the same outcome Project: MM10, I/LA33, MM24
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agreement the proportion of specimens for which results obtained using a candidate specimen type and those obtained using a primary specimen type agree Project: EP35
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agreement the proportion of specimens for which results obtained using a candidate examination and those obtained using comparative examination agree Project: EP12 NOTE 1: Agreement can also be measured within an examination using the same subject population but across two factors such as operators, sites, instruments, or reagent lots; NOTE 2: See negative percent agreement and positive percent agreement.
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aid in diagnosis as defined by the US Food and Drug Administration, an adjunct assay that is used in conjunction with clinical indications. The assay’s threshold value has been validated and device performance, such as negative predictive value, has been demonstrated. The assay’s relative sensitivity and specificity may or may not be established Project: H59
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air changes the amount of air it takes to replace existing air in a space over a specific time Project: QMS04
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air pressure the force exerted on a surface by the weight of air above it; more air is greater pressure, less air is lower pressure Project: QMS04 NOTE: Air pressure is used in heating, ventilation, and air conditioning to determine airflow from one area to another, as air moves naturally from areas of greater pressure to areas of lower pressure.
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airborne (transmission) occurs by dissemination of either airborne droplet nuclei or small particles in the respirable size range containing infectious agents that remain infectious over time and distance Project: M29
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airborne precautions applies to patients known or suspected to have serious illnesses transmitted by airborne droplet nuclei
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airborne transmission the spread of infection by inhalation of droplet nuclei or dust particles containing infectious agents
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alarm a signal intended to call the user’s attention to the presence of a potentially hazardous condition
Project: POCT05
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alarm threshold a glucose concentration or glucose concentration rate of change that initiates an alarm
Project: POCT05
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alert a communication that describes a problem, hazard, or risk that may exist with or may be associated with the use of a specific product which may have adverse health consequences Project: QMS10 NOTE 1: For the purpose of QMS10, the term Alerts is used to describe any form of communication from an external source. These may include alerts, field corrections, hazards, notifications, recalls (mandatory or voluntary), and/or withdrawals; NOTE 2: This communication is typically issued by the product manufacturer, but may be issued by a regulatory agency or an independent source.
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alert index indicates the lowest tested concentration of hemoglobin, bilirubin, and lipemia/turbidity at which the analyte concentration would be significantly falsely increased or decreased Project: C56 NOTE: This is also known as the threshold level.
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alert threshold a glucose concentration or glucose concentration rate of change that initiates an alert Project: POCT05
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alerts notifications that may appear to the users of a computerized physician or provider order entry system Project: GP49 NOTE 1: Some alerts are informational. For example, an alert may highlight a penicillin allergy when the provider is attempting to order penicillin or a similar drug. Some of the alerts may indicate deterrents to what is viewed as a best practice, but the provider has the ability to override the alert in the computer; NOTE 2: This type of clinical decision support tool has colloquially been termed a “soft stop”; NOTE 3: Examples include simple notification that a test has already been ordered or is expensive; the provider is then prompted to proceed or cancel the order.
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aleurioconidium (pl. aleurioconidia) a terminal or lateral conidium released by lysis or fracture of the supporting cell
Project: M54
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algorithm a set of rules for solving a problem in a finite number of steps, as for finding the greatest common divisor Project: M35, AUTO10
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algorithm a set of rules or calculations applied to test data that generate an interpretable or reportable result Project: MM17, I/LA28
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algorithm process or set of rules to be followed in calculations or other problem-solving operations Project: AUTO15 NOTE: Algorithms can perform calculation, data processing, and automated reasoning tasks.
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algorithmic testing recommended testing pathway in which the next step is based on a previous test’s result Project: GP49 NOTE 1: These pathways are usually more complicated than simple, single-step reflex testing; NOTE 2: Testing algorithms are commonly included in published documents or may less commonly occur automatically once the algorithmic cascade is ordered.
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alignment the process of lining up two or more sequences for the purpose of assessing the percent identity shared between sequences Project: MM09, MM18 NOTE 1: This assessment is made using pairwise or multiple-alignment algorithms; NOTE 2: Alignment algorithms can be global or local.
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aliquot in quantitative analysis, comprising a known fraction or measured portion of a whole and constituting a sample of the whole Project: NRSCL8 NOTE: Usually, the aliquot is expressed as a stated volume or mass, less often as the fraction of the whole.
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aliquot a portion of a larger whole (eg, a smaller sample acquired from a primary sample) Project: EP30 NOTE: The word “aliquot” is used to denote a smaller sample of a larger primary sample and is independent of the vessel type used for partitioning.
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aliquot in automation, a portion of a specimen placed in a separate container to facilitate concurrent testing or to hold in reserve for future use Project: AUTO01, AUTO07, AUTO02, QMS04, AUTO12 NOTE 1: The portion of the specimen is typically removed from the original specimen after initial processing, such as centrifugation, to obtain serum or plasma samples, and is considered to be chemically identical to all other subdivisions of an original sample of serum, plasma, urine, cerebral spinal fluid, etc.; NOTE 2: In all circumstances in which the aliquot may be removed from the system in which it is prepared and then handled or transported, it is necessary to identify the aliquot as an individual specimen distinct from the original specimen in a collection container labeled with a unique identifier that may be linked to or associated with the primary collection container.
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aliquot a portion of a specimen placed in a separate container to facilitate concurrent testing or to hold in reserve for future use Project: PRE04, AUTO14 NOTE 1: An aliquot removed from the primary (original) specimen container after initial processing, such as centrifugation, is considered chemically identical to all other subdivisions; NOTE 2: When a serum or plasma sample is analyzed, the aliquot may be a precisely measured volume or mass from which the measurand is quantified; NOTE 3: The portion of the specimen is typically removed from the original specimen after initial processing, such as centrifugation, to obtain serum or plasma samples, and is considered to be chemically identical to all other subdivisions of an original sample of serum, plasma, urine, and cerebrospinal fluid; NOTE 4: In all circumstances in which the aliquot may be removed from the system in which it is prepared and then handled or transported, it is necessary to identify the aliquot as an individual specimen distinct from the original specimen in a collection container labeled with a unique identifier that can be linked to or associated with the primary collection container.
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aliquot a portion of an original specimen collected by or submitted to a laboratory for testing Project: PRE05, C52, EP35 NOTE 1: Aliquots are removed from the specimen and tested, and aliquotting from a specimen needs to be done in a manner that preserves the integrity of the original specimen; NOTE 2: A sample is an aliquot of a specimen.
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aliquot container a container or tube that holds a portion or aliquot of a specimen Alternate Term: aliquot tube, daughter tube, derivative tube Project: AUTO12, AUTO14 NOTE: See aliquot.
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aliquot tube See aliquot container Project: AUTO12
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aliquotter part of an automation line where the samples are separated into one or more secondary tubes
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alkalis substances with a pH higher than 7 Project: QMS04 NOTE: Alkalis are also referred to as bases and can cause severe burns to the skin.
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all hazards planning detailed guidelines worked out in advance for addressing emergency situations Project: GP36 NOTE: All hazards planning, as used by emergency planners, promotes developing one general emergency operations plan intended to cover many different types of incidents. It relies on the core concept that many planned response actions are the same, irrespective of the type of disaster inciting them.
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allele 1) in genetics, any of several forms of a gene that is responsible for hereditary variation; 2) one of the alternate forms of a polymorphic DNA sequence that is not necessarily contained within a gene; 3) one of the alternative forms of a gene that may occupy a given locus Project: MM09, MM10, MM12, MM01, I/LA29, MM17 NOTE: A pseudoallele is an almost identical sequence to the allele found elsewhere in the genome.
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allele one of the alternative forms of a gene that may occupy a given locus Project: MM22, MM24 NOTE 1: In genetics, any of several forms of a gene that is responsible for hereditary variation; NOTE 2: One of the alternate forms of a polymorphic DNA sequence that is not necessarily contained within a gene.
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allele in genetics, any of several forms of a gene that is responsible for hereditary variation Project: MM03, NBS05 NOTE: A pseudoallele is an almost identical sequence to the allele found elsewhere in the genome.
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allele dropout occurs when a sample is genotyped and at least one allele is not present. This can occur due to amplification failure if the template DNA concentration is low or if a primer fails to bind due to a sequence change in the primer binding site. It can also occur if an allele falls outside of the defined size or range analysis of a particular allele (see National Forensic Science Technology Center) Project: MM01
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allele-specific oligonucleotide a nucleic acid probe of short length, exactly complementary to either the normal or one of the mutant sequences of a target gene region, most often used for the detection of point mutations Project: MM01, MM10, MM12 NOTE: An allele-specific oligonucleotide is a short sequence of DNA that is designed with 100% homology to a specific form of the gene but has noncomplementary nucleotides at the 3′ end to prevent polymerase chain reaction amplification of similar, but not identical, alleles.
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allele-specific polymerase chain reaction amplification of specific alleles, or DNA sequence variants, at the same locus. Specificity is achieved by designing one or both polymerase chain reaction primers so that they partially overlap the site of sequence difference between the amplified alleles
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allele-specific primer extension a solution-based, sequence-specific enzymatic reaction technology that can be used to assay multiple alleles in a single tube; an enzymatic DNA polymerization reaction that determines the genotype of a target Project: MM24
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allelic imbalance in a diploid organism with alleles A and B, when neither the A nor B allele frequency does not equal zero or the B allele frequency does not equal 50% Project: MM21 NOTE: Refers to the state in which one allele is present at a greater frequency than the other. This may be due to copy number changes or to absence of heterozygosity that is copy number neutral.
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allelic ratio the ratio of a specified allele to the total number of alleles, normally expressed as a fraction Project: MM17 NOTE 1: For example, if a specific allele represents 40% of the total alleles found at a given locus, the allelic ratio is 0.4; NOTE 2: Allelic ratio is synonymous with allele frequency.
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allergen an immunogen that when introduced into a host elicits the formation of immunoglobulin E antibodies Project: DI01, I/LA20, I/LA34 NOTE 1: To illustrate, the whole cat is not the allergen. Fel d 1 is an allergen produced by the cat, which is the allergen source or allergen carrier; NOTE 2: CLSI database I/LA37 contains a list of identified allergen specificities that are presented as allergen extracts (physiological extractions of biological source material that is complex in its protein, carbohydrate, and lipid composition) and individual native and recombinant allergen molecules that have been documented by studies involving human immunoglobulin E antibody binding.
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allergen extract a mixture of molecules, typically, proteins, glycoproteins, lipoproteins, or protein-conjugated chemicals/drugs that have been solubilized from a defined (usually biological) source and that a portion of which can elicit an immunoglobulin E antibody response in exposed persons Project: I/LA20, I/LA34 NOTE 1: In I/LA20, Appendix A contains a list of available allergen extracts; NOTE 2: Drugs tend to be single component allergenic sources; however, when in the presence of incipients, they can be viewed as a complex mixture of components; NOTE 3: CLSI database I/LA3720 contains a list of available allergen extracts. Allergen extracts have historically been referred to as “allergens” by diagnostic reagent manufacturers. This common practice should be replaced by the use of “allergen extract” to distinguish it from an allergen molecule.
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allergen molecule individual native or recombinant allergen that has unique molecular and structural properties, including a defined molecular weight, isoelectric point, carbohydrate composition, nucleotide and/or amino acid sequence, and reactivity to a monospecific or monoclonal antibody. In addition, the allergenic property of the “major allergens” of a given allergen specificity needs to be verified by its ability to bind to immunoglobulin E antibody and/or induce a positive skin test or histamine release from basophils from individuals who are clinically allergic to that allergen specificity Project: I/LA20 NOTE: CLSI database I/LA37 contains a list of available allergen molecules.
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allergen potency the composite concentration of all of the allergenic epitopes within an allergen that together produce a defined biological (type 1 hypersensitivity, immunoglobulin E-mediated) response in allergic persons Project: I/LA20, I/LA34
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allergen reagent the component of the immunoglobulin E antibody assay that contains allergen either bound to a solid phase (immobilized allergen) or in solution phase (liquid allergen, labeled or unlabeled) Project: I/LA34 NOTE: These reagents, like the allergen extracts from which they are derived, are typically composed of heterogeneous mixtures of proteins or chemicals/drugs that are conjugated on carrier proteins. More recently, purified components of native allergens or recombinant allergens have been successfully used. Ideally, the allergen reagent should contain all of the allergenic epitopes of that specificity that elicit immunoglobulin E antibodies in humans.
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allergen reagent the component of the immunoglobulin E (IgE) antibody assay reagent that contains allergen either bound to a solid phase (immobilized allergen, also called an allergosorbent) or in solution phase (liquid allergen, labeled or unlabeled) Project: I/LA20 NOTE: These reagents, when prepared with an allergen extract, are typically composed of heterogeneous mixtures of proteins or chemicals/drugs that are conjugated or bound to carrier proteins. More recently, purified allergen molecules representing native allergens or recombinant allergens have been successfully used in place of allergen extracts as the key assay reagent that defines the specificity of the analytical measurement. Ideally, the allergen reagent should contain all of the allergenic epitopes of that specificity that elicit IgE antibodies in humans.
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allergen source material the starting raw material from which allergenic extracts are obtained Project: I/LA20 NOTE: This material may or may not have been physically processed to remove extraneous, nonbiological materials, and it is typified by materials such as raw pollen, animal hair, mold cultures, drugs, venoms, foodstuffs, or recombinant expressed proteins.
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allergenic epitope a submolecular structure primarily responsible for immunoglobulin E antibody binding on the drug molecule Project: I/LA34
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allergenic epitope a submolecular structure or surface on the allergenic molecule primarily responsible for immunoglobulin E antibody binding Project: I/LA20
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allergenic molecule a single component (typically, a protein, glycoprotein, or lipoprotein) of a biological substance that is highly purified from extracts of native, biological material or produced by recombinant molecular biology techniques or other means for artificial epitope production methods Project: I/LA34
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allergenicity the ability of a biomolecule to elicit an immunoglobulin E antibody response in an immunocompetent host, which mediates type I hypersensitivity (allergic) reactions Project: I/LA34
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allergosorbent a solid phase material to which allergenic molecules are attached by covalent coupling methods or adsorption Project: I/LA20, I/LA34
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alloantibodies antibodies directed at epitopes that are present in some but not all members of the same species Project: I/LA29 NOTE: In the HLA setting, the antigens encoded by HLA genes are very polymorphic, with many variations of the genes found at the same loci. An individual can make an immune response against the epitopes that differ in another individual.
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alloantibody an antibody that reacts with an antigen from a genetically different individual of the same species. See also antiglobulin Project: NRSCL8
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alloantigen an antigen found in members of the same species Project: DI01
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allogeneic in immunology, cells, tissues, etc., that are related but sufficiently dissimilar in genotype to interact antigenically Project: DI01
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allogeneic denoting or relating to cells or tissues from individuals belonging to the same species but genetically dissimilar (hence, immunologically incompatible)
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alloimmunization the immunization of one animal with antigens from another of the same species Project: DI01
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allophycocyanin a fluorescent protein derived from cyanobacteria or red algae that is excited by a red (632 nm) laser (eg, HeNe) on many flow cytometers Project: I/LA26 NOTE: Allophycocyanin is excited maximally at approximately 650 nm with an emission maximum at 660 nm.
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allophycocyanin one of several phycobiliprotein-based fluorochromes, derived from algae or bacteria, which can be conjugated to antibodies for use in immunophenotyping Alternate Term: APC Project: H43, H42 NOTE: Allophycocyanin has a molecular weight of roughly 80 000 daltons. Although optimally excited at 655 nm, there is sufficient excitation at 635 nm to produce a useable signal at 660 nm when excited with a helium-neon or diode laser.
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allotype an antibody of a given class having certain molecular sites shared by only some members of a species and, therefore, acting as an antigen to other members of the same species
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allowable drift the maximum change in the quantity value by which product performance is kept within limits specified by the manufacturer Alternate Term: measurand drift Project: EP25
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allowable error limits symmetrical tolerance, plus and minus, around the target value for an analyte Project: EP23
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allowable total analytical error the amount of error in a measurement that can be tolerated without invalidating the medical usefulness of the result Project: EP26 NOTE 1: Allowable total analytical error is an analytical quality goal that sets a limit for both the imprecision (ie, random error) and bias (ie, systematic error) that are tolerable in a single measurement or single test result; NOTE 2: Allowable total analytical error excludes pre- and postexamination errors; NOTE 3: Such criteria are estimated from the influence of error in a test result on clinical outcome, from defined medical requirements, from biological variation, or from analytical capability; NOTE 4: In EP26, allowable total analytical error is abbreviated “TEa” (total error allowable); other publications might use “ATE” (allowable total error); NOTE 5: “Analytical performance specification” is another term used for the allowable total analytical error.
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allowable total error analytical quality goal that sets a limit for both the imprecision (random error) and bias (systematic error) that are tolerable in a single measurement or single test result Project: C24, EP07 NOTE 1: Such criteria are often provided by external quality assessment (proficiency testing) programs, government regulations, or based on biologic variation, or defined medical requirements; NOTE 2: For quality control planning, it is assumed there are no specimen-specific influences because they are a component of overall method performance that is not monitored by a statistical quality control strategy; NOTE 3: Some publications denote allowable total error as “ATE”; NOTE 4: Also called “total error allowable.”
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allowable total error the amount of error that can be tolerated without invalidating the medical usefulness of the analytical result Project: MM10, POCT14
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allowable total error an analytical quality goal or limit that sets a maximum for the combined effects of all error components (ie, inaccuracy) including both imprecision (random error) and all systematic effects (including bias) that are tolerable in a single measurement or single test result Project: EP10
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allowable total error quality goal or limit that sets a maximum for the combined effects of all error components (ie, inaccuracy), including imprecision (random error) and all systematic effects (including bias) that are tolerable in a single measurement or single test result Project: EP21, EP46
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allowable total error zone region on an error grid plot corresponding to measurement errors that are regarded as unlikely to cause patient harm Project: EP27
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alpha error probability of falsely rejecting the null hypothesis when it is true Alternate Term: type I error Project: EP07, EP31 NOTE: See confidence level.
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alpha globulin one of several groups of blood plasma proteins, divided into fractions, based on electrophoretic mobility somewhat slower than albumin Project: DI01
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alpha level the probability that one will reject the null hypothesis when it is true NOTE: The alpha level is often set at 5 or 1 percent.
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altered biological matrix milieu in which the analyte exists that has been modified or changed through additional processes not routinely conducted as part of the normal specimen collection process (eg, treatment with heat or sodium hydroxide, clarification of the specimen milieu by centrifugation) Project: EP39
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alternate care facility nonhospital facility that assumes the function of outpatient, urgent, or inpatient care during an emergency to promote expansion of community bed capacity and care Project: GP36
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alternate site testing sampling from anatomical sites other than the fingertip, ie, forearm, upper arm, thigh, calf, or palm, for blood glucose monitoring Project: POCT13
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alternative assessment (proficiency testing) a system for determining the reliability of tests for which formal proficiency testing programs are either not available or not appropriate, or when participation is not required by regulation. Appropriate alternative assessment procedures may include: participation in sample exchange with another laboratory performing a similar test; ungraded/educational challenges; split sample analysis with reference or other laboratories; split samples with an established in-house method; clinical validation by chart review; or other suitable and documented means. It is the responsibility of the laboratory director to define such alternative assessment procedures, as applicable, in accordance with good clinical and scientific laboratory practice Project: MM14
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alternative assessment system for determining the reliability of tests for which proficiency testing is either not available or not required, including ungraded and/or educational challenges; split sample analysis with reference or other laboratories; split samples with an established in-house method; assayed material; regional pools; clinical validation by chart review; or other suitable and documented means Project: QMS24 Source: Quality Glossary
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alternative hypothesis in interference testing, a statement to be tested at a specified power, that a substance causes interference greater than a specified limit (dalt)
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alternative pathway a series of complement interactions that is not activated by antigen-antibody complexes and does not involve complement components C1, C2, or C4 Project: DI01
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alveolar arterial oxygen tension difference [PO2 (A - aB)//PAO2 - PaO2 //(A - a) PO2// A - a DO2] the difference between the partial pressure of oxygen in alveolar gas compared to that of arterial blood (Cf. C12, C25). See also gas exchange indices Project: C25, C12
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alveolar oxygen tension (PO2 (A)//PAO2) the partial pressure of oxygen in alveolar gas Project: C12, C25 NOTE: Estimated by the standardized “alveolar air equation,” this quantity is required for calculation of gas exchange indices, such as the oxygen tension gradient and ratio, as well as being useful as an internal (within-sample) quality control check. See also gas exchange indices.
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amateur radio international hobby composed of volunteer operators, licensed (in the United States) under the Amateur Radio Service Project: GP36 NOTE 1: Amateur Radio Service is a communications service as defined by the Federal Communications Commission; NOTE 2: Also known as “ham radio”; NOTE 3: US and Canadian amateur operators often assist in emergencies, are usually organized through local clubs and organizations, and are often affiliated with the Amateur Radio Emergency Service.
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amended report change made to add or rephrase information, editorial changes, changes made to improve readability or clarity, or additional information that changes the final diagnosis or clarifies the original final diagnosis or interpretation Project: QMS26, QMS12 Source: Quality Glossary EXAMPLE: Amending a final surgical pathology diagnosis arising from a second review of the material.
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American Standard Code for Information Interchange (ASCII) a set of digital codes representing letters, numerals, and other symbols that is widely used as a standard format in the transfer of text between computers Alternate Term: ASCII Project: AUTO14 NOTE: ASCII is the required character representation to be used for CLSI AUTO14
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amino acid an organic compound containing two major functional groups: an amino group (−NH2) and a carboxylic group (−COOH) Project: NBS04 NOTE: Most physiologically important amino acids are those in which the amino group and the carboxylic acids are both attached to the carbon atom in position 2 (α carbon).
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amniotic fluid the fluid surrounding a fetus within the amnion Project: C58
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amount of substance the number of moles of the substance Project: NRSCL8
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amplicon the relatively low-molecular-weight products created from a target amplification reaction Alternate Term: amplification product Project: MM03, MM18, M55, MM19, MM22, MM24, NBS05 NOTE 1: Polymerase chain reactions produce double-stranded DNA amplicons. Nucleic acid sequence–based amplification or transcription-mediated amplification reactions produce primarily single-stranded RNA amplicons; NOTE 2: Amplicons are double-stranded DNA if created by polymerase chain reaction and are primarily single-stranded RNA if created in a nucleic acid sequence–based amplification or transcription-mediated amplification reaction.
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amplicon the product of polymerase chain reaction; a fragment of nucleic acid that has been synthesized using amplification techniques Project: NBS06, MM16, MM17, POCT15 NOTE: Amplicons will be double-stranded DNA if created by polymerase chain reaction and will be primarily single-stranded RNA if created in a nucleic acid sequence-based amplification or transcription-mediated amplification reaction.
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amplicons the DNA products of a polymerase chain reaction Project: MM05
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amplification the process of producing multiple copies of a specific segment of DNA, usually a gene, to obtain enough material for additional study Project: MM18, MM24, POCT15 NOTE: Polymerase chain reaction is a commonly used method of amplification.
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amplification the use of substances that directly increase signal in proportion to quantity of analyte, or directly increase the quantity of the analyte Project: I/LA18, MM10 NOTE: Examples include avidin biotin labels and substrates, which following hydrolysis by an enzyme label, produce fluorescent components.
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amplification the enzymatic replication in vitro of a target nucleic acid Project: MM12, MM01, MM22, MM09 NOTE: Polymerase chain reaction is a common method of nucleic acid amplification.
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amplification 1) the process of using substances that linearly increase signal in proportion to quantity of measurand; 2) logarithmic amplification – amplification with a response that is logarithmic rather than linear Project: MM05
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amplification product the relatively low molecular weight products created from a target amplification reaction Alternate Term: amplicon Project: MM10 NOTE: Amplicons will be double-stranded DNA if created by polymerase chain reaction and will be single-stranded RNA if created in a nucleic acid sequence-based amplification or transcription-mediated amplification reaction.
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amps short for amperes, which is a unit of measurement for electrical current Project: QMS04
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analysis the procedural steps performed that enable determination of the kind or the amount of an analyte in a specimen (ISO 15196) Project: ISO 15196
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analysis boundary dividing line (cursor) placed on a histogram or dual-parameter display that discriminates events that are considered positive or reactive with a particular antibody from those that are negative or nonreactive Project: H42, H43 NOTE: An analysis boundary is most commonly set on a histogram obtained using a negative control antibody so that a fixed small proportion of events is considered positive.
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analyte component represented in the name of a measurable quantity (ISO 17511) Project: ISO 17511, ISO 18153, EP06, EP10, MM07, EP15, I/LA23, I/LA25, I/LA24, MM14, HS02, MM13, MM10, MM03, POCT07, H59, I/LA28, MM12, MM16, POCT04, C49, I/LA21, C50, EP12, H58, POCT05, MM11, H57, MM17, C34, EP18, GP34, I/LA34, EP23, C58, MM19, NBS05, POCT10, MM01, C56, MM20, EP26, MM22, H60, C62, C57, MM23, POCT06, EP19, M52, C64, GP47, H48, QMS24, I/LA20, EP34, NBS09, EP07, EP31, NBS04, NBS07, C63, EP30, EP32, POCT16, MM24, EP39, H62, NBS10 NOTE 1: In the type of quantity “mass of protein in 24-hour urine,” “protein” is the analyte. In “amount of substance of glucose in plasma,” “glucose” is the analyte. In both cases, the long phrase represents the measurand (ISO 17511); NOTE 2: In the type of quantity “catalytic concentration of lactate dehydrogenase isoenzyme 1 in plasma,” “lactate dehydrogenase isoenzyme 1” is the analyte. The long first phrase designates the measurand (modified from ISO 18153); NOTE 3: The analyte is the particular component of interest to the patient; NOTE 4: This includes any element, ion, compound, substance, factor, infectious agent, cell, organelle, activity (enzymatic, hormonal, or immunological), or property, the presence or absence, concentration, activity, intensity, or other characteristics of which are to be determined; NOTE 5: As used in this document, the pure molecular or cellular form of the substance to be detected or quantified, independent of the sample matrix in which it is present; NOTE 6: The chemical entity or substance that is intended to be measured; NOTE 7: Formerly in CLSI EP10, analyte was used to describe both a single component (analyte) as well as the analyte in its specific matrix (measurand); NOTE 8: Also understood as the characteristic being measured in the test sample; NOTE 9: One or more systematic failure components may contribute to the bias; NOTE 10: Bias is a measure of the degree of trueness; NOTE 11: An estimate of bias is the average value of a series of measurements minus a reference value; NOTE 12: The analyte is the constituent or characteristic of the sample to be measured; NOTE 13: For the diagnostic allergy laboratory, allergen-specific immunoglobulin E molecules may be considered the primary analyte of interest; NOTE 14: In chemistry, “analyte,” or the name of a substance or compound, are terms sometimes used for “measurand.” This usage is erroneous because these terms do not refer to quantities (JCGM 200:2012); NOTE 15: For molecular genetic testing, the nucleic acid target to be detected, characterized, or measured; NOTE 16: In FISH analysis, the analyte could be viewed as the “genomic target” in “the number of genomic targets per cell” (eg, the number of BCR loci detected in a nucleus). It may also be viewed as the “genomic condition” in “the frequency of cells with a particular genomic condition” (eg, the frequency of cells with three BCR loci or the frequency of cells with juxtaposition of the BCR and ABL1 loci). Probe sensitivity and probe specificity are relevant to the first context, while analytical sensitivity and analytical specificity are relevant to the second context; NOTE 17: In microbiology, a substrate or antimicrobial agent being tested to determine microbial identification or antimicrobial susceptibility testing results, respectively; NOTE 18: For the purpose of NBS04 and NBS09, see biomarker; NOTE 19: A related term is measurand; NOTE 20: This is the chemical entity/substance that is actually intended to be measured; NOTE 21: In the measurand “mass of total protein in 24-hour urine,” “total protein” is the analyte (and “mass” is the property). In “amount of substance concentration of glucose in plasma,” “glucose” is the analyte (and “amount of substance concentration” is the property); NOTE 22: In the case of analyte-detection, qualitative examinations, an analyte is a unit that can be counted such as “copies of a specified bacterium” for which the specified bacterium is the analyte; NOTE 23: In “amount of glucose in plasma,” “glucose” is the analyte and the long phrase represents the measurand; NOTE 24: The term “analyte” must not be used for “measurand.”
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analyte constituent of a sample with a measurable property (ISO 18113-1) Project: ISO 18113-1, C24 EXAMPLE: In “mass of protein in 24-hour urine,” “protein” is the analyte and “mass” is the property. In “concentration of glucose in plasma,” “glucose” is the analyte and “concentration” is the property. In both cases, the full phrase represents the measurand (ISO 18113-1).
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analyte substance being measured or detected Project: POCT08, POCT15
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analyte a substance or constituent for which the laboratory conducts testing (US CFR 493; February 28, 1992) NOTE: This includes any element, ion, compound, substance, factor, infectious agent, cell, organelle, activity (enzymatic, hormonal, or immunological), or property, the presence or absence, concentration, activity, intensity, or other characteristics of which are to be determined.
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analyte-specific reagent antibodies, both polyclonal and monoclonal, specific receptor proteins, ligands, nucleic acid sequences, and similar reagents, which, through specific binding or chemical reaction with substances in a specimen, are intended for use in a diagnostic application for identification and quantification of an individual chemical substance or ligand in biological specimens (modified from 21 CFR §864.4020) Project: MM06
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analyte-specific reagents antibodies, both polyclonal and monoclonal, specific receptor proteins, ligands, nucleic acid sequences, and similar reagents which, through specific binding or chemical reaction with substances in a specimen, are intended for use in a diagnostic application for identification and quantification of an individual chemical substance or ligand in biological specimens (21 CFR 864.4020) Project: H43, I/LA28 NOTE 1: An analyte-specific reagent is the active ingredient of an in-house test; NOTE 2: Analyte-specific reagents can be viewed as having the following characteristics: used to detect a single ligand; no instructions or performance claims; and not promoted for use on specific instruments or in specific tests or test systems. The analyte-specific reagent rule was designed to accomplish several policy objectives, 1) ensuring the quality of materials used as components of in-house laboratory tests, 2) providing appropriate labeling so that health care users would understand the level of test validation. Analyte-specific reagents are intended to be unique reagents that are not marketed in a form that is combined with other reagents or support materials and have not been optimized to work on a proprietary or preoptimized analytical system (one in which the software and hardware has been specifically designed to allow for detection of signals generated by that reagent). Where reagents are marketed in this manner, the reagent is not considered an analyte-specific reagent but a part of a total test system and it should be submitted to an applicable regulatory agency for premarket review. Although it may be possible for an analyte-specific reagent to be used for purposes of allergen-specific immunoglobulin E testing, to date most if not all existing test systems are configured in such a manner that precludes use of analyte-specific reagents. Of note, use of analyte-specific reagents for testing of rare allergens is a particularly problematic practice because it is unlikely that most laboratories could assemble analytical and clinical materials needed to adequately validate such as assay. In contrast to an analyte-specific reagent, a “general purpose reagent” is “a chemical reagent that has general laboratory application, that is used to collect, prepare, and examine specimens from the human body for diagnostic purposes, and that is not labeled or otherwise intended for a specific diagnostic application.” Like analyte-specific reagents, general purpose reagents are not labeled for a specific clinical or diagnostic use. Because general purpose reagents are not analyte-specific, they should be able to be combined with, or used in conjunction with more than one analyte-specific reagent. In contrast, as stated above, an analyte-specific reagent is a specific chemical component, probe, or antibody that can detect an individual chemical substance or ligand. An analyte-specific reagent is considered the “active ingredient” or “building block” of a laboratory-developed test.
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analytical accuracy See accuracy Project: I/LA28
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analytical cross-reactivity evaluation of the level of nonspecific binding of control and/or test probes to nontargeted analytes that may be present in samples Project: MM16
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analytical interference systematic effect on a measurement caused by an influence quantity which does not by itself produce an indication, but which causes an enhancement or depression of the indication (ISO 15193) Project: ISO 15193
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analytical measurement range the range of analyte values that a method can directly measure on the sample without any dilution, concentration, or other pretreatment that is not part of the typical assay process Project: H57, POCT09, EP31 NOTE: See measuring interval.
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analytical measurement range range of analyte values that a method can directly measure on the specimen without any dilution, concentration, or other pretreatment, not part of the usual assay procedure Project: C50, MM06, AUTO15 NOTE: See measuring interval.
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analytical measuring interval set of values of quantities of the same kind that can be measured by a given measuring instrument or measuring system with specified instrumental measurement uncertainty, under defined conditions (JCGM 200:2012) Alternate Term: working interval; measuring range; measuring interval; measurement interval Project: I/LA21, ISO 18113-1, H26, POCT07, MM06, EP06, C51, EP17, C56, MM14, EP09, EP26, H60, VET04, C62, EP05, EP15, C57, MM03, MM23, POCT06, EP21, EP46, C24, EP34, C63, MM17, C34, C62, GP26, H26, EP39, EP35, NBS10 NOTE 1: In some fields, the term is “analytical measurement range,” “measuring range,” or “measurement range” (modified from JCGM 200:2012); NOTE 2: The lower limit of a measuring interval should not be confused with “detection limit” (JCGM 200:2012); NOTE 3: This represents the interval of in vitro diagnostic examination results over which the performance characteristics of the in vitro diagnostic medical device were validated by the manufacturer; NOTE 4: Formerly, the terms “reportable range” or “measuring range” were used in CLSI documents; NOTE 5: The measuring interval over which the performance characteristics of an in vitro diagnostic medical device have been validated has been called the reportable range (ISO 18113-1); NOTE 6: For a discussion of the difference between interval and range, see A.2.11 (ISO 18113-1); NOTE 7: In the United States, the term often used is “analytical measuring range”; NOTE 8: In laboratory medicine, the term is defined as “measuring range,” or “analytical measurement range”; NOTE 9: The measuring interval is intended to refer to the interval of values that a measurement procedure can directly measure on the sample without any dilution, concentration, or other pretreatment not part of the usual measurement process; NOTE 10: The measuring interval has been called the analytical measurement range, reportable range, analytical range, and calibration range; NOTE 11: For EP05, the range of values (in units appropriate for the measurand) over which the acceptability criteria for the measurement procedure have been met; ie, the intersection of the linearity interval, the interval limited by the lower and upper limits of quantitation, and the interval representing acceptable imprecision; NOTE 12: The interval (or range) of values (in units appropriate for the analyte [measurand]) over which the acceptability criteria for the measurement procedure have been met; that is, where errors due to nonlinearity, imprecision, or other sources are within defined limits; NOTE 13: Formerly, the term “reportable range” was used in EP15, and another commonly used term is “analytical measurement range”; NOTE 14: The concentration range of results for which the measurement procedure functions to meet its intended use; NOTE 15: Measuring interval is determined by linearity, accuracy, and limit of detection; NOTE 16: The analytical measuring interval is the concentration value interval within which a given accuracy is achieved and a linear relationship between measurand values and the measurement procedure’s results is maintained with no preexamination dilution, concentration, or other pretreatment not part of the standard or routine measurement; NOTE 17: Although the terms “analytical measuring range” and “working interval” are commonly used instead of “analytical measuring interval,” their use is not encouraged; NOTE 18: This interval is separate from the extended measuring interval, within which preexamination dilutions are needed to obtain results; NOTE 19: It is sometimes called “analytical measurement range” or “measurement range,” which is the range of analyte values that a method can directly measure on the specimen without any dilution, concentration, or other pretreatment not part of the usual assay process; NOTE 20: The ability of a measurement procedure to detect small quantities of the analyte; NOTE 21: Analytical sensitivity is usually expressed as the “minimum detectable concentration” or “detection limit.”
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analytical method See and use measurement procedure Project: I/LA21, I/LA23
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analytical performance the sum of all analytical attributes that might be important for a test method for which the measurand is used for a specific intended use Project: EP19 NOTE: Performance characteristics usually include detection capability, specificity, and other parameters.
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analytical performance goal the analytical performance (ie, bias, imprecision, nonspecificity) of an assay desired for a particular clinical application (ISO 15196) Project: ISO 15196
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analytical phase laboratory activities including specimen processing, reagent preparation, and specimen analysis Project: NBS04, NBS09
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analytical portion portion of material taken from the analytical sample and on which the measurement is actually carried out, either directly or following dissolution (ISO 15193) Project: ISO 15193 NOTE: The analytical portion is taken directly from the primary sample or laboratory sample if no preparation of these is required. The analytical portion is sometimes dissolved to give an analytical solution before being exposed to themeasuring device (ISO 15193).
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analytical process the technical process including the operation of equipment and the performance of the defined steps of a testing procedure designed to produce data including the examination of patient samples Project: POCT10
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analytical reactivity the capacity of an assay to detect several strains or serovars of a species, several species of a genus, or a similar grouping of closely related organisms or antibodies (Jacobson et al. Manual of Diagnostic Tests and Vaccines for Terrestrial Animals 2017) Alternate Term: inclusivity Project: MM17
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analytical result in EP06, the final result of a measurement on a test specimen NOTE: The result is usually in concentration or activity units; it is assumed that the measurement procedures to be evaluated by the procedures in EP06 are quantitative methods that yield a numerical output.
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analytical run a set of specimens that are analyzed in a time period within which the measurement system is considered to have stable trueness and precision Project: C50, NBS04, NBS09 NOTE: An analytical run usually consists of both quality control specimens and patient specimens. NOTE 2: An analytical run is sometimes referred to as “batch analysis.”
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analytical sample sample prepared from the laboratory sample and from which analytical portions can be taken (ISO 15193) Project: ISO 15193 NOTE: The analytical sample can be subjected to various treatments before an analytical portion is taken (ISO 15193).
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analytical sensitivity quotient of the change in an indication and the corresponding change in the value of a quantity being measured (ISO 15193) Project: MM09, ISO 15193, M55, M53, MM19, MM20, MM14, MM07, MM22, MM03, MM21, POCT17, I/LA20, NBS09, C63, MM17, NBS05, MM24, NBS10 NOTE 1: The term “analytical sensitivity” is not intended to be used as a synonym for “detection limit” (ISO 15193); NOTE 2: ISO/IEC Guide 99:2007 uses the term “sensitivity of a measuring system” (ISO 15193); NOTE 3: The amount of measurand being detected by the measurement procedure at a given detection frequency; NOTE 4: See seroconversion sensitivity; NOTE 5: Sensitivity may depend on the value of the stimulus; NOTE 6: Sensitivity depends on the imprecision of the measurements of the sample; NOTE 7: The analytical sensitivity of a measuring system is the slope of the calibration curve; NOTE 8: Analytical sensitivity should not be used to mean detection limit or quantitation limit, and should not be confused with diagnostic sensitivity (modified from ISO 18113-1); NOTE 9: In qualitative testing, analytical sensitivity is defined as the test method’s ability to obtain positive results in concordance with the positive results obtained by the reference method; NOTE 10: In FISH analysis, analytical sensitivity is most often used to describe the lowest frequency of cells with a particular abnormal genomic composition that can be detected by the FISH assay. In this context, analytical sensitivity is equivalent to the limit of detection; NOTE 11: For the purposes of microbial detection, analytical sensitivity is equivalent to limit of detection; NOTE 12: The sensitivity depends on the imprecision of the assay; NOTE 13: If the true sensitivity of a device is better than the reference method, its apparent specificity will be less and the level of apparent false-positive results will be greater; NOTE 14: In genotyping or DNA sequencing, the limit of detection is the lowest concentration of the target nucleic acid that can be reproducibly measured which exceeds the blank sample with no analyte. It may be below the linear range of the assay; NOTE 15: The analytical sensitivity of an assay that detects somatic mutations depends directly on both the number/percentage of nucleated tumor cells in the specimen to be tested and the number/percentage of tumor cells with mutations; NOTE 16: The analytical sensitivity of a solid tumor assay also relates to the lowest percentage of nucleated tumor cells that would be suitable for obtaining reliable results; NOTE 17: The term “analytical sensitivity” has been historically used to describe the lowest amount of a given substance in a biological specimen that is detectable in an assay system; NOTE 18: Throughout I/LA20, the lower limit of quantitation and not “analytical sensitivity” is used to indicate the lowest amount of total or allergen-specific immunoglobulin E antibody in a sample that can be detected by immunoassay with a stated probability and defined accuracy. See lower limit of quantitation; NOTE 19: The ability of a measurement procedure to detect small quantities of the analyte; NOTE 20: In the context of NBS09, sensitivity refers to the signal intensity of the analyte being measured; NOTE 21: The ability of a measurement procedure to detect small quantities of the analyte; NOTE 22: Analytical sensitivity is usually expressed as the “minimum detectable concentration” or “detection limit”; NOTE 23: The sensitivity may depend on the value of the stimulus; NOTE 24: The sensitivity depends on the imprecision of the measurements of the sample.
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analytical sensitivity in quantitative testing, the change in response of a measuring system or instrument divided by the corresponding change in the stimulus Project: MM06 NOTE 1: The sensitivity may depend on the value of the stimulus; NOTE 2: The sensitivity depends on the imprecision of the measurements of the sample; NOTE 3: If the true sensitivity of a device is better than the reference method, its apparent specificity will be less and the level of apparent false-positive results could be greater.
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analytical sensitivity quotient of the change in a measurement indication and the corresponding change in a value of the quantity being measured (modified from JCGM 200:2012) Project: EP17 NOTE 1: VIM uses the term “sensitivity of a measuring system”; NOTE 2: The analytical sensitivity of a measuring system is the slope of the calibration curve; NOTE 3: Analytical sensitivity should not be used to mean detection limit or quantitation limit, and should not be confused with diagnostic sensitivity (modified from ISO 18113-1).
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analytical sensitivity the proportion of biological samples that have a positive test result or known variant and are correctly classified as positive Project: MM26 NOTE 1: The overall analytical sensitivity is a measure related to the final assembled sequence; NOTE 2: For nucleic acid sequencing, it is sometimes used to refer to the detection limit.
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analytical sensitivity the ability to obtain positive results in concordance with the reference method. Analytical sensitivity describes the ability to detect very low concentrations of a given substance in a biological specimen and is often referred to as the limit of detection Project: MM01
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analytical solution solution prepared prior to measurement by dissolving an analytical portion in a liquid or solid material, with or without reaction (ISO 15193) Project: ISO 15193
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analytical specificity ability of a measurement procedure to determine solely the quantity it purports to measure (ISO 15193) Project: ISO 15193, MM01, MM20, MM07, MM22, MM21, POCT17, I/LA20, NBS09, MM17, EP39, NBS10 NOTE 1: The ability of a measurement procedure to measure solely the measurand (ISO 17511); NOTE 2: The ability of a measurement procedure to distinguish the target sequence(s)/allele/mutation(s) from other sequences/alleles in the specimen/genome; NOTE 3: Specificity of a measurement procedure should not be confused with diagnostic specificity; NOTE 4: Specificity is the ability of an analytical method to determine only the component it purports to measure; the extent to which the assay responds only to (all subsets of) a specified analyte and not to other substances present in the sample; NOTE 5: Analytical specificity refers in general to the ability of an assay to measure one particular substance, rather than others, in a sample. Applied to immunoglobulin E assays with single allergens, “one particular substance” would indicate the repertoire of allergen-specific immunoglobulin E to “one particular allergen molecule”; NOTE 6: In the previous editions of I/LA20, analytical specificity of immunoglobulin E–detecting assays was solely linked to the capability to selectively measure immunoglobulin E, instead of other immunoglobulin classes or subclasses (eg, immunoglobulin G, immunoglobulin M). This definition refers to the “antibody-related analytical specificity (selectivity)” of immunoglobulin E–detecting assays and is still an important definition for modern immunoassays; NOTE 7: Allergen molecules for quantifying allergen-specific immunoglobulin E will limit the detected immunoglobulin E repertoire. Only antibodies binding to the selected molecule (eg, major cat allergen Fel d 1) will be detected instead of all allergen source-specific (eg, cat-specific) antibodies. Thus, the use of allergen molecules increases analytical specificity compared to the broad allergen-specific immunoglobulin E repertoire directed toward a complex mixture of proteins in an extract (eg, from cat dander). This new definition refers to the “allergen-related analytical specificity (selectivity)” of immunoglobulin E–detecting assays; NOTE 8: The term “allergen-related analytical specificity (selectivity)” is particularly useful to understand and justify the concept of species-specific vs crossreactive immunoglobulin E antibodies toward defined allergen molecules. In case of particular physicochemical properties of certain allergen molecules (eg, high pH and digestion stability, high abundance in an allergen source), immunoglobulin E detection with these molecules might be helpful to identify risk-associated allergen-specific immunoglobulin E responses; NOTE 9: The ability of a measurement procedure to determine specifically the concentration of the target analyte in the presence of potentially interfering substances or factors in the sample matrix.
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analytical specificity ability of a test method to measure solely the measurand (ISO 17511) Project: EP19 NOTE: Specificity has no numerical value in this context.
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analytical specificity ability of a measurement procedure to measure solely the measurand (ISO 17511) Project: ISO 17511, H44, H56, I/LA21, C50, GP16, M55, I/LA28, M53, MM19, H60, C63, H62 NOTE 1: Lack of specificity may be called analytical interference; NOTE 2: A type of interference in immunochemistry measurement procedures may be cross-reactivity; NOTE 3: Analytical specificity (selectivity) of a measurement procedure should not be confused with diagnostic specificity; NOTE 4: Analytical specificity (selectivity) is the ability of an analytical method to determine only the component it purports to measure; the extent to which the assay responds only to (all subsets of) a specified measurand (analyte) and not to other substances present in the sample; NOTE 5: Within the context of this guideline, specificity refers to an assay that is specific for immunoglobulin E and shows no cross-reactivity of the antihuman immunoglobulin E reagent with other classes of human antibodies (eg, immunoglobulin G, immunoglobulin A, immunoglobulin M, and immunoglobulin D). Tests of reagent specificity shall demonstrate that the antibody being measured is immunoglobulin E and that it is specific for the allergen of interest based on soluble allergen inhibition studies. The specific immunoglobulin E assay system should be tested for interfering substances, including but not limited to, lipids, hemoglobin, and medications commonly used by allergic patients, and any known interference should be identified in the manufacturer’s product literature; NOTE 6: In quantitative testing, the ability of a measurement procedure to determine only the component it purports to measure or the extent to which the assay responds only to all subsets of a specified measurand (analyte) and not to other substances present in the sample; NOTE 7: For qualitative or semiquantitative assays, it is the method’s ability to obtain negative results in concordance with negative results obtained by the reference or comparative method; NOTE 8: In Immunology, specificity is an antiserum quality defining its reactivity with defined antigens and lack of specificity is the inaccuracy introduced by cross-reacting and/or interfering substances, because cross-reacting substances compete with the analyte for antibody-binding sites; NOTE 9: Analytical specificity of an immunohistochemical assay is largely dependent on the characteristics of the primary antibody in the total test system; NOTE 10: It denotes freedom from interference by any element or compound other than the analyte; NOTE 11: Specificity has no numerical value in this context; NOTE 12: “Analytical specificity” is an older term; historically, the preferred term is “selectivity”; NOTE 13: For assays that rely on antibody-based detection systems, specificity is an antibody (or antiserum) quality defining its reactivity with defined antigens, and lack of specificity is the inaccuracy introduced by cross-reacting and/or interfering substances, because cross-reacting substances compete with the analyte for antibody-binding sites; NOTE 14: Analytical specificity (selectivity) of a measurement procedure should not be confused with clinical specificity; NOTE 15: See selectivity.
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analytical specificity ability of a measurement procedure to determine solely the measurable quantity it purports to measure (modified from ISO 17511) Project: I/LA21, I/LA23, MM10, I/LA02, MM12, I/LA29, MM24 NOTE: The ability of a measurement procedure to distinguish the target sequence(s) or allele or mutation(s) from other sequences/alleles in the sample or genome.
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analytical specificity in quantitative testing, the ability of a measurement procedure to determine only the component it purports to measure or the extent to which the assay responds only to all subsets of a specified analyte (measurand) and not to other substances present in the sample; for qualitative or semiquantitative tests, the method’s ability to obtain negative results in concordance with negative results obtained by the reference method; in Immunology, specificity is an antiserum quality defining its reactivity with defined antigens and lack of specificity is the inaccuracy introduced by cross-reacting and/or interfering substances, because cross-reacting substances compete with the analyte for antibody-binding sites Project: MM03, H20, MM06 NOTE: For qualitative or semiquantitative tests, analytical specificity is defined as the method’s ability to obtain negative results in concordance with negative results obtained by the reference method.
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analytical specificity the ability of a test to distinguish target sequences, alleles, or variants from other sequences or alleles in the specimen or genome being analyzed Project: MM09, MM26 NOTE 1: For nucleic acid sequencing, “analytical specificity” refers to the test’s ability to differentiate the target sequence from other sequences that may be present (eg, pseudogenes); NOTE 2: Overall analytical specificity is measured relative to the final assembled sequence.
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analytical validation assessment of performance characteristics of an assay, including accuracy, precision, specificity, limits of detection and quantitation, linearity and range, ruggedness, and robustness
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Analytical Work Order Step a unit of work allocated from a work order, assigned to an analyzer, performed on a biological specimen, and producing observations characterizing this specimen Project: AUTO16
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analyzer an instrument and/or specimen processing and handling device that performs measurements on patient specimens of quantitative, clinically relevant analytes Project: AUTO01, EP12, AUTO02, POCT04 NOTE: A portion of a patient's specimen is consumed in the analytic process.
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analyzer manager a key Laboratory Analytical Workflow Profile actor that organizes and distributes workload across connected laboratory instruments and similar devices Project: AUTO16 NOTE: Typically, the analyzer manager is a source for orders and patient specimen information. Examples of analyzer managers are laboratory information and middleware systems
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anatomy study of the structure of an organism Project: GP48 NOTE: In humans, anatomy is the study of structure and function of the body.
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ancillary a secondary or subsidiary action (eg, testing) or location (eg, site) Project: POCT04
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angle of insertion the angle formed by the surface of the skin and the needle entering the skin Project: PRE02
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anion resin an ion-exchange resin with immobilized positively charged exchange sites, which can bind negatively charged ionized species Project: GP40
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annealing the hybridization of two complementary strands of nucleic acid, as in the hybridization of a probe or primer with the target DNA Project: MM01, MM02, MM10, MM12, MM22, MM24
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annotation process of assigning functional information such as sequence conservation and predicting the effect of a variant on protein structure and function to DNA variants Project: MM26 NOTE 1: Based on known information regarding functionality, pathogenicity, or actionability, variants can be evaluated that contribute to classification; NOTE 2: The tasks of variant annotation, evaluation, classification, and interpretation are usually performed by variant analysts or scientists.
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anode a positively charged conductor by which electrons leave an electrical device Project: GP28
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ANSI acronym for American National Standards Institute (www.ansi.org) Project: AUTO01, AUTO07, AUTO02, POCT01, POCT02, AUTO03 NOTE: In Automation, the Microsoft Windows American National Standards Institute character set is composed of International Organization for Standardization (ISO) 8859/x plus additional characters.
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antecubital situated anterior to the cubitis, or elbow (Dorland's Illustrated Medical Dictionary. 33rd ed. Elsevier, Inc.; 2019) Project: PRE02
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antecubital fossa area of the arm anterior and below the bend of the elbow where major veins for venipuncture are located Project: GP48
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anteroom small room placed between two rooms or spaces that acts as an air lock or transition space between two areas of differential air pressure to reduce contaminated air from escaping one area and going into the other Project: QMS04
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antianimal antibodies antibodies that show strong avidity for test antibodies of one species, but the antibody may cross-react with immunoglobulins from other species Project: I/LA30
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antibiogram overall profile of antimicrobial susceptibility testing results of a microbial species to a battery of antimicrobial agents. For the purpose of CLSI document M39, see cumulative antimicrobial susceptibility test data summary Project: M38, M27, M44, M52, M11
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antibiogram the report generated by analysis of antimicrobial susceptibility test results (usually from a single health care facility) from a defined period of time that reflects the percentage of first isolates (per patient) of a given species or organism group that is susceptible to each of the antimicrobial agents routinely tested Project: M39
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antibody 1) any of numerous Y-shaped protein molecules produced by B cells as an acquired primary immune defense following antigen exposure, each molecule having a unique binding site (either 2 for immunoglobulin G, immunoglobulin A, immunoglobulin D, and immunoglobulin E, or 10 for immunoglobulin M) that can combine with the complementary site of an antigen thereby potentially signaling other immune defenses; 2) the functional component of antiserum, often referred to collectively as a population of molecules, each member of which is capable of reacting with (binding to) a specific antigenic determinant Project: NRSCL8, I/LA34 NOTE 1: An antibody molecule is, by definition, monospecific, but it might also be idiospecific, heterospecific, polyspecific, or of unwanted specificity. It cannot be nonspecific, except in the sense of nonimmunochemical binding; NOTE 2: These proteins are immunoglobulins and bind by means of specific binding sites to a specific antigenic determinant.
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antibody specific immunoglobulin formed by B-lymphocytes in response to exposure to an immunogenic substance and able to bind to this (ISO 19001) Project: ISO 19001, I/LA23, M53 NOTE: The molecule of an immunogenic substance contains one or more parts with a characteristic chemical composition, an epitope (ISO 19001).
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antibody specific immunoglobulin formed by B lymphocytes and plasma cells in response to exposure to an immunogenic substance and able to bind to the antigen Project: H56
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antibody a substance formed in the body in response to a foreign protein (an antigen) that interacts only with that substance; however, it may also bind to structurally related substances Project: I/LA30
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antibody a specific immunoglobulin formed by B lymphocytes and plasma cells in response to exposure to an immunogenic substance and able to bind to this immunogenic substance (modified from ISO 19001) Project: NBS06
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antibody the functional component of antiserum or hybridoma supernatant, composed of a population of Y-shaped protein molecules, each member of which is capable of reacting with (binding to) a specific antigenic determinant Project: I/LA28 NOTE: These antibodies are produced by B lymphocytes as a primary immune.
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antibody any of numerous Y-shaped protein molecules produced by B-cells as a primary immune defense, each molecule and its clone having a unique binding site that can combine with the complementary site of an antigen, as on a virus or bacterium, thereby signaling other immune defenses; the functional portion of antiserum, often referred to collectively as a population of molecules, each member of which is capable of reacting with (binding to) a specific antigenic determinant Project: I/LA20 NOTE 1: An antibody molecule is, by definition, monospecific, but it might also be idiospecific, heterospecific, polyspecific, or of unwanted specificity. It cannot be nonspecific, except in the sense of nonimmunochemical binding; NOTE 2: These proteins are immunoglobulins and bind by means of specific binding sites to a specific antigenic determinant.
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antibody specific immunoglobulin formed by B lymphocytes in response to exposure to an immunogenic substance (antigen) and able to bind to this antigen Project: I/LA26 NOTE: The molecule of an immunogenic substance contains one or more parts with a characteristic chemical composition, ie, an epitope.
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antibody binding capacity (ABC) as used in this document, the number of antibody molecules specifically bound to the homologous antigen (receptor) in a cell or microparticle under saturating or near-saturating conditions Project: I/LA24 NOTE 1: Antibody binding capacity is often used as an indirect measure of expression of the homologous antigen, which is usually a cellular receptor or capture antibody on a microsphere. It is in this context that near-saturation binding is required. However, some results given in ABC units (such as titrations) clearly do not imply saturation; NOTE 2: "ABC" has become a general term that does not distinguish between binding capacities for native antibody and fluorochrome-antibody conjugates. It is even used mistakenly to describe the binding capacity for ligands other than antibodies. While terms like "ligand binding capacity," and "conjugate binding capacity" would be more precise, they are rarely used; NOTE 3: Some reports use the variant term "AB/C" to stand for "Antibodies Bound per Cell." This term presumably does not imply a requirement for saturation.
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antibody identification the testing of serum or plasma against a panel of different materials that express red blood cell antigens to identify the antibody or antibodies Project: I/LA33
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antibody screen the testing of serum or plasma with material expressing red blood cell antigens for detection of unexpected antibodies Alternate Term: antibody detection Project: I/LA33
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anticoagulant a natural or pharmacological agent that inhibits clotting of blood or plasma Project: H58, MM17, H59
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anticoagulant an agent that prevents the coagulation of blood or blood products Project: POL1/2, GP34, GP39, H56, POCT04, H21
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anticoagulant a substance that prevents coagulation, ie, it inhibits blood or plasma from clotting Project: H60, H48
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antifatigue mats padded mats that are placed on floors in areas where staff must stand for long periods of time Project: QMS04
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antifungal agent agent that destroys or resists fungus Project: QMS04 NOTE: Antifungal agents are capable of destroying or inhibiting their growth.
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antigen in immunology, any substance that can stimulate the production of antibodies by an organism and combine specifically with them Project: I/LA23, I/LA20, I/LA28, I/LA34 NOTE: This is the name of the measurand in immunohistochemistry assays.
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antigen any substance which, when injected into an animal or human being, elicits an immune response, either cellular, humoral, or both Project: I/LA26, I/LA29
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antigen any substance foreign to the body that evokes an immune response either alone or after forming a complex with a larger molecule (as a protein) and that is capable of binding with a product (as an antibody or T cell) of the immune response Project: m53
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antigen any substance either foreign or native that elicits an immune response through recognition by receptors on the surface of immune cells Project: NBS06
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antigen excess the presence of an amount of antigen, in relationship to antibody concentration, that results in increased solubility of immune complexes, decreased apparent reactivity, and in underestimation of antigen quantity Project: DL01
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antigen retrieval the process of rendering a fixed and paraffin-embedded tissue accessible for binding by antibodies Project: I/LA28 NOTE: Typically, antigen retrieval follows deparaffinization; however, some methods combine the two steps into a single process. At the molecular level, antigen retrieval is the release of covalent cross-links that are most often the result of formalin fixation. Elements of additional deparaffinization and reduction to denatured protein are an element of antigen retrieval. Antigen retrieval is mediated typically by enzymatic methods (trypsin and proteinase K) or heat-based approaches with specific buffers (see heat-induced antigen retrieval and analytical interference). (Some authors prefer the term epitope retrieval.)
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antigenic determinant the minimum molecular structure of the antigenic site that will react with a monoclonal antibody Alternate Term: epitope Project: DI01, I/LA18
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antigenicity the capacity for a substance to react with appropriate antibodies in a suitable in vitro immunological assay, such as flocculation, immunogel diffusion, ELISA
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antigen-presenting cells cells (primarily dendritic cells, monocytes, and B-cells) that are able to bind and internalize large protein antigens, process them, and then present peptide fragments of these antigens to cytotoxic T-cells and T-helper cells in the context of their major histocompatibility complex Class I and Class II surface molecules, respectively Project: I/LA26
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antiglobulin an antibody produced by an animal in reaction to the introduction of globulin from another animal (RHUD1.7CD) Project: I/LA23
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antiglycolytic agent agent that inhibits the utilization of glucose by blood cells Project: GP39
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antihuman globulin an antibody directed against human immunoglobulin and/or complement Alternate Term: AHG phase Project: I/LA33 NOTE: It is used to perform the antihuman globulin test (previously known as Coombs test). The preparation may be either polyspecific (anti-immunoglobulin G plus anticomplement) or monospecific (anti-immunoglobulin G or anticomplement).
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antihuman globulin phase testing step where the use of a secondary antibody, typically directed against human immunoglobulin G or complement component 3 molecules, detects bound immunoglobulin G or complement component 3 on red blood cells (patient, donor, or reagent); the secondary antibody binds to the cell-bound immunoglobulin G or complement component 3 that has attached to the red cell either in vivo or in vitro Alternate Term: AHG phase Project: I/LA33
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antimatrix antibody directed against the solid phase support (ie, microparticles, plastic in enzyme-linked immunosorbent assay [ELISA] plates) that may interfere with the test system by causing high background levels Project: I/LA29
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antimicrobial agent substance of biological, semisynthetic, or synthetic origin that inhibits the growth of or kills bacteria, and is thus of potential use in the treatment of infections (ISO 20776-1) Project: ISO 20776-1 NOTE: Disinfectants, antiseptics, and preservatives are not included in this definition (ISO 20776-1).
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antimicrobial agent agent that destroys or resists microorganisms Project: QMS04 NOTE: Antimicrobials are capable of destroying or inhibiting the growth of microorganisms.
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antimicrobial resistance surveillance the continuous, intensive, targeted, and nonrandom collection of data on the incidence, prevalence, and spread of antimicrobial resistant bacteria and antimicrobial resistance genes Project: VET05
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antimicrobial susceptibility test device (AST device) device including all specified components used to obtain test results that allow susceptible, intermediate, and resistant (SIR) categorization of bacteria with specific antimicrobial agents (ISO 20776-2) Project: ISO 20776-2 NOTE: Specific components include inoculators, disposables and reagents, media, disks, and readers. Nonspecific components, such as swabs, pipettes, and tubes, are not part of the device (ISO 20776-2).
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antimicrobial susceptibility test interpretive category 1) classification based on a bacterium’s in vitro response to an antimicrobial agent relative to that agent's serum concentration (or other relevant fluid concentration) that is attainable using standard of practice dose or the labeled target animal species for that type of infection and infecting organism; 2) susceptible antimicrobial susceptibility test interpretive category - a category that implies that an infection due to the isolate may be appropriately treated with the dosage regimen of an antimicrobial agent recommended for that type of infection and infecting species, unless otherwise indicated; 3) intermediate antimicrobial susceptibility test interpretive category - a category that implies that an infection due to the isolate may be appropriately treated in body sites where the drugs are physiologically concentrated or when a high dosage of drug can be used; also indicates a “buffer zone” that should prevent small, uncontrolled, technical factors from causing major discrepancies in interpretations; 4) resistant antimicrobial susceptibility test interpretive category - resistant isolates are not inhibited by the usually achievable concentrations of the agent with normal dosage schedules and/or fall in the range where specific microbial resistance mechanisms are likely (eg, beta-lactamases), and clinical efficacy has not been reliable in treatment studies Project: VET03
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antimicrobial susceptibility test interpretive category a classification based on an in vitro response of an organism to an antimicrobial agent at levels corresponding to blood or tissue levels attainable with usually prescribed doses of that agent; 1) susceptible – the “susceptible” category implies that isolates are inhibited by the usually achievable concentrations of antimicrobial agent when the dosage recommended to treat the site of infection is used; 2) susceptible-dose dependent (SDD) – the “susceptible-dose dependent” category implies that susceptibility of an isolate is dependent on the dosing regimen that is used in the patient. In order to achieve levels that are likely to be clinically effective against isolates for which the susceptibility testing results (either minimal inhibitory concentrations [MICs] or disk diffusion) are in the SDD category, it is necessary to use a dosing regimen (ie, higher doses, more frequent doses, or both) that results in higher drug exposure than the dose that was used to establish the susceptible breakpoint. Consideration should be given to the maximum approved dosage regimen, because higher exposure gives the highest probability of adequate coverage of an SDD isolate. The dosing regimens used to set the SDD interpretive criterion are provided in Appendix E of CLSI document M100. The drug label should be consulted for recommended doses and adjustment for organ function; 3) intermediate – the “intermediate” category includes isolates with antimicrobial agent MICs that approach usually attainable blood and tissue levels, and for which response rates may be lower than for susceptible isolates. The intermediate category implies clinical efficacy in body sites where the drugs are physiologically concentrated (eg, quinolones and β-lactams in urine) or when a higher than normal dosage of a drug can be used (eg, β-lactams). This category also includes a buffer zone, which should prevent small, uncontrolled, technical factors from causing major discrepancies in interpretations, especially for drugs with narrow pharmacotoxicity margins; 4) resistant – the “resistant” category implies that isolates are not inhibited by the usually achievable concentrations of the agent with normal dosage schedules, and/or that demonstrate MICs or zone diameters that fall in the range where specific microbial resistance mechanisms (eg, β-lactamases) are likely, and clinical efficacy of the agent against the isolate has not been reliably shown in treatment studies; 5) nonsusceptible – a category used for isolates for which only a susceptible interpretive criterion has been designated because of the absence or rare occurrence of resistant strains. Isolates for which the antimicrobial agent MICs are above or zone diameters below the value indicated for the susceptible breakpoint should be reported as nonsusceptible; NOTE 1: An isolate that is interpreted as nonsusceptible does not necessarily mean that the isolate has a resistance mechanism. It is possible that isolates with MICs above the susceptible breakpoint that lack resistance mechanisms may be encountered within the wild-type distribution subsequent to the time the susceptible-only breakpoint is set; NOTE 2: For strains yielding results in the “nonsusceptible” category, organism identification and antimicrobial susceptibility test results should be confirmed NOTE: The SDD interpretation is a new category for antibacterial susceptibility testing, although it has been previously applied for interpretation of antifungal susceptibility test results (see CLSI document M27-S4). The concept of SDD has been included within the intermediate category definition for antibacterials. However, this is often overlooked or not understood by clinicians and microbiologists when an intermediate result is reported. The SDD category may be assigned when doses well above those used to calculate the susceptible breakpoint are approved and used clinically, and where sufficient data to justify the designation exist and have been reviewed. When the intermediate category is used, its definition remains unchanged.
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antimicrobial susceptibility test interpretive category a classification based on an in vitro response of an organism to an antimicrobial agent at levels corresponding to blood or tissue levels attainable with usually prescribed doses of that agent. 1) susceptible (S) – a category that implies that isolates are inhibited by the usually achievable concentrations of antimicrobial agent when the dosage recommended to treat the site of infection is used. 2) intermediate (I) – a category that includes isolates with antimicrobial agent minimal inhibitory concentrations (MICs) that approach usually attainable blood and tissue levels and for which response rates may be lower than for susceptible isolates; NOTE: The intermediate category implies clinical efficacy in body sites where the drugs are physiologically concentrated (eg, quinolones and lactams in urine) or when a higher than normal dosage of a drug can be used (eg, lactams). This category also includes a buffer zone, which should prevent small, uncontrolled, technical factors from causing major discrepancies in interpretations, especially for drugs with narrow pharmacotoxicity margins. 3) resistant (R) – a category that implies that isolates are not inhibited by the usually achievable concentrations of the agent with normal dosage schedules and/or that demonstrate zone diameters that fall in the range in which specific microbial resistance mechanisms (eg, -lactamases) are likely, and clinical efficacy of the agent against the isolate has not been reliably shown in treatment studies.
4) nonsusceptible (NS) – a category used for isolates for which only a susceptible interpretive criterion has been designated because of the absence or rare occurrence of resistant strains. Isolates for which the antimicrobial agent MICs are above or zone diameters below the value indicated for the susceptible breakpoint should be reported as nonsusceptible; NOTE 1: An isolate that is interpreted as nonsusceptible does not necessarily mean that the isolate has a resistance mechanism. It is possible that isolates with MICs above the susceptible breakpoint that lack resistance mechanisms may be encountered within the wild-type distribution subsequent to the time the susceptible-only breakpoint is set; NOTE 2: For strains yielding results in the “nonsusceptible” category, organism identification and antimicrobial susceptibility test results should be confirmed.
Project: M45
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antimicrobial susceptibility test interpretive category classification of projected clinical outcome of treatment based on the causative microorganism’s in vitro response to an antimicrobial agent relative to the exposure to that agent, which is attainable using the labeled dose regimen for the target animal species for that type of infection and infecting organism Project: VET05
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antimicrobial susceptibility test interpretive category a classification based on an in vitro response of an organism to an antimicrobial agent at levels corresponding to blood or tissue levels attainable with usually prescribed doses of that agent. 1) susceptible - a category that implies that isolates are inhibited by the usually achievable concentrations of antimicrobial agent when the dosage recommended to treat the site of infection is used; 2) intermediate - a category that includes isolates with antimicrobial agent minimal inhibitory concentrations that approach usually attainable blood and tissue levels and for which response rates may be lower than for susceptible isolates. The intermediate category implies clinical efficacy in body sites where the drugs are physiologically concentrated (eg, quinolones and β-lactams in urine) or when a higher than normal dosage of a drug can be used (eg, β-lactams). This category also includes a buffer zone, which should prevent small, uncontrolled, technical factors from causing major discrepancies in interpretations, especially for drugs with narrow pharmacotoxicity margins; 3) resistant - a category that implies that isolates are not inhibited by the usually achievable concentrations of the agent with normal dosage schedules and/or that demonstrate minimal inhibitory concentrations that fall in the range in which specific microbial resistance mechanisms (eg, β-lactamases) are likely, and clinical efficacy of the agent against the isolate has not been reliably shown in treatment studies Project: M43
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antimicrobial susceptibility testing procedures used to determine the susceptibility of bacteria to a specific antimicrobial agent(s) Project: M07, M02 Source: Microbiology Glossary NOTE: There are two major testing types, disk diffusion and dilution (broth and agar).
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antinuclear antibodies as used in this guideline, immunoglobulins detected by immunochemical staining of cells that bind specifically to cell nuclei or certain antigens in the cytoplasm, and immunoglobulins that bind specifically to certain purified nuclear or cytoplasmic antigens detected by binding reactions in gel precipitation assays, ELISA, and other assay methods such as protein microarrays Project: I/LA02
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antisense strand strand of DNA complementary to the sense strand
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antisepsis method for avoiding infection in a wound or during a clinical procedure by the use of a chemical agent such as an antiseptic (ISO 15190) Project: ISO 15190
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antiseptic chemical germicide formulated to be used on skin or tissue (ISO 15190) Project: ISO 15190, M29, I17 NOTE 1: Antiseptics should not be used as disinfectants; NOTE 2: The US Food and Drug Administration has regulatory authority over antiseptic compounds.
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antiseptic a substance that inhibits the growth and development of microorganisms without necessarily killing them Project: M47
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antiserum a serum produced in animals or human beings that contains antibodies to one or more antigens of interest Project: ILA18
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antiserum a serum produced in various species of animals or human beings that contains antibodies to one or more antigens of interest Project: I/LA28
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antithrombin (formerly antithrombin III) a plasma protein that, when activated by heparin or heparin-like molecules containing a specific pentasaccharide sequence such as glucosaminoglycans on endothelial cells, is a potent, irreversible inhibitor of activated, procoagulant serine proteases such as thrombin and factor Xa Project: POCT14
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antiviral resistance a decrease in susceptibility to an antiviral drug that can be clearly established by in vitro testing and can be confirmed by genetic analysis of the virus and biochemical study of the altered enzymes Project: M33 NOTE 1: In vitro drug resistance must be distinguished from treatment failure in which the viral infection fails to respond to therapy. This failure may or may not be due to the presence of a drug-resistant virus, but may be related to the pharmacokinetics of the drug in an individual patient and the patient’s immunologic status; NOTE 2: For HSV, in vitro resistance to antiviral agents such as acyclovir and foscarnet has been correlated with clinical resistance.
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antivitamin K plasma plasma from an individual on antivitamin K therapy Alternate Term: AVK plasma Project: H54
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apheresis the withdrawal of whole blood from the body, separation of one or more components, and return of remaining blood to the donor by transfusion Project: QMS04
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apolipoprotein the lipid-free protein moiety of a lipoprotein NOTE: Several different apolipoproteins have been identified that differ in structure, function, and genetic control.
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apoptosis the process of programmed cell death resulting from specific cell signaling events Project: I/LA26
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application the purpose and context in which a sequencing technology is applied, including clinical indication, nucleic acid template structure, specified technical characteristics, and specimen types Project: MM09
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application-specific settings user-specified instrument settings based on mean fluorescence intensity, median fluorescence intensity, or geometric-mean fluorescence intensity target values using fluorescence reference particles to set up an instrument’s fluorescence detector voltages for a defined assay or application Alternate Term: assay-specific settings Project: H62
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appraisal costs costs associated with measuring, evaluating, or auditing products or services to ensure conformance to quality standards and performance requirements Project: QMS20
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arbitrator a qualified examiner, frequently with additional expertise and experience, who will resolve disagreements between the results of two qualified morphologist examiners Project: H20
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arcing electrical conduction through a gas in an applied electric field Project: GP28
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area under the curve (area under the receiver operating characteristic curve) as applied to receiver operating characteristic curves, the area subtended by the receiver operating characteristic curve and bounded by the x-axis (false-positive fraction) and the y-axis (true-positive fraction) Alternate Term: AUC Project: I/LA21 NOTE 1: By convention, the total area in receiver operating characteristic space is exactly 1 unit. A completely noninformative receiver operating characteristic curve will divide the total receiver operating characteristic space into two equal triangular areas of 0.5 units each. The area under the curve of an informative receiver operating characteristic must therefore be > 0.5 area units. A test with perfect discrimination would have an area under the curve of 1.0 area units; NOTE 2: The area under the curve is mathematically related or equivalent to certain statistical parameters, particularly the Mann-Whitney U; NOTE 3: Various mathematical approaches to calculating the area under the curve are available. The simplest is the trapezoidal approximation. More formal parametric and nonparametric approaches can be used; NOTE 4: The area under the curve is a good measure of the overall accuracy of a test but does not distinguish between sensitivity and specificity.
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area under the curve the computed area (definite integral) under the concentration-time curve. Practically, it is a pharmacokinetic measure of total exposure of drug over a defined time interval or time-averaged concentration of drug in the body Project: M23
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Arrhenius equation a mathematical function that describes the approximate relationship between the rate constant of a chemical reaction and the reaction temperature and energy of activation Project: EP25
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arterial oxygen tension-inspired oxygen fraction ratio [PO2(aB)/FIO2//PaO2/FIO2] - the ratio of the partial pressure of oxygen in arterial blood to the fraction of inspired oxygen Project: NRSCL8
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arterial puncture the procedures for collecting a blood sample from an artery Project: POCT04 NOTE: This blood is called “arterial blood.”
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arterial-alveolar oxygen tension ratio [PO2(aB)/PO2 (A)//PaO2/PAO2//a/A ratio] ratio of the partial pressure of oxygen in arterial blood to the partial pressure of oxygen in alveolar gas Project: C12, C25
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arterialization increasing blood flow through capillaries to more closely resemble arterial blood Project: GP42
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arthrocentesis aspiration of a joint Project: H56
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arthrocentesis fluid joint fluid obtained from aspiration of a joint Project: H56
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arthroconidium (pl. arthroconidia) spore formed by disarticulation from a hypha at the point of a septation; often rectangular or barrel-shaped Project: M54
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artifact an inaccurate observation, effect, or result, especially one resulting from the technology used in scientific investigation or from experimental error Project: MM09
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artificial analyte component created or manufactured for use in spiking surrogate samples, with the intention of emulating the characteristic of the human specimen that will be measured or detected Project: EP39 EXAMPLES: Synthesized chemical compounds, plasmid or cell-line DNA, transcript RNA, recombinant protein, cell culture used to reproduce an artificially created organism.
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artificial matrix milieu that is created or manufactured with the intention of emulating the specimen biological matrix Project: EP39 EXAMPLES: Collection media, elution media, isotonic solutions, human or bovine serum albumin dissolved in buffer.
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ascitic fluid serous fluid from the peritoneal cavity Project: I/LA18 NOTE: Monoclonal antibodies are commonly raised in vivo by implantation of hybridomas in the peritoneal cavity of mice, followed by purification of the antibodies from the resulting ascitic fluid.
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aseptic environmental conditions which minimize microbial contamination Project: C37
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assay 1) a quantitative determination or measurement of the amount, activity, or potency of a constituent or characteristic; 2) competitive binding assay - assay based on the competition of labeled and unlabeled analytes for a receptor (Cf. DI1); 3) assay - to analyze or measure a sample of a specimen to determine the amount, activity, or potency of a specific analyte or substance; 4) qualitative assay - reports only the presence or absence of the analyte, without quantitation; 5) quantitative assay - generates a spectrum of signal responses that correlate with the concentration of the analyte of interest; 6) semiquantitative assay - essentially a qualitative assay with an additional option for the response range (degree of positivity, dilution to which positive results are obtained, or comparison to a color chart) Project: DI01, I/LA18, I/LA23, I/LA33, MM22, MM24 NOTE 1: A positive test result implies only that the assay signal exceeds the analytical threshold (detection limit) or a cutoff point set to give an arbitrary combination of sensitivity and specificity; NOTE 2: In simplistic and idealistic terms, detection of the analyte should correlate with the presence (and nondetection with the absence) of the infectious agent or of related antibodies, resulting from either natural exposure or immunization; NOTE 3: If the analyte preparations with known concentrations are available for calibration, the actual concentration of the analyte can be determined; NOTE 4: For the purpose of this document, assay is also known as the measurement procedure (see the definition in this section); NOTE 5: A qualitative assay reports only the presence or absence of the analyte, without quantification; NOTE 6: For the purpose of MM22 and MM24, assay is also known as the measurement procedure.
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assay See measurement procedure Project: EP05
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assay as used in CLSI document I/LA28, the technical element of the immunohistochemical assay, exclusive of interpretation or reporting (see test) Project: I/LA28
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assay intended use population a group of subjects intended to be tested by the assay in question (eg, with genotypes and phenotypes representative of the population)
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assay range the upper and lower limits of the amount, activity, or potency of a specific analyte between which measurement is possible Project: NRSCL8
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assay sensitivity See sensitivity Project: ILA29
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assay value the amount, activity, or potency of an analyte as determined by analysis Project: NRSCL8
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assayed quality control material control materials with assigned analyte values provided by the manufacturer Project: EP23
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assembly the tube and the closure Project: GP39
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assembly the process of constructing sequences containing overlapping regions Project: MM09, MM18 NOTE: This process is generally performed to generate a consensus sequence if multiple sequencing reactions are performed on a single amplicon.
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assessment systematic process to collect and analyze data to determine the current, historical, or projected status of an organization, person, process, or project Project: QMS06, QMS01 Source: Quality Glossary NOTE: Siebels DL, "The Quality Improvement Glossary"
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assessment (of target condition [TC]) the best available method for assessing the TC Project: EP12 NOTE 1: Referred to as clinical reference standard in Standards for Reporting of Diagnostic Accuracy Studies (STARD); NOTE 2: The classification by this method is seen as a true binary determination; NOTE 3: May be a method developed through clinical consensus that determines whether a specimen is from an individual with or without the TC; NOTE 4: For analyte-detection examinations, the determination may be made, for example, by a composite reference method that includes multiple tests and/or methods and an algorithm for combining their results into a binary categorization.
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assessor representative of the assessment organization who determines whether the laboratory meets the assessment organization’s requirements Project: QMS17 Source: Quality Glossary NOTE: An assessor can also be referred to as an inspector, auditor, surveyor, or investigator.
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asset any resource both available and useful during disaster response Project: GP36
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asset single object in the laboratory containing a specimen or derivative of a specimen from a single patient Project: AUTO14 NOTE: A single asset typically has one but can have multiple bar codes, which are either etched or applied using labels. Each bar code with its associated human-readable information should represent the unique specimen on which it is applied or etched
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asset key single unique identifier for a single object in the laboratory Project: AUTO14 NOTE: This single object can be a single specimen, block, slide, tube, aliquot, document, or other object representing something about or from a single patient
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assigned value value attributed to a particular property of a proficiency test item (ISO 13528) Project: QMS24
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assigned value value attributed to a particular quantity and accepted, sometimes by convention, as having an uncertainty appropriate for a given purpose Project: EP10
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assisted monitoring of blood glucose an instance in which the testing procedure is performed by a health care provider for an individual or individuals Project: POCT04
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ASTM International the official name of the organization formerly known as the American Society for Testing and Materials Project: AUTO01, AUTO07, AUTO02, AUTO03 NOTE: ASTM International has developed various high- and low-level communications protocols.
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ataxia a neurological sign and symptom consisting of gross lack of coordination of muscle movements. Ataxia is a nonspecific clinical manifestation implying dysfunction of parts of the nervous system that coordinate movement, such as the cerebellum NOTE: Several possible causes exist for these patterns of neurological dysfunction.
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atomic mass unit 1/12th of the atomic mass of 12C (carbon-12) Project: NBS04, NBS09 NOTE: Although there is currently no International System of Units term or symbol for “daltons,” both the terms and symbols “atomic mass unit” and “amu” and “dalton” and “Da” are equally valid in mass spectrometry.
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atopy the inherited tendency to develop immediate-type hypersensitivity to common and generally harmless substances Project: I/LA34
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atopy the inherited tendency to develop immediate-type hypersensitivity to common and generally harmless substances and/or develop atopic diseases (eg, allergic rhinoconjuncitivitis, allergic asthma, atopic eczema, and immunoglobulin E−mediated food allergies) Project: I/LA20 NOTE: A predisposition for atopy (atopic status) can be identified by demonstrating sensitization (immunoglobulin E antibody positivity).
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attestation the responsibility of the individual testing or examining the samples and the laboratory director to testify to the routine integration of the samples into the patient workload using the laboratory’s routine methods (42 CFR 1236) Project: MM14
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atypical a term used by pathologists to describe cells or tissues having some or all of the morphologic characteristics associated with malignancy Project: MM02
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audit systematic, independent, and documented process to obtain and evaluate evidence objectively to determine the extent to which specified criteria are fulfilled (modified from ISO 9000, ISO 19011) Project: QMS06, QMS15, QMS16, QMS21, QMS01, QMS17 Source: Quality Glossary
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audit conclusion outcome of an audit, after consideration of the audit objectives and all audit findings (ISO 9000)
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audit criteria set of policies, procedures, or requirements used as a reference (modified from ISO 9000, ISO 19011) Project: QMS15
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audit evidence records, statements of fact, or other information which are relevant to the audit criteria and verifiable (ISO 9000)
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audit plan description of the activities and arrangements for an audit (ISO 9000, ISO 19011) Project: QMS15
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audit program set of activities to identify internal audits and auditors, train auditors, and schedule and conduct internal audits Project: QMS15
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audit sample testing testing of stored aliquots from a biological sample repeatedly over time in a specific assay system Project: QMS24
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audit scope extent and boundaries of an audit (ISO 9000, ISO 19011) Project: QMS15
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audit team one or more auditors conducting an audit, supported if needed by technical experts (modified from ISO 9000, ISO 19011) Project: QMS15
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audit trail an electronic log of transactions, detailing all events that have occurred in the laboratory automation system, including date and time of these events, which operator was responsible or directs processes, and any additional details Project: AUTO01, AUTO02, AUTO03
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audit trail 1) data in the form of a logical path linking a sequence of events, used to trace the transactions that have affected the contents of a record; 2) a chronological record of system activities that is sufficient to enable the reconstruction, reviews, and examination of the sequence of environments and activities surrounding or leading to each event in the path of a transaction from its inception to output of final results (ISO/IEC International Standard 812) Project: AUTO08
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auditee organization (or function) being audited (modified from ISO 9000) Project: QMS15
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auditor person with the competence to conduct an audit (modified from ISO 9000, ISO 19011) Project: QMS15
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authentication the process of verifying the identity of a user, process, or device, often as a prerequisite to allowing access to resources in an information system Project: AUTO11 NOTE: This process is usually achieved by supplying the user identification and a unique password (what the user knows), security token (what the user has), or biometrics (who the user is).
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authenticator role played by a laboratory clinical expert when performing clinical validation of a set of results issued in a Clinical Document Architecture Release 2 laboratory report, by which this person authenticates and endorses the laboratory report or a subset of it Project: AUTO16
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authorization recognition of a person who has satisfied the qualification requirements to perform point-of-care blood glucose testing within an institution Project: POCT12, POCT13
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authorization the process of granting rights or access to systems, applications, or networks Project: AUTO11 NOTE: Authorization determines who is trusted for a given purpose.
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authorized representative any natural or legal person established within a country or jurisdiction who has received a mandate from the manufacturer to act on his behalf for specified tasks with regard to the latter's obligations under that country's or jurisdiction's legislation (ISO 18113-1) Project: ISO 18112-1, ISO 18113-1, ISO 18113-2, ISO 18113-3 NOTE 1: In the European Union, Directive 98/79/EC [38] requires the manufacturer to designate an “EC authorized representative”, established in the European Community if the manufacturer is not located in the European Community (ISO 18113-1); NOTE 2: Adapted from Directive 98/79/EC of the European Parliament and the Council of 27 October 1998 on in vitro diagnostic medical devices, Official Journal of the European Union L331, December 7, 1998 (ISO 18113-1).
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autoantibody an antibody that an organism produces against any of its own tissues, cells, or cell components (RHUD1.7CD) Project: DL01
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autochthonous (autologous) derived from the subject itself Project: DI01
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autochthonous describes a microorganism that is indigenous to a specific environment Project: M56
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autocontrol where the serum or plasma and red blood cells from the same individual are combined and undergo the same test conditions as the serum and reagent panel cells Project: I/LA33
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autofluorescence the intrinsic fluorescence of unstained cells, generally caused by pyrimidines and flavin nucleotides Project: H43, H42, H52 NOTE 1: The level of autofluorescence is a function of the excitation wavelength and varies with the cell type analyzed and/or the state of cellular activation. Cultured cell lines, neutrophils, and macrophages usually demonstrate higher levels of autofluorescence with 488 nm excitation, and proportional lower autofluorescence with excitation at longer wavelengths (eg, 635 nm). Autofluorescence can be decreased by specific sample preparation procedures (eg, incubation with crystal violet); NOTE 2: The level of autofluorescence is a function of the excitation wavelength and varies with the cell type analyzed and/or the state of cellular activation. Cultured cell lines, neutrophils, and macrophages usually demonstrate higher levels of autofluorescence with 488 nm excitation, and proportional lower autofluorescence with excitation at longer wavelengths. Autofluorescence of red blood cells is significantly lower than that of white blood cells, and instrument settings may need to be adjusted accordingly.
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autofluorescence background fluorescence arising from intrinsic sources in unstained measurands (particularly cells) under conditions used to detect desired fluorochromes Project: I/LA24
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autograft a tissue grafted into a new position in and/or on the body of the person from whom it was removed Project: DI01
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autoimmunization the process of becoming immune against constituents of one’s own cells, tissue, or components thereof Project: DI01
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automated 1) a characterization applied when all analytical processes, including sample and reagent uptake, sample/reagent interaction, chemical/biological analysis, result calculation, and result readout are mechanized; 2) an inclusive term to denote the instrument, reagents, and methods of the device under study Project: AUTO01, AUTO02, H20, AUTO03 NOTE: These are usually controlled by a set of stored, modifiable instructions (US CFR 493 February 28, 1992).
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automated blood culture system a blood culture system that uses mechanical systems to incubate, agitate, and/or monitor blood culture bottles for microbial growth Project: M47
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automated instrument a laboratory instrument that may or may not be connected to a laboratory information system, hospital information system, and/or laboratory automation system, which performs measurements on a patient's sample Project: AUTO01, AUTO02 NOTE: These instruments may have specific hardware and/or software modifications that allow interface to a laboratory automation system.
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automated MIS MIS in which all, or most, steps (eg, inoculation, incubation, result interpretation) are performed by an instrument Project: M50
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automated skin puncture device a single-use device that punctures or cuts the skin with a lancet or blade that automatically retracts into a protective housing; used for collecting a capillary blood specimen
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automated system a system that may be fully automated or semiautomated Project: I/LA33
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automated system administration software module that verifies accessibility and all aspects of security are controlled; pertains to management of the information infrastructure within the automated system Project: I/LA33 NOTE: Management includes functions such as installation of software updates; configuration of test definitions, queries, reports, or new workstations; creation of user accounts (ie, assignment of user passwords and user access levels); inactivation of users; and completion of software preventive maintenance requirements such as system backups and monitoring and allocation of mass storage space.
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automation system a variety of possible systems that can include some of the following types: automated instruments, laboratory information systems, laboratory automation systems, hospital information systems, and front-end processing devices Project: AUTO01, AUTO02
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automation system any of a variety of possible hardware systems that can include one or more of the following types: automated analyzers, modular or task-targeted automated systems (eg, accessioning systems, aliquotters, storage systems), and total laboratory automation systems (eg, track systems that can connect and operate input-output units, automated analyzers, and other task-targeted devices such as aliquotters, centrifuges, and storage units). These automation systems might be operated by or have interfaces to hospital information systems, laboratory information systems, and laboratory automation systems. Project: AUTO12, AUTO14 NOTE: See laboratory automation system and laboratory information system
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autonomy the right to choose one’s own actions or course of life so long as doing so does not interfere unduly with the lives and actions of others Project: GP45 NOTE: Autonomy is the basis of the ethical value of respect for persons and respect for the subjects in research studies, and forms the basis of requirements for informed consent, protection of vulnerable subjects, and maintaining confidentiality of research data.
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autoradiography the process by which a radioisotope (usually 32P or 35S) or chemiluminescent tag is located within a gel or on a sheet of nitrocellulose paper by placing photographic or x-ray film in contact (inside a dark “holder”) with the gel or paper and waiting for several hours or several days for “exposure” to occur Project: MM10, MM24 NOTE: When developed, the film will display an image of all the tagged molecules in the gel or on the nitrocellulose and thus pinpoint their locations and relative positions within the gel or on the nitrocellulose.
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autosampler mechanical device used to reliably and reproducibly introduce accurately known volumes of specimen extracts into a flow stream for analysis Project: NBS04, NBS09 NOTE: In NBS04 and NBS09, analysis is by tandem mass spectrometry.
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autoverification (automated result verification) the automated actions performed by a computer system related to the release of test results to the medical record using criteria and logic established, documented, and tested by the medical staff of the laboratory Project: AUTO10, AUTO15 NOTE: The criteria can be simple or complex and involve many different parameters. The system offers the highest levels of consistency and the ability to handle complex algorithms in a very efficient way.
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autoverification the automated actions performed by a computer system related to the release of test results to the medical record using criteria and logic established, documented, and tested by the laboratory staff Project: EP33 NOTE: The criteria can be simple or complex and involve many different variables. The system offers the highest levels of consistency and the ability to handle complex algorithms in a very efficient way.
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autoverification parameter (table) a listing of the causes (eg, results, flags, alerts) and effects (eg, rerun, reflex, addition of text) of specific details for a given algorithm Project: AUTO15
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autoverification rate usually expressed as a percentage, the number of results that are sent directly to the patient record without human intervention to review the data before being sent out. This should be measured by analyte and not by patient Project: AUTO15
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average affinity constant the average affinity constant of a population of antibody molecules Project: NRSCL8 NOTE: The average or mean affinity constants are usually described for polyclonal antisera because of their heterogeneity.
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avidity net affinity of all binding sites of antibodies Project: I/LA30
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avidity the net affinity of all binding sites of all antibodies in the antiserum, under specified physicochemical reaction conditions Project: NRSCL8, I/LA23, ILA29 NOTE: It is a function of the affinities of the antibody-combining sites on all antibodies present in an antiserum and all of the antigenic determinants of available macromolecules.
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avidity a measure of strength of bi- or multivalent antigen/antibody interaction Project: I/LA28
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AVK plasma See antivitamin K plasma Project: H54
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azeotrope a blend of two or more components with equilibrium vapor phase and liquid phase compositions that are the same at a given temperature and pressure Project: GP40
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azoospermia the medical condition of a male not having any measurable level of sperm in his semen. It is associated with very low levels of fertility
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backdraft exhaust vents located at the back of the countertop, designed to take chemical fumes that are heavier than air out of a space Project: QMS04
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background any signal that is measured but does not originate from the parameter of interest Project: H62 NOTE: In flow cytometry, instrument background refers to the contribution of the signal produced by background light.
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backsplash small strip placed on top of a countertop, at the back, to protect the wall Project: QMS04
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backup a copy of computer data Project: QMS22 NOTE: A backup may be in the form of a file or the contents of a computer hard drive.
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bacteremia the presence of bacteria in the bloodstream Project: M47
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bactericide a chemical or physical agent that kills bacteria Project: GP40
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badge familiar, externally visible identification device Project: GP36 NOTE: Badges may also be generated by emergency agencies during an incident, and may bear expiration dates and specific access restrictions.
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balanced describes an experimental design or dataset wherein all cells (“treatment combinations”) have the same number of observations. A design or dataset is unbalanced if this condition fails to hold Project: EP05 NOTE: In concrete terms, for precision studies of the kind discussed in Chapters 3 and 4 of EP05, the experimental design is balanced if, for any given sample, it specifies the same number of replicates for each run; the same number of runs for each day; and, for a multisite study, the same number of days for each site. Otherwise, the design is unbalanced. (Note that all designs recommended in EP05 are balanced.) The corresponding dataset is balanced if it has the same number of results for each run, day, and site—ie, if the design is balanced and no results are missing or omitted from the analysis. Otherwise, the dataset is unbalanced.
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balanced scorecard a management tool that provides feedback on both internal business processes and external outcomes to continuously improve strategic performance and results Project: QMS12 Source: Quality Glossary
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bar code 1) an array of parallel rectangular bars and spaces that creates a symbology representing a number or alphanumeric identifier; 2) an array of rectangular lines and spaces that is arranged in a predetermined pattern following unambiguous rules and representing data that are referred to as characters (ASTM F1156); 3) an identification code consisting of a pattern of vertical bars whose width and spacing identify the item marked Project: AUTO01, AUTO07, AUTO02, AUTO03, I/LA33, AUTO12 NOTE: The code is meant to be read by an optical input device, such as a bar code scanner. Applications include retail product pricing labels, identification of library documents, and railroad boxcar identification (IEEE 610.2).
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bar code content construction software the software that constructs the CLSI AUTO14-compliant content string from specimen ID information in the health care application or database according to the specifications set forth in Chapter 4. Project: AUTO14
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bar code content utilization software software within a health care application that parses the content received from a decoded bar code, verifies the compliance of its format, and subsequently determines if the data within the bar code content exactly matches the correct unique specimen, aliquot or asset that has already been entered into the health care application Project: AUTO14
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bar code density the density of a bar code symbol, whether linear or two-dimensional, refers to the space efficiency with which that particular symbol encodes data Project: AUTO14 NOTE 1: High-density linear symbols use a smaller width of the narrow bar/space (element) than low-density linear symbols. Similarly, high-density two-dimensional symbols use smaller cells (dark/light) than low-density two-dimensional symbols. Regardless of symbol density, it is important to test the symbol with every bar code reader (handheld or fixed-mounted) that will be required to decode that symbol to establish compatibility of symbol density to bar code reader resolution; NOTE 2: Density is customarily expressed by the nominal width dimension of the narrow element in linear bar code symbols and the cell in two-dimensional bar code symbols. The unit of measure varies regionally but is typically either mil (0.001 inch) or millimeter. This dimension is typically referred to as the “X-Dimension.”
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bar code module the smallest individual element in a bar code Project: AUTO14 NOTE 1: In a linear bar code, a module is the narrowest element (bar or space) in a bar code; NOTE 2: In a two-dimensional bar code, a module is the smallest rectangular or square element (cell) in the bar code. Both linear and two-dimensional bar codes are constructed of multiple modules of the same or different widths (see X-dimension)
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bar code reader any device used to "read" (also decode) a bar code symbol Project: AUTO14 NOTE: Most devices used to decode two-dimensional symbols use camera-based technology
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bar code system a group of components, such as reading devices, printers, labels or applicators, and software, designed to use bar codes to facilitate the automatic collection of data, tracking, and the subsequent generation of useful output (reports, summaries, etc.) Project: AUTO14
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bar code, linear (one-dimensional) 1) an array of parallel rectangular bars and spaces that creates a symbology representing a number or alphanumeric identifier; 2) an array of rectangular lines and spaces that is arranged in a predetermined pattern following unambiguous rules and representing data that are referred to as characters; 3) an ID code consisting of a pattern of vertical bars whose width and spacing identifies the item marked Project: AUTO14 NOTE: The code is meant to be read by an optical input device, such as a bar code reader. Applications include retail product pricing labels, ID of library documents, and railroad boxcar ID.
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bar code, two-dimensional a graphical image that stores information both horizontally and vertically Project: AUTO14 NOTE: As a result of that construction, two-dimensional codes can store significantly more data than is possible with the capacity of a linear bar code
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bar length the length of the bars in the bar code Project: AUTO01, AUTO07, AUTO02, AUTO12
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base call ability to distinguish presence of an adenine (A), a thymine (T), a cytosine (C), or a guanine (G) at a given position within a sequence or compilation of overlapping sequences Project: MM10, MM18, MM09, MM24 NOTE: Positions may be ambiguous and represented by an S (G or C), W (A or T), K (G or T), Y (C or T), M (A or C), R (A or G), B (C, G, or T), D (A, G, or T), H (A, C, or T), V (A, C, or G), or N (any base).
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base excess the substance concentration of base, determined by titration with strong acid under specified conditions Project: NRSCL8
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base excess of blood the substance concentration of base determined by titration of blood with a strong acid or base to a pH of 7.40 with a partial pressure of carbon dioxide of 40 mmHg (5.3 kPa) at 37°C Alternate Term: in vitro base excess, cBE(B), (BEvt) Project: C46 NOTE: This can be determined by titration of blood with a strong acid or base to a plasma pH of 7.40 with partial pressure of carbon dioxide at 40 mmHg and at 37°C, but routinely is determined on the basis of a standardized equation found in CLSI/NCCLS document C12.
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base excess of extracellular fluid the {substance} concentration of base determined by titrating a model of extracellular fluid to a pH of 7.40 with a partial pressure of carbon dioxide of 40 mmHg (5.3 kPa) at 37°C Alternate Term: in vivo base excess, cBE(ecf), (Bevv) Project: C46 NOTE 1: The model may be obtained by diluting one volume of blood with two volumes of its own plasma (IFCC/EPpH95); NOTE 2: This quantity cannot be determined directly, as can cBE(B), but it is determined in practice based on a standardized equation found in CLSI/NCCLS document C12.
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base quantity quantity in a conventionally chosen subset of a given system of quantities, where no subset quantity can be expressed in terms of the others (JCGM 200:2012) Project: ISO IEC Guide 99 NOTE 1: The subset mentioned in the definition is termed the "set of base quantities"; EXAMPLE: The set of base quantities in the International System of Quantities (ISQ) is given in 1.6 (JCGM 200:2012); NOTE 2: Base quantities are referred to as being mutually independent since a base quantity cannot be expressed as a product of powers of the other base quantities (JCGM 200:2012); NOTE 3: ‘Number of entities’ can be regarded as a base quantity in any system of quantities (JCGM 200:2012).
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base unit measurement unit that is adopted by convention for a base quantity (JCGM 200:2012) Project: ISO IEC Guide 99 NOTE 1: In each coherent system of units, there is only one base unit for each base quantity; EXAMPLE: In the SI, the metre is the base unit of length. In the CGS systems, the centimetre is the base unit of length (JCGM 200:2012); NOTE 2: A base unit may also serve for a derived quantity of the same quantity dimension; EXAMPLE: Rainfall, when defined as areic volume (volume per area), has the metre as a coherent derived unit in the SI (JCGM 200:2012); NOTE 3: For number of entities, the number one, symbol 1, can be regarded as a base unit in any system of units (JCGM 200:2012).
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basic local alignment search tool computer algorithm designed to find regions of local similarity between nucleic acid sequences. The program compares nucleotide sequences with sequence databases and calculates the statistical significance of matches Project: MM06
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basic local alignment search tool pairwise alignment algorithm that aligns two sequences Project: MM18 NOTE 1: Basic local alignment search tool is an open source tool for sequence alignment; therefore, it can be used by many database providers; NOTE 2: Basic local alignment search tool uses a scoring matrix to generate the best possible local alignment between two sequences.
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basic safety protection against direct physical hazards when medical devices are properly used under normal, or reasonably foreseeable, conditions relating, for example, to mechanical strength, biocompatibility, and sterility (ISO Guide 63-2.1) Project: ISO Guide 63-2.1
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basket trial a clinical trial that tests how well a new drug or other substance works in patients who have different types of cancer but have the same variant or biomarker Alternate Term: bucket trial Project: MM26 NOTE 1: In basket trials, patients receive the same treatment targeting the specific variant or biomarker found in their cancer type; NOTE 2: Basket trials can enable new drugs to be tested and approved more quickly than traditional clinical trials; NOTE 3: Basket trials can also be useful for studying rare types of cancers and cancers with rare genetic changes; NOTE 4: Also known as a bucket trial.
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batch defined amount of material that is uniform in its properties and has been produced in one process or series of processes (ISO 18113-1) Alternate Term: lot Project: ISO CD 18112-1, ISO 18113-1, ISO 18113-2, ISO 18113-4, I/LA28 NOTE: The material can be either starting material, intermediate material, or finished product (ISO 18113-1).
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batch all tubes, plates, or containers of a microbial identification system that have the same lot number and are received in a single shipment Project: M50
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batch code distinctive set of numbers and/or letters that specifically identifies a batch and permits its manufacturing,packaging, labeling, and distribution history to be traced (ISO 18113-1) Alternate Term: lot number Project: ISO CD 18112-1, ISO 18113-1, ISO 18113-2, ISO 18113-3
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battery a group of tests ordered together, for example, an admitting battery Project: LIS02 NOTE 1: The term "battery" is used in the document synonymously with the term "profile" or "panel"; NOTE 2: The test elements within a battery may be characteristic of a single physiologic system, for example, liver function tests, or many different physiologic systems; NOTE 3: The battery is simply a convention by which a user can order multiple tests by specifying a single name.
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battery a set of one or more laboratory tests, identified by a single name and code that can be ordered to a laboratory Project: AUTO16
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battlement pattern a method of studying a blood film in which the slide is moved from side to side (or end to end) over acceptable examination areas Project: H44 NOTE: The cumulative examination pathway resembles the battlement of a castle.
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B-cells (B lymphocytes) one of the two major populations of lymphocytes that display antigen-specific receptors and are involved in humoral immunity and antibody formation Alternate Term: B lymphocytes Project: NBS07, NBS06 NOTE 1: Normal B-cells can be transformed into continuous cell lines by the Epstein-Barr virus. NOTE 2: B-cell progenitors produced in bone marrow differentiate and mature in the bone marrow, spleen, and lymph nodes. During this process, the B-cell progenitors rearrange the regions of their genome containing variable and constant region genes to form sequences that code for the heavy and light chains of immunoglobulin that form their antigen-specific receptors and the secreted antibody.
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bead array created by either impregnating silica or polystyrene beads with different concentrations of fluorescent dye or by some type of bar-coding technology. The beads are addressable and used to identify specific binding events that occur on their surfaces Project: MM22
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bedside communication controller specifies the interface (principally input) to an access point or concentrator Project: POCT01 NOTE: This is an IEEE definition, equivalent to “access point interface.”
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bedside testing See point-of-care testing Alternate Term: point-of-care testing; near-patient testing Project: POCT13
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Beer’s law the mathematical relationship that defines the amount of radiant energy absorbed by a given substance concentration of a material Project: NRSCL8 NOTE: The concentration of a substance is directly proportional to the amount of light absorbed or inversely proportional to the logarithm of the transmitted light; A = e bc = log 100/%T = 2 - log %T; where A = absorbance; e = absorptivity; b = light path length; c = substance concentration; and %T = percent transmittance.
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benchmark a standard or measurement that is used to compare with other similar situations Project: QMS04, QMS12 Source: Quality Glossary
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beneficence the duty to do good and avoid harm to others Project: GP45 NOTE: The principle of beneficence requires that research design be scientifically sound and that the risks of the research be acceptable in relation to the likely benefits.
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benign sequence variation variations in the genome that are not associated with clinically recognized diseases
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benign variant a DNA sequence that is not associated with clinically recognized disease Project: NBS05
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best measurement capability the smallest uncertainty of measurement a laboratory can achieve for a stated calibration under specified laboratory conditions Project: C43
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beta error probability of falsely rejecting the alternative hypothesis when it is true Project: EP31
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beta error probability of not rejecting the null hypothesis when it is false Alternate Term: type II error Project: EP07 NOTE: See power.
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beta globulin one of several groups of blood plasma proteins, divided into fractions, based on electrophoretic mobility somewhat slower than alpha globulin Project: DI01
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beta hemolysis the production of a clear zone surrounding a bacterial colony on blood-agar medium, which is characteristic of certain pathogenic bacteria Project: POL1/2
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beta-actin (ACTB) gene the human gene for a nonmuscle cytoskeletal actin isoform Alternate Term: actin Project: NBS06 NOTE: A segment of the ACTB gene sequence is used as a genomic reference polymerase chain reaction product in some T-cell receptor excision circle assays.
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between-group design a study design in which comparisons are made between study subjects Project: GP45 NOTE 1: In observational studies, comparisons are made between two or more groups of study subjects with biological risk factors, environmental exposures, diagnoses, treatments, or use of health services; NOTE 2: In experimental studies, comparisons are made between two or more groups of study subjects who are allocated, ideally at random, to clinical treatments or the use of specific health services.
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between-subject variation variation in analyte concentrations among individuals because of differences in factors that cannot be altered within an individual or that last for an extended period of time Project: C48 NOTE: This includes factors such as age, sex, race, genetics, or long-term health status.
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between-unit homogeneity unit-to-unit variation of a property of a reference material Project: EP30 NOTE: The term “between-unit homogeneity” applies to all types of packages (eg, vials) and other physical shapes and test pieces.
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bias (of measurement) estimate of a systematic measurement error (JCGM 200:2012) Alternate Term: measurement bias Project: EP12, ISO IEC Guide 99, EP25, EP18, C43, H26, NBS04, MM06, H02, EP23, EP06, EP29, C56, EP27, EP26, C40, MM22, EP14, EP15, POCT13, EP19, MM21, QMS24, C24, NBS09, EP07, EP34, H48, MM10, C49, MM24, NBS05, NBS10 NOTE 1: In general, the deviation/difference is based on replicate measurement using an accepted (definitive, reference, or designated comparison) method and the method being tested and expressed in the units of the measurement or as a percentage; NOTE 2: In EP19, the metrological term “bias” is equivalent to the term “systematic difference”; NOTE 3: Difference between the expectation of a test result or measurement result and a true value; NOTE 4: In practice the accepted reference value is substituted for the true value; NOTE 5: Bias represents the quantitative expression of trueness; NOTE 6: Because trueness, the agreement between a measured value and a reference value, is a concept and cannot be expressed numerically, it is estimated using bias; NOTE 7: Bias at a specified concentration can be determined using the slope and intercept from a measurement procedure comparison regression; NOTE 8: In laboratory verification comparison studies using difference plots, when bias is relatively constant and in the same direction (positive or negative) within a specified measuring interval, bias can be expressed as an average over that specified interval; NOTE 9: The bias of a measuring instrument is normally estimated by averaging the error of indication over an appropriate number of repeated measurements; NOTE 10: The bias is the difference between the expectation of the test results and an accepted reference value (modified from ISO 5725-1); NOTE 11: The “accepted reference value” in Chapter 5 is the result from the same measurement procedure in the absence of the potentially interfering substance. In Chapter 7, it is the result from the comparative measurement procedure (ISO 5725-1); NOTE 12: See trueness; NOTE 13: When a value is obtained using a method other than a reference test method, the difference between biases of the methods is called a systematic difference. For simplicity, EP19 uses the term “bias” to refer to both situations; NOTE 14: For a qualitative, binary examination, bias is typically determined at the cutoff and expressed in terms of the instrument’s internal continuous response; NOTE 15: The difference between the expectation of the test results and an accepted reference value (modified from ISO 5725-1).
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bias the difference between the expectation of the test results and a true value (ISO 5725-1) Project: ISO 15197, ISO 17593, ISO 15198, ISO 5725-1, EP17, I/LA23, C58, C48, ISO 3534-1, ISO DIS 17593, MM12, H20, C50, H57, H26, GP34, MM20, H60, C57, POCT06, EP31, EP35 NOTE 1: Bias is the total systematic error, as contrasted to random error. There can be one or more systematic error components contributing to the bias. A larger systematic difference from the accepted reference value is reflected by a larger bias value (ISO 5725-1); NOTE 2: The measure of trueness is usually expressed in terms of bias (ISO 3534-1); NOTE 3: Bias is the numerical counterpart of trueness; NOTE 4: If the comparison method is a reference method, then the difference between the two methods measures the trueness of the new method, measured as bias. If the comparison method is not a reference method, then the trueness of the new method cannot be determined. In this case, one refers to the difference simply as a difference, and not bias; NOTE 5: Bias is a measure of trueness; NOTE 6: Bias applies to quantitative measurement procedures; NOTE 7: In the context of CLSI EP35, bias refers to the estimated bias at specific concentrations from a measurement procedure equivalence study; NOTE 8: In CLSI EP35, the metrological term systematic difference is related to the term “bias.”
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bias 1) lack of validity; the degree to which a study fails to measure what it is designed to measure, due to deviation of results or inferences from the truth, or processes leading to such deviation; 2) any trend in the collection, analysis, interpretation, publication, or review of data that can lead to conclusions that are systematically different from the truth. Ways in which this deviation from the truth can occur include: a) systematic (one-sided) variation of measurements from the true values (also known as “systematic error”); b) variation of statistical summary measures (means, rates, measures of association, etc.) from their true values as a result of systematic variation of measurements, other flaws in data collection, or flaws in study design or analysis; c) deviation of inferences from the truth as a result of flaws in study design, data collection, or the analysis or interpretation of results; d) a tendency of procedures (in study design, data collection, analysis, interpretation, review or publication) to yield results or conclusions that depart from the truth; e) prejudice leading to the conscious or unconscious selection of study procedures that depart from the truth in a particular direction or to one-sidedness in the interpretation of results Project: GP45 NOTE: Many different types of study bias have been described, including systematic distortion of the estimated intervention effect away from the “truth,” caused by inadequacies in the design, conduct, or analysis of a trial.
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bias (of measurements) difference between the expectation of the results of measurement and a true value of the measurand (ISO 17511) Project: ISO 17511 NOTE: An estimator is the "statistical sample bias of measurements," which is the "average minus its reference value" (ISO 17511).
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bias any systemic error in measurements provided by a measurement procedure or system. Often associated with the average error across a sample of measurement/reference pairs Project: POCT05
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bias 1) the difference between the expectation of a test result or measurement result and a true value (ISO 5725-1); 2) a quantitative measure of inaccuracy or systematic departure from accuracy under specified conditions of analysis Project: POCT14, POCT04 NOTE: Types of bias include: •interinstrument (between-instrument) – the difference between the results obtained using two specified instruments. •interlaboratory (between-laboratory) – the average difference between the results obtained by two different laboratories performing the same analytical process under specified conditions. •intermeasurement procedure (between-measurement procedure) – the difference between the results obtained by two specified measurement procedures. •of a result – the difference between the result and the true or expected value. •of an analytical process – the average difference between the results obtained by the analytical process in question under specified conditions of matrix, analyte concentration, etc., and the true or accepted result; synonym for “systematic error.”
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bias the difference between the expectation of the measurement procedure results and an accepted reference value (modified from ISO 3534-2) Project: EP33
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bias (of measurement) difference between the expectation of the test results and an accepted reference value (ISO 5725-1); estimate of a systematic measurement error (JCGM 200:2012) Project: EP09 NOTE 1: Because trueness, the agreement between a measured value and a reference value, is a concept and cannot be expressed numerically, it is estimated using bias; NOTE 2: Bias at a specified concentration can be determined using the slope and intercept from a measurement procedure comparison regression; NOTE 3: In laboratory verification comparison studies using difference plots, when bias is relatively constant and in the same direction (positive or negative) within a specified measuring interval, bias can be expressed as an average over that specified interval.
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bias (of measurement) difference between the expectation of a test result or measurement result and a true value (ISO 3534-2) Project: EP21, EP10, C62, EP46, POCT15 NOTE 1: Bias is an estimate of a systematic measurement error (JCGM 200:2012). Because trueness, the agreement between a measured value and a reference value, is a concept and cannot be expressed numerically, it is estimated using bias; NOTE 2: In some measurement procedure comparison studies, when bias is relatively constant and in the same direction (positive or negative), bias can be expressed as an average over the entire measuring interval; NOTE 3: Bias is the numerical counterpart of trueness.
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bias the systematic {signed} deviation of the test results from the accepted reference value Project: NRSCL08, C44 NOTE: In general, the deviation/difference is based on replicate measurement using an accepted (definitive, reference, or designated comparison) method and the method being tested, and expressed in the units of the measurement or as a percentage.
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bicarbonate (HCO3) a salt of carbonic acid, containing the HCO3-group Project: NRSCL8
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bicarbonate In clinical chemistry, the substance concentration of bicarbonate ion is reported in plasma, in equilibrium with fresh erythrocytes under specified conditions; cHCO-3= (ctCO2 - cCO2); LogcHCO -3= pH – pK'+ log PCO2+log aCO2 Project: C12, C27, C32 NOTE 1: This is not measured directly, rather, it is the result of one or more calculations based on measurement and/or assumptions of the substance concentration of total carbon dioxide, pH, and carbon dioxide tension in plasma under specified conditions; NOTE 2: The concentration of bicarbonate determined by the equations is that in plasma water (Cf. C12, C27, C32).
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bidding and negotiations fifth design phase of the construction project, in which the drawings and specifications are sent to the contractor for bids on the overall project cost Project: QMS04
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bidirectional bidirectional systems or devices can both send (results, quality control, etc.) from the devices to the observation reviewer and receive data (like operator lists) from the observation reviewer to the device, as opposed to devices that can only send results (unidirectional) Project: POCT02
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bidirectional interface a parallel interface that can transfer data in both directions; for example, the transfer of information from the laboratory information system or Blood Establishment Computer Software to the automated system and from the automated system back to the laboratory information system or Blood Establishment Computer Software Project: I/LA33 NOTE: See interface.
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binary output examination results that are reported as positive or negative, yes or no, or target condition present or absent Project: EP12-IG
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binding capacity within the context of I/LA20 and I/LA34, the binding capacity refers to the number of human immunoglobulin E antibody molecules that an allergen-containing reagent (eg, allergosorbent, liquid-phase allergen) can bind reproducibly under standardized assay conditions (pH, ionic strength, protein matrix, time, temperature) Project: I/LA34, I/LA20 NOTE: The binding capacity of a reagent is highly dependent on the number of immunoreactive allergen molecules and individual epitopes attached to the solid phase or present in the solution phase reagent. For manufacturers, the goal is to identify allergen-containing reagent preparation conditions that produce maximal binding of allergen to the reagent solid phase in a relevant and reproducible manner.
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binding capacity in Immunology, the capacity of a receptor, such as an antibody, to bind a ligand, such as an antigen Project: DI01
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biobank storage system for biological material (blood, tissue, or other) for the purpose of future scientific investigation, and traceable to the individual from whom it originates Project: PRE04
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biocide a chemical or physical agent that kills microorganisms Project: GP40
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biofilm microorganisms, enclosed in a glycoprotein/polysaccharide matrix, that adhere to each other and/or to surfaces and may form macroscopic layers Project: GP40
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biohazard a biological agent or condition that constitutes a hazard to human beings or their environment Project: AST02, HS02, POCT10, POCT04
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biohazard a biological agent or condition that constitutes a hazard to human beings, animals, or their environment Project: QMS04
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biohazard (biological hazard) a biological agent, material, or condition that constitutes a hazard to human beings or their environment Project: M29 NOTE: Potential source of harm caused by biological agents or toxins (CWA 15793).
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bioinformatic pipeline a series of software algorithms that process raw sequencing data and generate interpretations from the data Project: MM26
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bioinformatician an expert who combines research in biology, medicine, and health-related studies with information technology to interpret data covering fields such as genetics Project: MM26 NOTE: Bioinformaticians create and maintain databases of biological information and develop and use mathematical models for arithmetical analysis.
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biologic a drug that is prepared using a biological starting or source material (ie, derived from a microorganism, plant, or animal) and various manufacturing techniques Project: HS11
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biological agent any microorganism, including those which have been genetically modified, cell cultures and human endoparasites, which may be able to provoke any infection, allergy, or toxicity (ISO 15190) Project: ISO 15190, M29 NOTE 1: For classification of biological agents into risk groups, see Clause 4 of ISO 15190; NOTE 2: For the purposes of M40, proteinaceous infectious particles are regarded as “biological agents” (CWA 15793).
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biological analyte analyte composed of or derived from a specimen for use in spiking surrogate samples Project: EP39 EXAMPLES: Analyte-positive specimens; purified or extracted protein; DNA extracted from formalin-fixed, paraffin-embedded tissue specimens; analyte obtained from purified organisms; biological analyte reproduced from cell culture.
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biological matrix components of a material system, except the analyte (modified from ISO 17511) Project: EP39 NOTE: The biological matrix is the milieu in which the analyte exists in a given sample (eg, serum, urine).
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biological product a substance that originated from living organisms (including humans and other mammals) and has been manufactured and distributed in accordance with compliance and licensing requirements set forth by the federal government; can be classified as an infectious substance if such is appropriate Project:
M29 NOTE: Biological products are intended for use in the prevention, treatment, or diagnosis of disease in humans or animals and may be used for investigational, experimental, or development purposes.
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biological reference interval specified interval of the distribution of values taken from a biological reference population (ISO 15189, ISO 18113-1) Alternate Term: reference interval Project: ISO 15189, I/LA02, ISO 18113-1, EP39, NBS10 EXAMPLE: The 0.95 biological reference interval for sodium ion concentration values in serum from a population of healthy male and female adults is 135 to 145 mmol/L (ISO 18113-1); NOTE 1: A reference interval is commonly defined as the central 95% interval. Another size or an asymmetrical location of the reference interval could be more appropriate in particular cases (ISO 15189, ISO 18113-1); NOTE 2: A reference interval can depend upon the type of primary samples and the examination procedure used (ISO 18113-1); NOTE 3: In some cases, only one biological reference limit is important, usually an upper limit, “x,” so that the corresponding biological reference interval would be less than or equal to “x” (ISO 18113-1); NOTE 4: Terms such as “normal range,” “normal values,” and “clinical range” are ambiguous and therefore discouraged (ISO 15189, ISO 18113-1); NOTE 5: Adapted from: CLSI document C28; International Federation of Clinical Chemistry, International Committee for Standardization in Haematology. Approved recommendation (1986) on the theory of reference values. Part 1. Theconcept of reference values. Clin Chim Acta. 1987;167:111-118; International Federation of Clinical Chemistry, International Committee for Standardization in Haematology. Approved recommendations (1987) on the theory of reference values. Part 5. Statistical treatment of collected reference values. Determination of reference limits. J Clin Chem Clin Biochem. 1987;25:645-656; and Poulsen OM, Holst E, Christensen JM. Calculation and application of coverage intervals for biological reference values (technical report) — A supplement to the approved IFCC recommendation (1987) on the theory of reference values. Pure Appl Chem. 1997;69(7)1601-1611 (ISO 18113-1); NOTE 6: Interval between, and including, the lower reference limit and the upper reference limit of the reference population; NOTE 7: For genomic copy number microarrays, the range of copy number variants and absence of heterozygosity that occur in the normal healthy population. Also see reference range; NOTE 8: A biological reference population is a homogeneous population of individuals in a well-defined state of health or disease, which can be a defined group of apparently healthy individuals or individuals with a specific medical condition. The concept enables relating the reference interval to age, sex, and ethnicity of the reference population, as appropriate; NOTE 9: The term “reference interval” is preferred over “reference range”; the latter term should be used to refer only to the difference between the upper and lower limits of an interval;
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biological reference interval interval between, and including, the lower reference value limit and the upper reference value limit of the biological reference population Alternate Term: reference interval Project: ISO/CD 18113-1, ISO/CD 18113-2, ISO/CD 18113-3, POCT17 EXAMPLE: The biological reference interval for glucose measurements in plasma from fasting subjects in a population of healthy male and female adults is from 3.6 to 6.1 mmol/L; NOTE 1: A biological reference population is a homogeneous population of individuals in a well-defined state of health or disease, which can be a defined group of apparently healthy individuals or individuals with a specific medical condition. The concept allows for relating the reference interval to age, gender, and ethnicity of the reference population, as appropriate; NOTE 2: The type of samples used to determine the reference intervals and the examination procedure used for their determination should be reported; NOTE 3: Biological reference intervals in clinical and occupational medicine are conventionally defined as a 0.95 coverage interval with a confidence of 0.95, which serves as a prediction interval where the probability of a future observation from the distribution being included in the interval is equal to the expectation. Consequently, an observation outside the coverage interval can be considered unusually high (or low), and further scrutiny is needed to establish whether the patient is at increased health risk; NOTE 4: In some cases, only one biological reference limit is important, usually an upper limit, “x,” and the corresponding biological reference interval would be less than or equal to “x”; NOTE 5: Terms such as “normal range” and “normal values” are considered obsolete. [IFCC]
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biological reference population group of individuals in a well-defined state of health or disease (ISO 18113-1)
Alternate Term: reference population Project: ISO 18113-1 NOTE 1: When biological reference intervals are provided by a manufacturer in the instructions for use, laboratories using the IVD medical device are responsible for verifying that the biological reference populations represent the populations serviced by the laboratories (ISO 18113-1); NOTE 2: A biological reference population can be a defined homogenous group of apparently healthy individuals or individuals with a specific medical condition. The concept allows for relating the reference interval to age, gender and ethnicity of the reference population, as appropriate (ISO 18113-1); NOTE 3: Adapted from: CLSI document C28; International Federation of Clinical Chemistry, International Committee for Standardization in Haematology. Approved recommendation (1986) on the theory of reference values. Part 1. Theconcept of reference values. Clin Chim Acta. 1987;167:111-118; International Federation of Clinical Chemistry, International Committee for Standardization in Haematology. Approved recommendations (1987) on the theory of reference values. Part 5. Statistical treatment of collected reference values. Determination of reference limits. J Clin Chem Clin Biochem. 1987;25:645-656; and Poulsen OM, Holst E, Christensen JM. Calculation and application of coverage intervals for biological reference values (technical report) — A supplement to the approved IFCC recommendation (1987) on the theory of reference values. Pure Appl Chem. 1997;69(7)1601-1611 (ISO 18113-1).
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biological safety describes the containment principles, technologies, and practices that are implemented to prevent the unintentional exposure to biological agents and toxins or their accidental release (CWA 15793) Alternate Term: biosafety Project: M29
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biological safety cabinet hood designed specifically to contain microorganisms Alternate Term: biosafety cabinet Project: QMS04 NOTE 1: They are designed to protect workers, the environment, and laboratory consumables from contamination; NOTE 2: They can also be designed to use small amounts of chemicals and to keep products in the hood clean.
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biological safety cabinet See microbiological safety cabinet
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biological safety cabinet a ventilated cabinet for personnel, product, and environmental protection having an open front with an inward airflow for personnel protection, downward high-efficiency particulate air–filtered laminar airflow for product protection, and high-efficiency particulate air–filtered exhausted air for environmental protection Alternate Term: biosafety cabinet Project: M29
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biological safety level combinations of laboratory practices and techniques, safety equipment, and laboratory facilities. Each combination is specifically appropriate for the performed operations, the documented or suspected routes of transmission of the infectious agents, and the laboratory function or activity Alternate Term: biosafety level Project: M29, GP36
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biological select agents and toxins See select agent Alternate Term: select agent Project: M29
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biological substance, Category B any infectious substance that does not meet the criteria of a Category A substance; an infectious substance not in a form generally capable of causing disability, life-threatening illness, or fatal disease Alternate Term: Category B, biological substance Project: M29 NOTE 1: Category B substances generally are 1) patient and clinical specimens reasonably expected to contain a non–Category A pathogen; and 2) cultures of microorganisms not specifically listed in Category A; NOTE 2: The United Nations number and proper shipping name for a Category B substance is Biological Substance, Category B.
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biological variation consists of within-subject (intraindividual) and between-subject (interindividual, group) variation Project: EP33
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biomarker a characteristic or compound that is objectively measured and evaluated as an indicator of normal biologic or pathogenic processes or pharmacologic responses to a therapeutic intervention Project: C50 NOTE: In the context of C50, a biomarker is a chemical entity that can be quantified, and in which there is a relationship between the amount of that entity and some pathogenic, pharmacologic, or therapeutic event.
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biomarker a specific analyte (eg, DNA, RNA, protein) found in a patient specimen that is useful for measuring the progress of disease or the effects of treatment or for diagnosis or exclusion of disease Project: MM13, MM23
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biomarker any feature of a patient that is useful for measuring the risk of developing, presence, or progression of disease or the effects of treatment Project: I/LA28 NOTE: Frequently, biomarkers are biomolecules (proteins, nucleic acids, or other biomolecules) that are obtained from the patient and subject to direct analysis.
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biomarker a compound that is objectively measured and evaluated as an indicator of normal biological or pathogenic processes or pharmacological responses to a therapeutic intervention Project: NBS04, NBS09 NOTE 1: In the context of NBS04, a biomarker is a chemical entity that can be quantified and in which there is a relationship between the amount of that entity and some pathogenic, pharmacological, or therapeutic event; NOTE 2: Also called “marker”; NOTE 3: A chemical entity that can be quantitated and in which there is a relationship between the amount of that entity and some pathogenic, pharmacological, or therapeutic event; NOTE 4: See primary markers and secondary markers.
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biomass biological material from organisms Project: M58 NOTE: In the context of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for microorganism identification, “biomass” refers to the microorganisms themselves.
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biometrics the measurement and analysis of unique physical characteristics of an individual (eg, fingerprints, voice pattern, retinal scan) as a means of verifying personal identity Project: AUTO11
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biopolymers a macromolecule in a living organism that is formed by linking together several smaller molecules (eg, DNA, RNA, polysaccharides, proteins, and peptides) Project: C50
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biopsy the medical removal of tissue from a living subject to determine the presence or extent of a disease Project: MM23
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biorepository a repository or storage facility or archive of biological specimens including tissue, serum, plasma, and other fluids Project: I/LA28
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biosafety See biological safety Alternate Term: biological safety Project: M29
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biosafety cabinet See biological safety cabinet Alternate Term: biological safety cabinet Project: M29
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biosafety level (BSL) combinations of laboratory practices and techniques, safety equipment, and laboratory facilities. Each combination is specifically appropriate for the performed operations, the documented or suspected routes of transmission of the infectious agents, and the laboratory function or activity Project: QMS04 NOTE 1: This is subdivided into four levels (BSL-1, BSL-2, BSL-3, BSL-4) for microbiological and biomedical laboratories; NOTE 2: In the United States and Europe, this is subdivided into four levels (BSL-1, BSL-2, BSL-3, BSL-4) for microbiological and biomedical laboratories.
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biosafety level See biological safety level Alternate Term: biological safety level Project: M29, GP36
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biosafety level 1 (Canadian, containment level 1 laboratory) practices, safety equipment, and facility design and construction for work involving well-characterized agents not known to consistently cause disease in healthy adult humans, and of minimal potential hazard to laboratory personnel and the environment NOTE 1: It includes several kinds of bacteria and viruses including canine hepatitis, nonpathogenic Escherichia coli, as well as some cell cultures and noninfectious bacteria; NOTE 2: At this level, precautions against the biohazardous materials in question are minimal, most likely involving gloves and some sort of facial protection.
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biosafety level 2 practices, safety equipment, and facility design and construction that are applicable to clinical, diagnostic, teaching, and other laboratories in which work is done with the broad spectrum of indigenous moderate-risk agents that are present in the community and associated with human disease of varying severity Project: GP36
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biosafety level 2 (Canadian, containment level 2 laboratory) practices, safety equipment, and facility design and construction for work involving agents of moderate potential hazard to personnel and the environment NOTE 1: It includes various bacteria and viruses that cause only mild disease to humans, or are difficult to contract via aerosol in a laboratory setting, such as Clostridium difficile; hepatitis A, B, and C; influenza A; Lyme disease; dengue fever; Salmonella; mumps; measles; human immunodeficiency virus; scrapie; methicillin-resistant Staphylococcus aureus; and vancomycin-resistant S. aureus; NOTE 2: Genetically modified organisms have also been classified as biosafety level 2 organisms, even if they pose no direct threat to humans. This designation is used to limit the release of modified organisms into the environment. In the United States, US Food and Drug Administration approval is required to release these organisms.
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biosafety level 3 practices, safety equipment, and facility design and construction that are applicable to clinical, diagnostic, teaching, research, or production facilities in which work is done with indigenous or exotic agents with a potential for respiratory transmission, and which may cause serious and potentially lethal infection Project: GP36
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biosafety level 3 (Canadian, containment level 3 laboratory) practices, safety equipment, and facility design and construction that are applicable to clinical, diagnostic, teaching, research, or production facilities in which work is done with indigenous or exotic agents with a potential for respiratory transmission, and which may cause serious and potentially lethal infection NOTE: It includes various bacteria and viruses that can cause severe to fatal disease in humans, but for which vaccines or other treatment exist, such as Mycobacterium tuberculosis, Bacillus anthracis, West Nile virus, Venezuelan equine encephalitis virus, Eastern equine encephalitis virus, Hendra virus, severe acute respiratory syndrome coronavirus, Coxiella burnetii, Rift Valley fever virus, Rickettsia rickettsii, and yellow fever virus.
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biosafety level 4 practices, safety equipment, and facility design and construction that are required for work with dangerous and exotic agents that pose a high individual risk of aerosol-transmitted laboratory infections and life-threatening diseases that are frequently fatal and for which there are no vaccines or treatments or a related agent with unknown risk of transmission Project: GP36
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biospecimen a biological sample fluid or tissue obtained from an organism Project: I/LA28
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bioterrorism biological diseases and the select agents that might be used for terrorism Project: QMS04 NOTE: Select agents are very varied and comprise viruses, bacteria, rickettsiae (microorganisms that have traits common to both bacteria and viruses), fungi, and biological toxins.
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biotin a molecule that can be covalently attached to lysine residues of proteins Project: NRSCL8 NOTE: This property is used in many detection systems.
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biotin a 241-dalton molecule that can be attached covalently to lysine residues of proteins Project: I/LA28 NOTE 1: Owing to its small size, it has minimal impact on the protein to which it is conjugated. The proteins avidin and streptavidin have a high affinity for biotin; NOTE 2: This property can be used in many detection systems.
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biphasic blood culture system a blood culture system in which a single container (eg, vial) has separate chambers for solid- and liquid-based media Project: M47
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birth prevalence the number of times a congenital disease is confirmed in a baby, as a fraction of the number of babies born alive Project: NBS10 Source: Newborn Screening Glossary NOTE 1: “Incidence” is not the same as “birth prevalence,” because incidence refers to the occurrences of a disease over time; NOTE 2: “Birth prevalence” should not be confused with “prevalence,” which is a measure of the total number of existing cases of a disease or condition as a fraction of a defined population.
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blank sample that does not contain the analyte of interest, or has a concentration at least an order of magnitude less than the lowest level of interest Project: EP17, H58 NOTE: In the context of H58, in most cases, this is platelet-poor plasma.
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blank (nontemplate control) the apparent amount or concentration of an analyte measured by an analytical process when an analyte is omitted from a tested sample or when the tested sample is known to contain none of the analyte; a combination of the individual “blanks,” such as the extraction blank and the reagent blank, as appropriate for the assay Project: NRSCL8, MM10, MM03, MM24
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blank (no template control) the apparent amount or concentration of a measurand measured by an analytical process when a measurand is omitted from a tested sample or when the tested sample is known to contain none of the measurand; a combination of the individual “blanks,” such as the extraction blank and the reagent blank, as appropriate for the assay Project: MM22
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blank indication indication obtained from a phenomenon, body, or substance similar to the one under investigation, but for which a quantity of interest is supposed not to be present, or is not contributing to the indication (JCGM 200:2012) Alternate Term: background indication Project: ISO IEC Guide 99
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blastoconidium (pl. blastoconidia) a conidium that is formed by budding from a hyphal, pseudohyphal, or yeast cell Project: M54
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blind subculture subculture performed as a routine laboratory procedure irrespective of any objective evidence of microbial growth Project: M47
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blind subpassage transfer of cells and/or medium from an existing viral culture to a fresh cell culture monolayer(s) Project: M41
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blinding the practice of keeping the trial participants, care providers, those collecting data, and sometimes even those analyzing data unaware of which intervention is being administered to which participant Alternate Term: masking Project: GP45 NOTE 1: Blinding is intended to prevent bias on the part of study personnel; NOTE 2: A very common application is “double-blinding,” in which participants, caregivers and investigators, and those collecting data are blinded to knowledge of the intervention that is administered; in “triple blinding,” those persons assessing outcome and analyzing the outcomes are blinded to intervention assignment.
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block cipher an encryption algorithm that breaks plaintext into fixed-size segments and uses the same key to transform each plaintext segment into a fixed-size segment of ciphertext (See stream cipher) (RFC 2828) Project: AUTO09
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block diagram graphic illustration of the spaces in a project and how they might fit into a designated area in the facility Project: QMS04 NOTE: This diagram is the very rough beginning of a floor plan.
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blocking the reaction of uncomplexed binding sites or of coupling agents to prevent nonspecific binding of test reactants Project: MM04
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blocking any inhibition of reaction that possibly may have occurred in the assay that would have resulted in inferior assay signal or result Project: I/LA28 NOTE: Examples of blocking reaction include; 1) the reaction of endogenous peroxidase in a tissue specimen with the intent of destroying enzyme activity; and 2) blocking of nonspecific binding of antibody reagents.
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blood the circulating intravascular tissue of the body, consisting of suspended formed elements and fluid plasma Project: ISO 17593, POCT04 NOTE: In ISO 17593, the term refers to fresh, nonanticoagulated blood.
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blood the “circulating tissue” of the body that consists of plasma in which are suspended cells, nutrients, metabolic products, and oxygen
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blood (occult) blood present in very small amounts; usually detectable by chemical means; specimen is most often stool; may or may not be related to parasitic infection Project: M28
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blood (venous) blood collected after directly puncturing a vein, usually with a needle and syringe, or other collection device; venous blood may be collected without additives such as anticoagulants or preservatives, and if so, will be inherently unstable; venous blood may also be collected into containers containing additives or preservatives with the intent to stabilize specific components Alternate Term: venous blood specimen Project: ISO CD 17593
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blood (capillary) blood collected after puncturing any of the minute vessels that connect the arterioles and venules, often obtained by pricking a fingertip; capillary blood is usually collected without additives such as anticoagulants or preservatives; therefore, it is inherently unstable Alternate Term: capillary blood specimen Project: ISO CD 17593, ISO/DIS 17593
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blood circulating intravascular component of the body, consisting of suspended formed elements and fluid plasma (modified from ISO 17593) Project: POCT13 NOTE: In ISO 17593, the term refers to fresh, nonanticoagulated whole blood.
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blood collection device a capped tube that contains a vacuum (otherwise known as an evacuated tube) usually held by an adaptor with an attached needle, syringe, or other device with a nonactivating surface used to collect a blood sample with the use of a needle assembly Project: H21
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blood collection system a system consisting of several components, such as catheter, connecting device, syringe, needle, and collection device, used for blood collection Project: H21
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blood culture a specimen of blood that is submitted for bacterial or fungal culture Project: M47 NOTE: A single blood culture specimen may be divided or distributed into more than one bottle or tube.
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blood culture series a group of temporally related blood cultures that are obtained to determine whether a patient has bacteremia or fungemia Project: M47
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blood culture set the combination of blood culture bottles or tubes into which a single blood specimen is inoculated Project: M47
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Blood Establishment Computer Software the software that is part of a blood establishment computer system, which is used by blood establishments (human blood and plasma donor centers, blood banks, transfusion services and other blood product manufacturers, and independent laboratories) in the manufacture and/or transfusion of blood and blood components Project: I/LA33 NOTE 1: It is designed to receive and store data used by blood establishments during the manufacturing process, from determining donor suitability through component processing, testing, and labeling to product release. It is designed to receive and store data regarding blood donor status, including donors’ answers to health history questions and the results of laboratory tests, such as blood grouping and typing, hepatitis, and antibody to HIV. Blood establishment personnel later access and use the data to determine if donors are suitable and if blood or blood components are free from disease-causing agents transmissible by blood, such as hepatitis and HIV. In addition, the data are used to label blood and blood components prior to release for use in hospitals and other health care facilities or for further manufacturing; NOTE 2: This software may be manufactured either in-house or by a software manufacturer or vendor; NOTE 3: For the purposes of this document, references to the laboratory information system can be interpreted to mean Blood Establishment Computer Software, as appropriate.
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blood glucose meter component of a blood-glucose monitoring system that converts the result of a chemical reaction into the glucose concentration of the sample (modified from ISO 15197) Project: ISO 15197, POCT07
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blood glucose monitoring system measuring system consisting of a portable instrument and reagents used for the in vitro monitoring of glucose concentrations in blood Project: ISO 15197 NOTE: Blood glucose monitoring systems measure glucose in capillary blood samples, but may express results as either the glucose concentration in blood or the equivalent glucose concentration in plasma. Concentrations in this International Standard refer to the type of results reported by the system (modified from ISO 15197).
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blood specimen (venous) blood collected after directly puncturing a vein, usually with a needle and syringe, or other collection device or from an indwelling catheter or line (modified from ISO 17593) Project: POCT13, POCT17
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blood specimen (arterial) blood obtained by arterial puncture or from an individual arterial line, catheter, or extracorporeal circuit Project: POCT13, POCT17
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blood specimen the discrete portion of blood taken for examination, study, or analysis of one or more quantities or characteristics to determine the character of the whole Project: POCT14, POCT13, POCT17 NOTE: Arterial blood is obtained by arterial puncture or from an individual arterial line, catheter, or extracorporeal circuit. Capillary blood is obtained by capillary puncture; the most commonly used capillary collection site is the finger. Venous blood is obtained by venipuncture or from an indwelling line or catheter.
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blood specimen (capillary) blood collected after puncturing any of the minute vessels that connect the arterioles and venules, often obtained by pricking a fingertip; capillary blood is usually collected without additives such as anticoagulants or preservatives, therefore, it is inherently unstable (modified from ISO 17593) Project: POCT13, POCT17
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bloodborne pathogens pathogenic microorganisms that are present in human blood and can cause disease in humans (29 CFR 1910.1030) Project: X3, M29 NOTE: These pathogens include, but are not limited to, hepatitis B virus, hepatitis C virus, and HIV.
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bloodborne pathogens pathogenic microorganisms that are present in human blood, blood products, or other potentially infectious material contaminated with blood, and can cause disease in humans or animals
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bloodstream infection an infection associated with bacteremia or fungemia Project: M47
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body fluid testing measurement of measurand(s) in biological specimens for which no performance claims from the measurement procedure’s manufacturer are available Project: C49
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bone alkaline phosphatase an enzyme found in osteoblasts Alternate Term: bone ALP Project: C48 NOTE 1: It has a molecular weight of approximately 140 000 Da; NOTE 2: It is distinguishable from other alkaline phosphatases by its oligosaccharide side chain.
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bone formation the deposition of new bone, including bone mineral and bone matrix components Project: C48
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bone marker biochemical substance produced or released during bone turnover Project: C48 NOTE: It can be measured in urine, blood, or other body fluids.
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bone resorption the process of removal of bone tissue, including bone mineral and bone matrix components Project: C48
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Boolean logic developed by George Boole in the mid-1800s, operates on a set of rules that provides a consistent output based on a predefined set of input parameters Project: AUTO10 NOTE: The rules can be easily defined in a set of logic tables or diagrams. The most common rules are AND, OR, NAND, and NOR logic statements.
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bootstrap a way of testing the reliability of a dataset; a statistical method for obtaining an estimate of error that is used to evaluate the reliability of a phylogenetic tree Project: MM10
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borderline antimicrobial susceptibility test interpretive category an interpretive category applicable only to certain results obtained with MTBC isolates tested against pyrazinamide by the radiometric instrument method (refer to the manufacturer’s package insert) NOTE: Repeat testing may determine whether the isolate in question is susceptible or resistant.
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borderline positive a test result that is neither positive nor negative, and thus the test has to be repeated or the results verified or extended by a confirmatory assay Project: I/LA18
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borderline result a term sometimes used for an out-of-range screening result that is close to a program-established screen-positive cutoff value and that indicates moderate risk/possible disease, rather than high risk/probable disease Project: NBS02, NBS13, NBS10 Source: Newborn Screening Glossary NOTE 1: A screen-positive result in the borderline range is typically followed up with a request for an additional screening specimen, rather than diagnostic testing or clinical evaluation; NOTE 2: Follow-up actions for a borderline result usually take additional time and should be restricted to diseases for which diagnosis and treatment are not time critical; NOTE 3: When a borderline result is obtained for the second time, the patient might be referred for diagnostic testing and/or clinical evaluation, rather than specimen collection for another screen; NOTE 4: See screen positive and repeat screening (requested); NOTE 5: In CLSI NBS10, see Figures 1 and 2.
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bottom of cap the farthest point from the top of the container/test tube that the cap reaches Project: AUTO01, AUTO07, AUTO02, AUTO12 NOTE: This point may be inside the tube.
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bottom of container the portion of the container/test tube farthest from the cap Alternate Term: bottom of tube Project: AUTO01, AUTO07, AUTO02, AUTO12
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bottom of tube See bottom of container Project: AUTO02, AUTO12
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bound fraction the fraction of total analyte bound to receptor Project: LA01
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bound ratio in Immunology, the ratio of receptor-bound to nonreceptor-bound (free), labeled analyte in an immunoassay Alternate Term: free ratio, bound fraction, free fraction Project: DI01
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boundary as used in this document, an absolute limit to the measurement response reading from an instrument Project: I/LA24 NOTE 1: Boundaries apply particularly to digitized data expressed in histograms, where the zero channel and the maximum channel define absolute limits to the readings obtained from the instrument; NOTE 2: Boundaries for fluorescence intensity calibration curves are often expressed in units of analyte dose as extrapolated from a calibration curve to the minimal or maximal possible reading on the instrument scale; lower boundary - the analyte dose extrapolated from a calibration curve to the lowest possible reading from an instrument; NOTE 3: The lower boundary is a theoretical value and should not be taken as a true measurement of instrument sensitivity. However, the actual sensitivity of the instrument can never be less than the lower boundary.
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breakage loss of vessel integrity due to the production of unintentional cracks or openings in the vessel’s walls Project: M40
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breakpoint (BP) specific values of parameters, such as MICs, on the basis of which bacteria can be assigned to the clinical categories "susceptible," "intermediate," and "resistant" (ISO 20776-1) Project: ISO 20776-1, ISO 20776-2 NOTE: For current interpretive breakpoints, reference can be made to the latest publications of organizations employing this reference method (eg, CLSI and EUCAST) (ISO 20776-1).
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breakpoint minimal inhibitory concentration or zone diameter value used to categorize an organism as susceptible, susceptible-dose dependent, intermediate, or resistant Project: VET09 NOTE 1: In CLSI VET09, “breakpoints” refers to clinical breakpoints, which is the phrase used in some jurisdictions to refer to thresholds used to categorize bacterial isolates in terms of clinical predictions; NOTE 2: Breakpoints are only approved for treatment or control purposes; NOTE 3: See interpretive category (for breakpoints), control//metaphylaxis, and treatment.
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breakpoint minimal inhibitory concentration/minimal effective concentration or zone diameter value used to categorize an organism as susceptible, susceptible-dose dependent, intermediate, nonsusceptible, or resistant Project: M38 NOTE 1: Minimal inhibitory concentration or zone diameter values generated by a susceptibility test can be interpreted based upon established breakpoints; NOTE 2: See interpretive category.
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breakpoint minimal inhibitory concentration or zone diameter value used to categorize an organism as susceptible, susceptible-dose dependent, intermediate, resistant, or nonsusceptible Project: M100, M39, VET02, M02, M07, M23, VET01, M44 Source: Microbiology Glossary NOTE 1: Minimal inhibitory concentration or zone diameter values generated by a susceptibility test can be interpreted based on established breakpoints; NOTE 2: See interpretive category (for breakpoints); NOTE 3: Also known as “clinical breakpoint”; NOTE 4: Because breakpoints are largely based on pharmacologically and clinically rich datasets using in vitro and in vivo data, they are considered robust predictors of likely clinical outcomes.
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breakpoint minimal inhibitory concentration (MIC) or zone value used to categorize an organism as susceptible, intermediate, resistant, or nonsusceptible Project: M24, M11 NOTE 1: MIC or zone diameter values generated by a susceptibility test can be interpreted based on established breakpoints; NOTE 2: See interpretive category (for breakpoints); NOTE 3: Also known as a "clinical breakpoint"
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breakpoint test (BPT) test that has the principal objective to provide categorical results (SIR) (ISO 20776-2) Project: ISO 20776-2 NOTE: This can include limited range dilution tests or diffusion tests (ISO 20776-2).
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breakthrough bacteremia bacteremia that persists while a patient is receiving antimicrobial therapy for an episode of bacteremia NOTE 1: Breakthrough bacteremia that occurs early usually is the result of inappropriate or inadequate antimicrobial therapy; NOTE 2: Breakthrough bacteremia that occurs late usually is the result of a focus of infection (eg, an abscess) that has not been drained adequately.
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brefeldin A a relatively nontoxic but potent protein inhibitor of intracellular protein transport Project: I/LA26
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British thermal unit the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit Project: QMS04 NOTE: This measurement is used to describe the heating or cooling capacity of a system.
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broker a consultant, contractor, or waste transport firm that evaluates waste material, determines the appropriate disposal method, and makes arrangements for transport and disposal Project: GP05
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broth fluid medium used for the in vitro growth of bacteria (ISO 20776-1) Project: ISO 20776-1
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broth dilution technique in which containers are filled with appropriate volumes of an antimicrobial solution, employing incrementally (usually two-fold) increasing concentrations of the antimicrobial agent and appropriate volumes of broth with a defined inoculum (ISO 20776-1) Project: ISO 20776-1 NOTE: The aim of this method is the determination of the MIC (ISO 20776-1).
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broth dilution susceptibility test an in vitro antimicrobial susceptibility test conducted using serial concentrations of an antimicrobial agent incorporated into a liquid nutrient medium that are inoculated with a bacterial suspension to determine the minimal inhibitory concentration of the antimicrobial agent Project: VET02 NOTE: When this procedure is performed in test tubes, it is referred to as broth macrodilution; when performed in microdilution plates, it is called broth microdilution.
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broth dilution susceptibility test an antimicrobial susceptibility test conducted using serial concentrations of an antimicrobial agent incorporated into a broth growth medium, in separate test tubes or in the wells of a microtitration tray
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broth dilution susceptibility test an in vitro antimicrobial susceptibility test conducted using serial concentrations of an antimicrobial agent incorporated in liquid nutrient media that are inoculated with a bacterial suspension to determine the minimal inhibitory concentration of an antimicrobial agent Project: VET05 NOTE: When this procedure is carried out in test tubes, it is referred to as broth macrodilution; when performed in microdilution plates, it is called broth microdilution.
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broth microdilution technique the method of antimicrobial susceptibility testing that is based on preparation of a liquid broth medium containing various concentrations of antimicrobial agents into which a defined inoculum of microorganisms is inoculated and then incubated and observed for growth Project: M43
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bubble diagram graphic illustration, using circles, of the required relationships between various spaces in a project Project: QMS04
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buffer a solution or reagent that can resist a change in pH upon addition of either an acid or a base Project: MM04, I/LA28
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buffy coat a yellowish-white layer of leukocytes and platelets that forms on top of the column of red blood cells upon centrifugation of whole blood Project: NRSCL8 NOTE 1: Defined by WHO-BS/95.1793 as "a blood component rich in leukocytes and platelets, suspended in a small volume of plasma from the same donation"; NOTE 2: It is obtained either by separation from whole blood or by cytopheresis.
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buffy coat the fraction of a centrifuged blood sample that contains most of the white blood cells NOTE: After centrifugation, one can distinguish a layer of clear fluid (the plasma), a layer of red fluid containing most of the red blood cells, and a thin layer in between, the buffy coat (so-called because it is usually buff in hue), with most of the white blood cells and platelets. The buffy coat is used, for example, to extract DNA from the blood of mammals (since mammalian red blood cells do not contain DNA).
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building commissioning the process of verifying that all systems for heating, ventilation, and air conditioning; plumbing; electrical; controls; fire; security; building envelope; and interior materials meet the owner’s requirements as designed by the owner’s design team Project: QMS04
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built-in anything incorporated into the measuring system by the manufacturer Project: EP23
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business continuity planning the creation and validation of a practiced logistical plan for how an organization will recover and restore partially or completely interrupted critical (urgent) functions within a predetermined time after a disaster or extended disruption
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C5 value in a relevant scale (eg, an internal continuous response) where a binary examination declares a sample to be positive 5% of the time Project: EP12, EP12-IG NOTE: Like precision, C5 is associated with stipulated precision conditions.
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C50 the analyte concentration near the cutoff that yields 50% positive results and 50% negative results when many replicates of a single sample at that concentration are tested
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C95 value in a relevant scale (eg, an internal continuous response) where a binary examination declares a sample to be positive 95% of the time Project: EP12, EP12-IG NOTE: Like precision, C95 is associated with stipulated precision conditions.
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calcium ion-selective membrane the active element of the ion-selective membrane half-cell that responds to changes in activity of calcium ion in solution Project: C39 NOTE: A calcium ion-selective membrane typically contains an ionophore or ion-exchanger and a plasticizer in a plastic matrix such as polyvinyl chloride or polyurethane; other additives may be included to improve membrane functionality.
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calibrated assays three levels of calibrated immunoglobulin E antibody assays are proposed as follows: 1) titration assays that use an arbitrary reference system to define a class or arbitrary value; this category of calibration can reliably discriminate between doubling dilutions, but it does not ensure parallelism; 2) calibrated titration assays, such as immunoglobulin E antibody assays that are calibrated with a heterologous serum immunoglobulin E dose-response curve and that generate reliable, reproducible results; these assays behave consistently with respect to parallelism; 3) quantitative assays as represented by the total serum immunoglobulin E assay but which are not commercially available for immunoglobulin E antibody quantification NOTE: These are assays that use a homologous calibrator. They produce reproducible and accurate results, and behave appropriately with respect to parallelism and recovery. The number of calibrators must be in context to the measurement system. Factory-calibrated procedures, which are often stored in random access memory, may have one or more “adjusters” that normalize response data and can reproducibly and accurately determine analyte concentrations for many immunoassay runs.
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calibrated assays the proposed three levels of calibrated immunoglobulin E antibody assays are: 1) titration assays that use an arbitrary reference system to define a class or arbitrary value; this category of calibration can reliably discriminate between doubling dilutions, but it does not ensure parallelism; 2) calibrated titration assays, such as immunoglobulin E antibody assays that are calibrated with a heterologous serum immunoglobulin E dose-response curve and that generate reliable, reproducible results; these assays behave consistently with respect to parallelism; 3) quantitative assays as represented by the total serum immunoglobulin E assay but which are not commercially available for immunoglobulin E antibody quantification Project: I/LA20 NOTE: Quantitative assays use a homologous calibrator. They produce reproducible and accurate results, and behave appropriately with respect to parallelism and recovery. The number of calibrators must be in context with the measurement system. Factory-calibrated procedures, which are often stored in random access memory, may have one or more “adjusters” that normalize response data and can reproducibly and accurately determine analyte concentrations for many immunoassay runs.
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calibrated assays two levels of calibrated immunoglobulin E antibody assays are proposed as follows: 1) titration assays that use an arbitrary reference system to define a class or arbitrary value; this category of calibration can reliably discriminate between doubling dilutions, but it does not ensure parallelism; 2) calibrated titration assays, such as immunoglobulin E antibody assays that are calibrated with a heterologous serum immunoglobulin E dose-response curve and which generate reliable, reproducible results; these assays behave consistently with respect to parallelism Project: I/LA34
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calibration operation that, under specified conditions, in a first step, establishes a relation between the quantity values with measurement uncertainties provided by measurement standards and corresponding indications with associated measurement uncertainties and, in a second step, uses this information to establish a relation for obtaining a measurement result from an indication (JCGM 200:2012) Project: ISO IEC Guide 99, ILA29, H58, EP25, POCT09, ISO 18113-1, H26, H59, M53, C58, MM19, MM01, EP27, MM20, EP26, C40, MM22, EP14, C62, C57, MM23, POCT06, EP19, H54, POCT14, H44, EP10, MM12, POCT04, H47, H57, GP40, EP33, H48, EP34, EP31, C63, POCT16, MM24 NOTE 1: A calibration may be expressed by a statement, calibration function, calibration diagram, calibration curve, or calibration table. In some cases, it may consist of an additive or multiplicative correction of the indication with associated measurement uncertainty (JCGM 200:2012); NOTE 2: Calibration should not be confused with adjustment of a measuring system, often mistakenly called “self-calibration,” nor with verification of calibration (JCGM 200:2012); NOTE 3: Often, the first step alone in the above definition is perceived as being calibration (JCGM 200:2012); NOTE 4: Calibration is the procedure used, under predefined conditions, to establish a relationship of the sensor glucose measurement to the glucose reading of a predetermined standard; NOTE 5: The relationship of the sensor glucose measurement should be established to a biological medium; NOTE 6: Some of the factors that should be considered are the conditions under which the sensor can be effectively calibrated, number of measurements that are required under specific conditions for the device to start providing glucose values, and the frequency of subsequent calibrations needed to maintain accuracy over the lifetime of the sensor; NOTE 7: Calibration process is performed to meet accuracy claims; NOTE 8: Calibration permits either the assignment of values of the measurands to the measurement indications provided by the measuring instrument, or the determination of a correction with respect to the values provided by the measuring instrument (ISO 18113-1); NOTE 9: Calibration is sometimes confused with adjustment of a measuring system, often mistakenly called self calibration, or with calibration verification (ISO 18113-1); NOTE 10: The process of testing and adjusting an instrument, kit, or test system to establish a correlation between the measurement response and the concentration or amount of the substance measured by the test procedure (modified from 42 CFR §493.2); NOTE 11: Calibration can also be described as the set of operations that establishes the relationship between measured signal and concentration based on calibration materials of known concentration; NOTE 12: Calibration is the set of operations that establish, under specified conditions, the relationship between reagent system/instrument response and the corresponding concentration/activity values of an analyte; NOTE 13: Calibration establishes the relationship between equipment or instrument response and the corresponding predetermined concentration or activity values of an analyte; NOTE 14: According to the US Code of Federal Regulations, calibration is the process of testing and adjusting an instrument or test system to establish a correlation between the measurement response and the concentration or amount of the substance that is being measured by the test procedure; NOTE 15: According to published regulations, calibration is the process of testing and adjusting an instrument or test system to establish a correlation between the measurement response and the concentration or amount of the substance that is being measured by the test procedure (42 CFR §493.2).
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calibration provision of a measurement system with a contemporaneous value of the same analyte made by a different (reference) method, intended to bring the measurement system’s reported values into better agreement with those of the reference method
Project: POCT05
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calibration process of assessing (and adjusting if necessary) the critical outputs of an instrument to a calibrator of a known value before performing laboratory work Project: H26, H44, POCT13, POCT17, H62 NOTE 1: Process of testing and adjusting an instrument or test system to establish a correlation between the measurement response and the concentration or amount of the substance that is being measured by the test procedure (42 CFR § 493.2); NOTE 2: Comparison of a measurement instrument or system of unverified accuracy with a measurement instrument or system of known accuracy to detect any variation from the required performance specification.
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calibration comparison of a measurement instrument or system of unverified accuracy to a measurement instrument or system of known accuracy to detect any variation from the required performance specification Project: QMS07, QMS13, QMS23, QMS24, QMS01 Source: Quality Glossary
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calibration curve expression of the relation between indication and corresponding measured quantity value (JCGM 200:2012) Project: ISO IEC Guide 99, MM19, H48 NOTE: A calibration curve expresses a one-to-one relation that does not supply a measurement result as it bears no information about the measurement uncertainty (JCGM 200:2012).
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calibration curve the graphical relationship between the readings obtained in an analytical process (eg, absorbance, voltage) and the amount of analyte in a calibrator Project: NRSCL8 NOTE: The relationship is often a straight line rather than some other form of curve.
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calibration diagram graphical expression of the relation between indication and corresponding measurement result (JCGM 200:2012) Project: ISO IEC Guide 99 NOTE 1: A calibration diagram is the strip of the plane defined by the axis of the indication and the axis of measurement result, that represents the relation between an indication and a set of measured quantity values. A one-to-many relation is given, and the width of the strip for a given indication provides the instrumental measurementuncertainty (JCGM 200:2012); NOTE 2: Alternative expressions of the relation include a calibration curve and associated measurement uncertainty, a calibration table, or a set of functions (JCGM 200:2012); NOTE 3: This concept pertains to a calibration when the instrumental measurement uncertainty is large in comparison with the measurement uncertainties associated with the quantity values of measurement standards (JCGM 200:2012).
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calibration hierarchy sequence of calibrations from a reference to the final measuring system, where the outcome of each calibration depends on the outcome of the previous calibration (JCGM 200:2012) Project: ISO IEC Guide 99, EP32 NOTE 1: Measurement uncertainty necessarily increases along the sequence of calibrations (JCGM 200:2012); NOTE 2: The elements of a calibration hierarchy are one or more measurement standards and measuring systems operated according to measurement procedures (JCGM 200:2012); NOTE 3: For this definition, the “reference” can be a definition of a measurement unit through its practical realization, or a measurement procedure, or a measurement standard (JCGM 200:2012); NOTE 4: A comparison between two measurement standards may be viewed as a calibration if the comparison is used to check and, if necessary, correct the quantity value and measurement uncertainty attributed to one of the measurement standards (JCGM 200:2012); NOTE 5: Metrological traceability chain is synonymous with calibration hierarchy.
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calibration interval a period of time or series of measurements during which calibration can be expected to remain stable within specified and documented limit (U.S. CFR 493 February 28, 1992)
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calibration interval period of time following a calibration during which a product under specified conditions demonstrates apparent change in measurand content within the allowable drift limit and all stability-related criteria are met Project: EP25
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calibration line the graphic relationship (typically linear) between the clotting time in seconds and the international normalized ratio of certified plasmas Project: H54, H47
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calibration material a material or device of known or assigned quantitative characteristics (eg, concentration, activity, intensity, reactivity, responsiveness) used to adjust the output of a measurement procedure or to compare the response obtained with the response of a test specimen and/or sample Alternate Term: calibrator Project: NRSCL08, QMS24, H62 NOTE 1: The guideline document for the HCFA regulations in the United States (Appendix C, Survey procedures, PC122) defines a calibration material as “a solution which has a known amount of analyte weighed in or has a value determined by repetitive testing using a reference or definitive test method”; NOTE 2: The quantities of the analytes of interest in the calibration material are known within limits ascertained during its preparation and may be used to establish the relationship of an analytical method’s response to the characteristic measured for all methods or restricted to some; NOTE 3: Calibration materials with different amounts of analytes may be used to establish a calibration or response “curve” over a range of interest; NOTE 4: The term “standard,” commonly used in clinical laboratory protocols and having there a meaning as described here, has a specific and different meaning in the U.S. CFR 493, February 28, 1992; NOTE 5: The terms “primary” and “secondary standard” are used by WHO and ISO to refer to calibration materials; NOTE 6: The calibration material should be traceable to a national or international reference preparation or reference material when these are available; NOTE 7: Quantitative fluorescence calibrators can be spectrally matched or differ in spectral properties. Although the spectrally matched calibrator is superior, especially for probes with pH sensitivities, the equivalent reference fluorophores method for calibrators provides an alternative for fluorochromes lacking National Institute of Standards and Technology traceable material or standard reference material; NOTE 8: See equivalent reference fluorophores and standard reference material.
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calibration material a material (eg, solution) or device of known quantitative/qualitative characteristics (eg, concentration, activity, intensity, reactivity) used to calibrate, graduate, or adjust a measurement procedure or to compare the response obtained with the response of a test specimen/sample Project: I/LA20, I/LA34 NOTE 1: The quantities of the analytes of interest in the calibration material are known within limits ascertained during its preparation and may be used to establish the relationship of an analytical method’s response to the characteristic measured for all methods or restricted to some; NOTE 2: The calibration material must be traceable to a national or international reference preparation or reference material when these are available; NOTE 3: Calibration materials with different amounts of analytes may be used to establish a calibration or response “curve” over a range of interest; NOTE 4: The terms “primary” and “secondary standard” are used by the World Health Organization and the International Organization for Standardization to refer to calibration materials; NOTE 5: See calibrator.
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calibration procedures refer to the methods used to translate a device response measurement into a concentration, activity, or other outcome measurement. Calibration usually involves measurement of the device response in relation to special samples of known values called calibrators Project: MM06
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calibration standard solution, prepared from reference material, that is used to calibrate the instrument response to measurand concentration Project: C40 NOTE: There is no International Organization for Standardization (ISO) term for "calibration standard." In ISO terminology, it would be called a “reference material” used for calibration. See reference material.
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calibration transfer protocol detailed description for assigning a value of a quantity to a reference material using a specified sequence of measurement procedures calibrated by higher-order reference materials for the same type of quantity Alternate Term: transfer protocol Project: ISO 17511
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calibration verification the assaying of calibration materials in the same manner as patient samples to confirm that the calibration of the instrument, kit, or test system has remained stable throughout the measurement range for patient test results Project: QMS13, QMS23, MM06, POCT04, POCT09, H26, QMS01 Source: Quality Glossary NOTE: US CFR 493.2
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calibrator measurement standard used in calibration (JCGM 200:2012) Project: ISO IEC Guide 99, C34, H26, MM06, NBS05, C40, H48, POCT04, QMS24, I/LA20, H62, NBS10 NOTE 1: The term “calibrator” is only used in certain fields (JCGM 200:2012); NOTE 2: A material or device of known or assigned quantitative characteristics (eg, concentration, activity, intensity, reactivity, responsiveness) used to adjust the output of a measurement procedure or to compare the response obtained with the response of a test specimen and/or sample; NOTE 3: The quantities of the analytes of interest in the calibration material are known within limits established during its preparation; NOTE 4: Calibration materials with different amounts of analytes may be used to establish a calibration or response “curve” over a range of interest; NOTE 5: An instance in which the testing procedure is performed by a health care provider for an individual or individual; NOTE 6: Calibrators with different quantities or analytes may be used to establish a quantity/response “curve” over a range of interest; NOTE 7: A calibration material may be used for all measurement procedures or restricted to some within limits established during its preparation; NOTE 8: Calibrators can be used internal (within the same tube) or external (in another tube) to the specimen. In such cases, within MM06, they are referred to as internal calibrators or external calibrators.
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calibrator reference material whose value is used for the independent variable in a calibration function (ISO 17511) Alternate Term: calibration material Project: ISO 17511, I/LA23, QMS23
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calibrator a reference material (eg, solution, suspension) or device of known quantitative/qualitative characteristics (eg, concentration, activity, intensity, reactivity) used to calibrate, graduate, or adjust a measurement procedure or to compare the response obtained with the response of a test specimen/sample Project: H26 NOTE: The quantities of the measurands of interest in the calibrator are known within limits ascertained during its preparation and may be used to establish the relationship of a measurement procedure’s response to the characteristic measured for all methods or restricted to some. The calibrator must be traceable (see CLSI document H15) to a national or international reference preparation or reference material when these are available. Calibrators with different quantities of measurands may be used to establish a quantity/response curve over a range of interest, although most hematology analyzers use a single-point calibration.
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calibrator measurement standard used in the calibration of an IVD instrument or system (adapted from JCGM 200:2012) Project: ISO 18113-1
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calibrator substance, material, or article intended to be used in the calibration of an in vitro diagnostic medical device (modified from EN 375) Project: ISO 18113-1, ISO 18113-2, ISO 18113-3
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calibrator See calibration material Project: I/LA34
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calibrator substance, material, or article intended by its manufacturer to be used to establish the measurement relationships of an in vitro diagnostic medical device Project: EP31
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calorie the amount of heat it takes to raise the temperature of 1000 g or 1 kg of water one degree Centigrade Project: GP28 NOTE: A Calorie is actually a kilocalorie or 1000 calories.
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calorie the amount of heat it takes to raise the temperature of 1 g of water 1 degree centigrade Project: GP28 NOTE: The cal/min is the unit of heat per minute.
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candidate measurement procedure measurement procedure for which the performance characteristics are being evaluated for suitability for clinical use Project: EP21, EP27
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candidate reagent lot any reagent lot about to be used for the first time in a specific medical laboratory Project: EP26
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candidate specimen the specimen that is being assessed or evaluated for the purpose of establishing suitability Project: EP35 NOTE: In CLSI EP35, the term “candidate specimen” is used for assessing equivalence between two specimen types.
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capability ability to deliver an intended outcome of an exercise with any combination of properly planned, organized, equipped, trained, and exercised personnel though the execution of plan documents Project: GP36
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capacity the maximum amount or number that can be received or contained (RHUD1.7CD)
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capacity factor fraction of a sample compound distributed into stationary phase divided by the fraction in mobile phase Project: C62 NOTE: It is also called retention factor and symbolized as kʹ.
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capillary one of the minute blood vessels between the terminations of the arteries and the beginnings of the veins (RHUD1.7CD) Project: GP48
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capillary action the net chemical and physical effects that cause a liquid to rise (be drawn up) into a narrow-bore tube (capillary tube) in the absence of an atmospheric pressure differential Alternate Term: capillarity Project: H14, POL1/2
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capillary blood blood obtained by skin puncture or incision that contains a mixture of undetermined proportions of blood from arterioles, venules, and interstitial and intracellular fluids Project: GP42, GP39, GP34
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capillary blood sample blood collected after puncturing minute vessels that connect the arterioles and venules (ISO 17593) Project: ISO 17593 NOTE: Often obtained by pricking a fingertip; capillary blood is usually collected without additives, such as anticoagulants or preservatives. Therefore, it is inherently unstable (ISO 17593).
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capillary electrophoresis electrophoretic technique in which DNA fragments are separated by size in a thin capillary filled with a viscous matrix Project: MM05 NOTE: Typically, capillary electrophoresis is performed at a high voltage, and the separation is faster than other gel electrophoretic techniques. Separation is based both on molecular size and in some cases on ion current flows.
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capillary puncture the collection of blood using a minimally invasive lancet or puncture device Project: POCT14 NOTE: The most commonly used site to collect blood by capillary puncture for point-of-care coagulation testing is the finger.
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capillary puncture device a single-use device that punctures or cuts the skin with a sharp pointed or bladed instrument that automatically retracts into a protective housing Project: GP42
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capillary tube a hollow cylindroid of sufficiently narrow internal diameter such that it brings about capillary action when its tip is placed in a fluid specimen Project: GP42 NOTE: A capillary tube is also known as a capillary straw.
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capsule a mucopolysaccharide material surrounding a cell wall Project: M54
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capture microsphere calibrator as used in this document, a microsphere that has been surface-labeled with a reagent, usually an antibody, that binds fluorochrome-labeled ligands Project: I/LA24
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Carba NP test colorimetric microtube assay for detecting carbapenemase production Project: M02, M07, VET01 Source: Microbiology Glossary
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carbon dioxide (CO2) a colorless, odorless, incombustible gas that is a primary product of aerobic metabolism and is found dissolved and chemically bound in blood and other tissues Alternate Term: CO2 Project: NRSCL8
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carboxyfluorescein succinimidyl ester a cell-labeling fluorescent dye typically excited by a “blue” (488 nm) laser which, upon entering cells, covalently links to intracellular proteins Project: I/LA26 NOTE 1: The linkage is very stable and the dye, once linked to intracellular molecules, does not leak out of cells or transfer to other cells; NOTE 2: Due to the progressive halving of the amount of dye with each successive cell division, and the ability to detect and measure this reduced fluorescence by flow cytometry, carboxyfluorescein succinimidyl ester measurements have been used as a marker of proliferation; NOTE 3: Carboxyfluorescein succinimidyl ester is excited at approximately 494 nm with an emission maximum at 521 nm.
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carboxyhemoglobin (COHb) a dyshemoglobin with heme groups that are covalently bonded to carbon monoxide Project: C25, C41
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carcinogen any substance capable of causing malignant tumors in humans or animals Project: GP05 NOTE: See the Agency for Toxic Substance and Disease Registry annual report for current information on carcinogens.
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carcinogen a substance, organism, or agent capable of causing cancer Project: QMS28 NOTE: A listing in the US Department of Health and Human Service’s Report on Carcinogens (ROC) identifies a substance or exposure circumstance as known or reasonably anticipated to be a human carcinogen and thus indicates a potential hazard
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cardiopulmonary bypass a procedure during which a machine takes over the function of the heart and lungs in order to sustain organ perfusion with oxygenated blood during cardiac surgery Project: POCT14
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caregiver a person that provides care to people who need some degree of ongoing assistance with everyday tasks on a regular or daily basis Project: PRE05
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carnitine a seven-carbon molecule with three important functional groups: a quaternary ammonium functionality, a carboxylic group, and a secondary alcohol Project: NBS04, NBS09 NOTE: See acylcarnitine.
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carnitine and acylcarnitines Carnitine is a five-carbon molecule with three important functional groups: a quaternary ammonium functionality, a carboxylic group, and a secondary alcohol. Carnitine esters, known as acylcarnitines, are derived by conjugation of fatty acids and carnitine through the alcohol group. The fatty acid attached to carnitine reflects the composition of fatty acids within the mitochondria. The fatty acids are typically between two and 20 carbons, may be saturated or unsaturated, and may contain a hydroxyl or carboxylic acid group. The elemental composition of the fatty acid is important in determining the mass of the acylcarnitine and, hence, its identification. Acylcarnitines function as biomarkers for a number of inherited metabolic disorders (fatty acid oxidation disorders and organic acidemias) NOTE: Throughout NBS04, the acylcarnitine species are referred to by their acyl chain carbon lengths (eg, octanoylcarnitine is referred to as C8). See the figures in Appendix I for the chemical structures of carnitine and acylcarnitines.
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carrier See specimen carrier Project: AUTO02, AUTO12
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carrier a molecule to which a microbial polysaccharide is chemically linked for the purpose of eliciting a T-cell-dependent immune response and thus modifying the humoral immune response to the polysaccharide
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carrier (operator) individual or organization engaged in the commercial transportation of goods Project: M29
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carrier frequency the proportion of individuals in a population who have a single copy of a particular gene at a specific locus Project: MM17 NOTE: For disease-related genes, carrier frequency describes the proportion of individuals in a population who carry a recessive variant that is pathogenic for a specific condition.
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carrier protein a protein to which a specific ligand or hapten is conjugated Project: DI01
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carrier screening the identification of asymptomatic individuals of both sexes who are heterozygous for a common recessive disorder or females heterozygous for an X-linked recessive disorder and at risk to have an affected child
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carryover unintended contamination of a sample undergoing IVD examination with material from a previous sample (ISO/DIS 18113) Project: ISO 18113-1, ISO 18113-2, ISO 18113-3
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carryover the discrete amount of reagent or analyte carried by the measuring system from one sample into another sample and thereby erroneously affecting test results Project: H44, H56, I/LA33, MM01
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carryover process by which material is introduced into a reaction mixture to which it does not belong (ISO/DIS 18113-1) Project: ISO DIS 18113-1 EXAMPLE: Part of a sample, reagent, diluent or wash solution that is transferred from one container, or from one reaction mixture, to another one (ISO/DIS 18113-1); NOTE 1: Carryover can be either unidirectional or bidirectional (ISO/DIS 18113-1); NOTE 2: Adapted from: IUPAC, Compendium of Analytical Nomenclature, 3rd edition (1998); Inczedy J, Lengyel T, Ure AM, eds.
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carryover unintended transfer of a fraction or element of a sample or reagent from one testing event to a subsequent testing event(s), occurring as a systematic event Project: EP10
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carryover unintended transfer of material in a test method from a patient sample or reagent into other samples, reagents, materials, or parts of the instrument, potentially causing a carryover effect (ie, a quantifiable difference in other test results) Project: EP47 NOTE: Carryover can also manifest as cross-contamination; for example, reagent clinging to a reagent probe contaminates the next reagent or insufficient washing of a reaction cell affects subsequent sample measurements.
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carryover effect a quantifiable change in the measurement result (or raw data, such as signal) caused by sample or reagent carryover Project: EP10
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cartridge one type of unit-use device containing the components necessary to perform a test, including sensors, reagents, and calibration materials. A cartridge typically requires a meter to read signals and report results Project: POCT07, POCT04
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cascade reporting strategy of reporting antimicrobial susceptibility test results on an individual patient's isolate in which secondary (eg, broader spectrum, sometimes more costly) agents may only be reported if an organism is resistant to primary agents within a particular drug class Project: M39
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case definition a set of criteria (not necessarily diagnostic criteria) that must be fulfilled in order to identify a person as representing a case of a particular disease or condition Project: POCT16 NOTE: Case definitions can be based on clinical, laboratory, epidemiological, or combined clinical and laboratory criteria. When a set of criteria is standardized for purposes of identifying a particular disease, it is referred to as a “standard case definition.” A surveillance case definition is standardized and used to accurately detect all cases of the targeted disease or condition in a given population, while excluding the detection of other similar conditions.
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case-control study type of observational study design in which determination of outcome precedes determination of exposure Project: GP45 NOTE 1: In this study design, the relationship of an attribute of subjects (or their environment) to the occurrence of a disease or other outcome of interest is examined by comparing a group of persons having this outcome (cases) with a suitable control (comparison, reference) group. The two groups are compared with respect to how frequently the attribute is present, or if quantitative, the levels of the attribute in each of the two groups. In other words, the past history of exposure to a suspected risk factor is compared between “cases” and “controls.” The controls are persons who resemble the cases in such respects as age and sex, but do not have the disease or outcome of interest; NOTE 2: This study design starts after the occurrence of the outcome and looks back to the postulated causal factors. Cases and controls may be accumulated either retrospectively (ie, from among subjects whose outcome and exposure status are already known) or prospectively (ie, as each new case is determined, it is entered into the study).
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case-finding the performance of tests on an opportunistic basis when an individual presents to the health care system with a complaint unrelated to the tests performed Project: ISO 15196, ISO TR 15196 EXAMPLE: Investigations ordered as part of routine "healthy checkups" and may employ screening tests.
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casework premanufactured cabinet/countertop systems Project: QMS04
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casual glucose See nonfasting glucose Alternate Term: nonfasting glucose; randomly timed glucose Project: POCT13
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casualty victim of an accident or disaster, usually referring to both deceased and living victims Project: GP36 NOTE: To be distinguished from “fatality.”
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catalyst a substance that increases the kinetics of a chemical reaction without being consumed in the reaction Project: GP40
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catalytic activity (ZE) property of a component corresponding to the catalyzed substance rate of conversion of a specified chemical reaction, in a specified measurement system (ISO 18153) Project: ISO 18153 NOTE 1: Adapted from IUPAC/IFCC 1995:9.101.3 (ISO 18153); NOTE 2: In this standard, the "component" is an enzyme (ISO 18153); NOTE 3: The quantity "catalytic activity" relates to an amount of active enzyme, not its concentration; see catalytic-activity concentration (ISO 18153); NOTE 4: The coherent derived SI unit is "mole per second" (mol s-1), also called "katal" (kat) (modified from ISO 18153); NOTE 5: The measurement procedure is an essential element of the definition of the measurand (ISO 18153); NOTE 6: In many instances, instead of the conversion rate of the substrate ascribed in the short name of the enzyme analyte, eg, "creatine" in "creatine kinase," the conversion rate of an indicator substance as substrate of a combined reaction, eg, NADH, is measured. Then the measurand should be defined as "catalytic activity of the enzyme as measured by the conversion rate of an indicator substance in a specified system according to a given measurement procedure," eg, "catalytic activity of creatine kinase as measured by the rate of conversion of NADP in the IFCC reference procedure in human serum" (ISO 18153).
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catalytic activity concentration (bE) catalytic activity of a component divided by volume of the original system (ISO 18153) Alternate Term: catalytic concentration Project: ISO 18153 NOTE 1: Adapted from IUPAC/IFCC 1995:9.104.2 (ISO 18153); NOTE 2: The coherent derived SI unit is "mole per second cubic metre" (mol s-1 m-3 = kat m-3). In laboratory medicine, the unit of volume may be chosen to be "litre" (l) (modified from ISO 18153); NOTE 3: In ISO 18153, the "component" is an enzyme and the "original system" can be, e.g., the plasma of a blood sample (ISO 18153).
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catalytic concentration See catalytic activity concentration
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category 1 laboratory a laboratory that accepts specimens for anaerobic culture but only detects the presence of anaerobes Project: M56 NOTE: Anaerobes are referred to another laboratory for identification and antimicrobial susceptibility testing.
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category 2 laboratory a laboratory that screens for the major anaerobic groups Project: M56 NOTE: Definitive identification and antimicrobial susceptibility testing are performed in a reference laboratory.
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category 3 laboratory a laboratory that can identify anaerobes to genus and species level using phenotypic and enzymatic tests Project: M56 NOTE: It may perform some antimicrobial susceptibility testing.
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category 4 laboratory a laboratory that provides final identifications using 16s ribosomal RNA gene sequencing or matrix-assisted laser desorption/ionization time-of-flight technology Project: M56 NOTE: It may perform quantitative antimicrobial susceptibility testing.
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Category A, infectious substance See infectious substance, Category A Alternate Term: infectious substance, Category A Project: M29
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category agreement (CA) agreement of SIR results between a breakpoint test or an MIC test and the reference method (ISO 20776-1); Another representation of the concept: NCA × 100/N,whereNCA is the number of bacterial isolates with the same SIR category as the reference method category result; N is the total number of bacterial isolates tested (ISO 20776-2) Project: ISO 20776-2 NOTE: The overall CA is expressed as a percentage (ISO 20776-2).
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category agreement agreement of susceptible, intermediate, susceptible-dose dependent, and resistant results between a breakpoint test or a minimal inhibitory concentration test and the reference method (modified from ISO 20776-2) Project: M52 NOTE: Another representation of the concept: NCA • 100/N where: NCA is the number of microbial isolates with the same susceptible, intermediate, susceptible-dose dependent, and resistant category as the reference or comparator method category result; N is the total number of microbial isolates tested (modified from ISO 20776-2).
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Category B, biological substance See biological substance, Category B Alternate Term: biological substance, Category B. Project: M29
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catheter a hollow tube of rubber or plastic, passed through the urethra for the purpose of collecting urine directly from the urinary bladder Project: GP16, PRE05
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catheter specimen a urine specimen collected from a catheter placed into the bladder through the urethra
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catheter tubing (urinary) a hollow long structure that permits the passage of urine from the urinary catheter to the drainage bag Project: PRE05 NOTE: The tubing is usually made of flexible transparent plastic.
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cathode negatively charged conductor that is the source of electrons in an electrical device Project: GP28
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cation resin an ion-exchange resin with immobilized negatively charged exchange sites, which can bind positively charged ionized species Project: GP40
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CD4 and CD8 T-cells the two major classes of mature T-cells, which are marked by the usually mutually exclusive expression of the molecules CD4 and CD8 Project: I/LA26 NOTE 1: CD4 T-cells typically recognize peptides bound to Class II major histocompatibility protein complexes and provide help to B-cells, macrophages, dendritic cells, and CD8 T-cells; NOTE 2: CD8 T-cells typically recognize peptides bound to Class I major histocompatibility protein complexes and are best known for their cytotoxic function.
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CE marking symbolizes the conformity of the product with the applicable European Community requirements imposed on the manufacturer. The CE marking affixed to products is a declaration by the person responsible that the product conforms to all applicable European Community provisions, and the appropriate conformity assessment procedures have been completed (see Guide to the Implementation of Directives Based on New Approach and Global Approach) Project: H59, MM07, MM03
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CEF a pool of 23 8-11-mer peptides representing conserved epitopes from cytomegalovirus, Epstein-Barr virus, and influenza virus (CEF peptide pool), restricted by common major histocompatibility complex Class I alleles Project: I/LA26
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cell a single dark or light element within a matrix-based two-dimensional symbol Project: AUTO14
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cell block a paraffin section slide made from the centrifuged remains of a cytology specimen in fluid Project: MM23 NOTE: Cell blocks are made only when sufficient material remains in the container after preparation of cytology smears or thin-layer preparations.
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cell culture technique for growing cells in a laboratory setting
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cell culture propagation serial transfer of suspended cell culture cells (eg, derived from a trypsinized monolayer) to a fresh culture vessel containing growth medium Project: M41
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cell smear tissue or cellular sample that is smeared across a glass microscope slide for subsequent staining and microscopic examination Project: MM23 NOTE: Cell cytology samples also can be prepared by centrifugation.
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cell wall stain stain that highlights the cell wall (eg, calcofluor white, Gomori methenamine silver) Project: M54
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cell-free DNA DNA located in body fluids such as plasma that is the result of shedding of primarily nuclear DNA from lysed cells during the normal process of cellular death (apoptosis) and/or cellular necrosis Project: MM13 NOTE 1: Typical cell-free DNA fragment size is less than 180 base pairs on average, with size characteristics consistent with enzymatic nucleosome-associated cleavage; NOTE 2: Cell-free DNA in oncology applications may also be referred to as circulating cell-free tumor DNA; NOTE 3: Cell-free fetal DNA is genetic material that is released by the placenta and circulates in a woman’s blood during pregnancy.
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cellulose acetate electrophoresis electrophoresis in which microporous cellulose acetate (strips or plates) is the support medium for the solutes and solvents
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cellulose acetate membrane a reverse osmosis membrane constructed of cellulose diacetate/triacetate Project: GP40
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censored data the situation in which measurement results are simply reported as greater than or less than an imposed threshold rather than expressed in quantitative units Project: EP17 NOTE: For example, a result is known to be less than a stated limit but the actual result value is not available.
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central congenital hypothyroidism congenital hypothyroidism caused by deficient secretion of thyroid-stimulating hormone by the pituitary gland, which may be due to a pituitary (ie, secondary congenital hypothyroidism) or hypothalamic (ie, tertiary congenital hypothyroidism) abnormality Project: NBS10 Source: Newborn Screening Glossary NOTE: Central congenital hypothyroidism does not include secretion of a nonfunctioning thyroid-stimulating hormone molecule, which clinically resembles primary congenital hypothyroidism.
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central laboratory for CLSI document POCT07, a term chosen to conceptualize what is meant by the central, core, or main clinical laboratory setting to differentiate it from the point-of-care setting Project: POCT07 NOTE: See clinical laboratory.
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centrifugation separation of solids from liquids using rotational forces Project: QMS04
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centrifugation phase the time period when the specimen is inside the centrifuge
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centrifugation tube a glass or plastic tube in which urine is centrifuged for the purpose of preparing sediment for microscopic evaluation Project: GP16 NOTE: Supernatant may also be tested when formed elements interfere with some chemical assays.
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cerebrospinal fluid the fluid in the ventricles of the brain, between the arachnoid mater and the pia mater, and surrounding the spinal cord Project: C49
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cerebrospinal fluid fluid within the ventricles of the brain and the subarachnoid space Project: H56
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certificate (digital certificate) a certificate document in the form of a digital data object (a data object used by a computer) to which is appended a computed digital signature value that depends on the data object (RFC 2828) Project: AUTO09
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Certificate of Analysis document provided by the manufacturer stating that the released product meets all Quality System Regulation requirements and quality control specifications Project: M50 NOTE: Certificates of Analysis apply to individual lots of the product (ie, lot-specific).
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certificate of analysis document provided by the producer of a reference material stating the intended use, measured value, measurement uncertainty, commutability with clinical samples when applicable, and a statement that the released product meets all quality system requirements and quality control specifications Project: EP30
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Certificate of Compliance document provided by the manufacturer stating that the product meets all Quality System Regulation requirements and quality control specifications Alternate Term: COC Project: M50 NOTE: Certificates of Compliance apply to all lots of the product (ie, product-specific).
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certificate revocation list a data structure that enumerates digital certificates that have been invalidated by their issuer prior to when they were scheduled to expire (RFC 2828) Project: AUTO09
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certification process by which a qualified third party provides attestation that a system, process, product, or person conforms to specified requirements Project: QMS04, QMS21, QMS25 Source: Quality Glossary
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certification a written statement by an authorized body that a product, production plant, or laboratory meets certain specifications or requirements (WHO-BS 95/1793) Project: MM19 NOTE: Procedure by which a third party gives written assurance that a service conforms to specified requirements.
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certification process by which an external organization gives written assurance that a service or person conforms to specified requirements Project: GP23, GP48, QMS17
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certification authority an entity that issues digital certificates (especially X.509 certificates) and vouches for the binding between the data items in a certificate (RFC 2828) Project: AUTO09
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certified plasmas normal or abnormal plasma samples assigned a prothrombin time/international normalized ratio value by a manufacturer or reference center, using a manual method based on a World Health Organization accepted protocol determined against an appropriate thromboplastin international reference preparation (or manufacturer or standard reference reagent) that has been calibrated against the appropriate World Health Organization standard in a multicenter study (ie, a minimum of three laboratories for a primary standard and two laboratories for a secondary standard) Project: H54, H47
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certified reference material reference material, accompanied by documentation issued by an authoritative organization and providing one or more specified property values with associated uncertainties and traceabilities, using valid procedures (modified from JCGM 200:2012) Project: EP12, JCGM 200:2012, MM06, I/LA28, EP29, MM20, EP30, C40, C62, H48, MM17, EP32 EXAMPLE: Human serum with assigned quantity value for the concentration of cholesterol and associated measurement uncertainty stated in an accompanying certificate, used as a calibrator or measurement trueness control material (JCGM 200:2012); NOTE 1: “Documentation” is given in the form of a “certificate” (see ISO Guide 31:2000) (JCGM 200:2012); NOTE 2: Procedures for the production and certification of certified reference materials are given, eg, in ISO Guide 34 and ISO Guide 35 (JCGM 200:2012); NOTE 3: In this definition, “uncertainty” covers both “measurement uncertainty” and “uncertainty associated with the value of a nominal property,” such as for identity and sequence. “Traceability” covers both “metrological traceability of a quantity value” and “traceability of a nominal property value” (JCGM 200:2012); NOTE 4: Specified quantity values of certified reference materials require metrological traceability with associated measurement uncertainty (Accred Qual Assur. 2006;10:576-578); NOTE 5: ISO/REMCO has an analogous definition (Accred Qual Assur. 2006;10:576-578) but uses the modifiers “metrological” and “metrologically” to refer to both quantity and nominal property (JCGM 200:2012); NOTE 6: A material that is used as a standard or reference and whose assigned value is traceable to a reference measurement system. An accompanying certificate states the measurand value and the measurement uncertainty.
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certified reference material reference material, accompanied by a certificate, one or more of whose property values are certified by a procedure which establishes traceability to an accurate realization of the unit in which the property values are expressed, and for which each certified value is accompanied by an uncertainty at a stated level of confidence (ISO Guide 30) Project: ISO 15195 NOTE 1: The definition of a “reference material certificate” is given in Section 4.2 of ISO Guide 30:1992; NOTE 2: Certified reference materials are generally prepared in batches for which the property values are determined within stated uncertainty limits by measurements on samples representative of the whole batch; NOTE 3: The certified properties of certified reference materials are sometimes conveniently and reliably realized when the material is incorporated into a specially fabricated device, eg, a substance of known triple-point into a triple-point cell, a glass of known optical density into a transmission filter, spheres of uniform particle size mounted on a microscope slide. Such devices may also be considered as certified reference materials; NOTE 4: All certified reference materials lie within the definition of “measurement standards” or “etalons” given in the “International Vocabulary of Basic and General Terms in Metrology”; NOTE 5: Some reference materials and certified reference materials have properties which, because they cannot be correlated with an established chemical structure or for other reasons, cannot be determined by exactly defined physical and chemical measurement methods. Such materials include certain biological materials such as vaccines to which an International unit has been assigned by the World Health Organization; NOTE 6: A material that is used as a standard or reference and whose assigned value is traceable to a reference measurement system. An accompanying certificate states the measurand value and the measurement uncertainty.
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certified reference material reference material, accompanied by a certificate, one or more of whose property values are certified by a procedure which establishes metrological traceability to an accurate realization of the unit in which the property values are expressed, and for which each certified value is accompanied by an uncertainty at a stated level of confidence (ISO 17511) Project: ISO 17511
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certified reference material a reference material that has one or more values certified by a technically valid procedure and is accompanied by, or is traceable to, a certificate or other document that is issued by a certifying body Project: H15 NOTE: The term “Standard Reference Material” is the name of a certified reference material, which is the trademark name of a certified reference material that has been certified and is distributed by the National Institute of Standards and Technology, a US government agency formerly known as the National Bureau of Standards.
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certified reference material reference material, accompanied by documentation issued by an authoritative body and referring to valid procedures used to obtain a specified property value with uncertainty and traceability (ISO 15194) Project: ISO 15194 EXAMPLE: Human serum containing cholesterol with assigned quantity value and associated measurement uncertainty stated in an accompanying certificate, used as calibrator or trueness control material (ISO 15194); NOTE 1: In this definition, uncertainty covers both “measurement uncertainty” and “uncertainty of nominal value,” such as for identity and sequence, expressed as probabilities. Traceability covers both “metrological traceability” of a quantity value and “traceability of nominal value” (ISO 15194); NOTE 2: “Certified reference material” is a specific concept under “reference material” (ISO 15194).
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certified reference material reference material characterized by a metrologically valid procedure for one or more specified properties, accompanied by a reference material certificate that provides the value of the specified property, its associated uncertainty, and a statement of metrological traceability (ISO Guide 30) Project: C64 NOTE 1: The concept of value includes qualitative attributes such as identity or sequence. Uncertainties for such attributes may be expressed as probabilities (modified from ISO Guide 30); NOTE 2: Metrologically valid procedures for the production and certification of reference materials are given in, among others, ISO Guides 34 and 35 (ISO Guide 30); NOTE 3: ISO Guide 31 gives guidance on the contents of reference material certificates (ISO Guide 30).
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certified value value, assigned to a property of a reference material that is accompanied by an uncertainty statement and a statement of metrological traceability, identified as such in the reference material certificate (ISO Guide 30)
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cestode tapeworm Project: M28
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CFTR-related metabolic syndrome an asymptomatic, hypertrypsinogenemic infant with either a sweat chloride concentration of 30–59 mmol/L on at least two occasions and completed DNA analysis of the cystic fibrosis transmembrane conductance regulator (CFTR) gene with fewer than two cystic fibrosis–causing CFTR variants, or a sweat chloride concentration < 30 mmol/L and two CFTR variants, in trans, of which no more than one is known to be a pathogenic (cystic fibrosis–causing) variant Alternate Term: cystic fibrosis screen-positive, inconclusive diagnosis Project: NBS05
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CH50 unit in a complement fixation assay, the dilution of a serum that will lyse 50% of sensitized sheep red cells; used as a measure of specific antigen, antibody, or immune complex concentration Project: DL01
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CH50 unit in a complement fixation assay, the dilution of a serum that will lyse 50% of sensitized sheep red blood cells; used as a measure of specific antigen, antibody, or immune complex concentration Project: DI01
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chain of custody a forensic document that unequivocally identifies the donor of a specimen and tracks its handling from the time of collection to the completion of testing and disposal Project: C52, C63 NOTE: The chain of custody must not be broken and must account for the history of the specimen with no gaps. The chain of custody documentation must be retained in the laboratory for a specified period of time after completion of testing and the reporting of results.
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challenge 1) for quantitative tests, an assessment of the amount of substance or analyte/measurand present or measured in a sample; 2) for qualitative tests, the determination of the presence or the absence of an analyte/measurand, organism, or substance in a sample (modified from 42 CFR §493.2) Project: MM14, QMS24
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challenge for quantitative tests, an assessment of the amount of substance or analyte present or measured in a sample
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chance random error Project: GP45
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chancre a sore or ulcer located at the initial point of entry of a pathogen Project: M54
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change control a systematic, documented approach to evaluating, testing, approving, and implementing modifications to products, process, or systems to ensure that adverse affects are minimized and that resources are used efficiently Source: Quality Glossary
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change management systematic approach for defining, planning, coordinating, testing, tracking, and communicating a new or revised process and for preparing personnel for the transition to the future state Source: Quality Glossary
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change order written order to the contractor to change something that was previously shown in the approved drawings or specifications Project: QMS04
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channel smallest division on the intensity scale of a flow cytometer Project: H62 NOTE 1: The smallest unit of measurement for fluorescence intensity is referred to as the channel number. In older analog instruments, data were acquired in 256 or 1024 channels. More recently, cytometers divide the intensity of light signals into 1024 or more channels; NOTE 2: Signals with high channel numbers are brighter than signals with low channel numbers. However, the quantitative relationship between signals defined by one channel number and those defined by another depends on the amplifier and photodetector voltage characteristics of a given protocol; NOTE 3: Assignment of intensity to channel can be linear or logarithmic; NOTE 4: Sometimes used as a shortened form of “spectral channel,” which refers to the portion of the light spectrum captured by a detector based on the cytometer’s optical pathway (eg, “PE [phycoerythrin] channel”).
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chaotrope a chemical denaturing agent that solubilizes protein samples and lowers the melting temperature of double-stranded nucleic acids Project: MM03
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character 1) the smallest abstract element of a writing system or script; 2) a code element; 3) a member of a set of elements on which agreement has been reached and that is used for the organization, control, or representation of information; 4) a letter, digit, or other symbol that is used as part of the organization, control, or representation of data; 5) in data transmission, one of a set of elementary symbols that normally include both alpha and numeric codes plus punctuation marks and any other symbol that may be read, stored, or written and is used for organization, control, or representation of data; 6) in computers, a letter, digit, or other symbol used to represent information (IEEE 610.1, 610.5, 610.12) Project: AUTO01, AUTO07, AUTO02, AUTO03, AUTO12, AUTO14 NOTE 1: A character refers to an abstract idea rather than to a specific shape; NOTE 2: Characters may be letters, digits, punctuation marks, or other symbols, often represented in the form of spatial arrangement of adjacent or connected strokes or in the form of other physical conditions in the data media; NOTE 3: A character is often in the form of a spatial arrangement of adjacent or connected strokes (ASTM F149).
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characterization (of a reference material) process of determining the property values of a reference material, as part of the certification process Project: EP30 NOTE 1: The characterization process provides the values for the properties to be quantified; NOTE 2: In batch certifications, the characterization refers to the property values of the batch.
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Charcot Leyden crystals slender crystals that are formed from the breakdown products of eosinophils; shaped like double, elongated pyramids with pointed ends; can be found in feces, sputum, and tissues; indicates an immune response that may or may not be related to a parasitic infection Project: M28
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charge state the total charge on an ion divided by the elementary charge (e) Project: C64
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charges the price of a service or amount billed an individual or third party, which may or may not be equal or even proportional to service costs Project: GP45
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chartable/unchartable comments comments related in any way to a sample, patient, or set of results that are meaningful for the patient record (chartable), or meaningful only for laboratory staff (nonchartable) Project: AUTO15
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chartable/unchartable flags alerts (or flags) from an analyzer that are meaningful for the patient record (chartable) or meaningful only for laboratory staff (nonchartable) Project: AUTO15
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charter (n) document or authorization from the organization’s leadership that outlines and communicates the principles, scope, rights, and privileges for establishing a project, committee, function, etc
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charter (v) the granting of authority or rights, stating that the grantor formally recognizes the prerogative of the recipient to exercise the rights specified Project: QMS14 Source: Quality Glossary
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check character a value calculated from the encoded content in a linear bar code that is printed in a designated location in a bar code Project: AUTO14 NOTE 1: This check character is typically not part of the human-readable text on the label; NOTE 2: The formula for the calculation is specific to the bar code symbology being used; NOTE 3: When a bar code is decoded by the bar code reader, the bar code reader performs the same symbology-specific calculation on the decoded content of the bar code and then compares the result of the calculation against the decoded check character. If the calculated and decoded values do not match, then a non-read error is generated. If the calculated and decoded values match, then the bar code reader accepts the encoded content as valid intended content and sends it to the attached computer application. The uncommon instance in which the calculated and decoded check characters match but the content of the bar code is incorrectly decoded is known as a substitution (misread) error
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check sum character a character defined by a specific mathematical algorithm to check the validity of the serial number that has been entered, either electronically or manually, into the newborn screening data system. Project: NBS01
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checklist tool for organizing and ensuring that all important steps or actions in a process are considered or acted upon Project: QMS15 Source: Quality Glossary
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checksum see check character Project: AUTO14
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chemical ionization an ionization process that leads to new ionized species arising from the interaction between molecules and gas phase ions, formed specifically for the purpose (ie, as “reagent ions”) Project: C50 NOTE: Chemical ionization spectra are simpler than electron ionization spectra and are often dominated by an intense protonated or adducted molecular ion (M+H) + with few or no fragment ions.
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chemical ionization the formation of new ionized species when gaseous molecules interact with ions Project: C43 NOTE: The process may involve transfer of an electron, a proton, or other charged species between the reactants. When positive ion results from chemical ionization, the term may be used without qualification; when a negative ion results, the term “negative ion chemical ionization” can be substituted. Specifics relating to ionization should be given, eg, if negative ions are formed from sample molecules via resonance capture of thermal electrons generated in a chemical ionization source, this should be specified.
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chemical waste this category includes chemical waste that is regulated as hazardous waste, as well as unregulated chemical waste that poses a risk to health and to the environment Project: GP05 NOTE: Most chemical waste is regulated as hazardous waste. See hazardous waste.
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chemiluminescence immunoassay nonenzymatic chemical reaction that emits light, the amount of which can be related to the concentration of the analyte being measured Project: H59
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chemiluminescent assay an assay in which the signal is generated by a compound that emits light as the result of a chemical reaction
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chemiluminescent immunoassay an immunoassay in which the signal is generated by a compound that emits light as the result of a chemical reaction Project: M53
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chi square analysis statistical analysis that compares true positives, true negatives, false positives, and false negatives to establish probability (r-value) Project: ILA29 NOTE: The calculation can be used to compare methods, or to determine the strength of the relationship between test results and clinical outcomes, etc.
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chimerism when an organism has two or more different populations of genetically distinct cells Project: MM21 NOTE: In humans, this condition may be congenital or acquired through infusion of allogeneic hematopoietic cells during transplantation or transfusion.
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chimerism a chimera is an organism that has two or more different populations of genetically distinct cells. In humans, this condition may be acquired through infusion of allogeneic hematopoietic cells during transplantation or transfusion
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chip See microchip Project: ILA29
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chip reader instrument that reads the microscopic spots on a microarray chip and determines if they are positive or negative Project: ILA29
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chi-squared distribution the {parametric} probability distribution of a continuous random variable that can take any value from zero to infinity (ISO 3534-1/93-1.39) Project: ISO 3534
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chlorhexidine gluconate the digluconate salt of chlorhexidine Project: M47 NOTE: Used as a topical agent for cleansing and disinfecting the skin.
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chloridometer a coulometric titrator used to measure chloride ion concentration Project: C34
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cholesterol a sterol, of the formula C27H46O7 found in blood plasma bound to lipoproteins as well as in other body tissues
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chromatin deep staining DNA containing portion of the nucleus (protozoa) Project: M28
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chromatoidal bar deep-staining, bar-shaped, round, or splinter-shaped inclusions found in the cytoplasm of certain amoebae (Entamoeba spp.) Alternate Term: chromatoidal body Project: M28
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chromoblastomycosis a cutaneous or subcutaneous infection caused by darkly pigmented fungi (eg, Phialophora, Fonsecaea) characterized by the presence of dematiaceous sclerotic cells Project: M54
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chromogen (substrate) in Immunohistochemistry, a chromogen is used to localize bound antibody Project: I/LA28 NOTE: Chromogens are dissolved in a buffered substrate and when reacted with an appropriate enzyme, the substrate-chromogen produces a colored reaction product that specifically labels enzyme-linked immunoreactive substances in cells and tissues.
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chromogenic agar a differential agar growth medium for bacteria on which organisms of a particular species produce colonies of a unique color, which enhances their detection in clinical specimens that may contain multiple species of bacteria, eg, detection of methicillin-resistant Staphylococcus aureus in nasal swab specimens Project: M55
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chromogenic reagent reagent that reacts with certain chemical groups present or induced in cells and tissues with the formation of a coloured compound in situ (ISO 19001) Project: ISO 19001 EXAMPLE: Diazonium salt, Schiff’s reagent (ISO 19001).
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chromogenic substrate a substrate that generates a colored product in an enzyme-catalyzed reaction Project: DI01, ILA29
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chromosome a single, large DNA molecule with its associated proteins that contains many genes and functions to store and transmit genetic information Project: MM02, MM10, MM24
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chylothorax as a subtype of pleural fluid, indicates injury to the thoracic (lymphatic)duct with release of fat droplets/chylomicrons into the pleural space
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chylous effusion fluid resulting from chronic pleural effusion with breakdown of inflammatory cell membranes into cholesterol crystals NOTE 1: This fluid can appear iridescent and is sometimes referred to as “pseudochylous”; NOTE 2: The term “chylothorax” indicates the accumulation of fat droplets or chylomicrons in the pleural space due to thoracic (lymphatic) duct disruption or obstruction.
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ciphertext data that has been transformed by encryption so that its semantic information content (ie, its meaning) is no longer intelligible or directly available (See plaintext) (RFC 2828) Project: AUTO09
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circadian variation variations in physiological parameters, including blood analyte concentrations, which are related to cyclic events, ie, time of day, season of the year, and ingestion of meals Alternate Term: chronobiological variation, diurnal variation Project: C31
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circulating tumor cell cell that has detached from a primary tumor and circulates in the bloodstream Project: MM23 NOTE: These cells can constitute seeds for subsequent growth of additional tumors (metastasis) in different tissues.
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circulating tumor DNA free tumor DNA circulating in the plasma of patients with cancer Project: MM23 NOTE: The origin can include necrotic tumor cells shed from tumor deposits, cellular fragments, tumor-derived exosomes, or lysis of circulating tumor cells in the bloodstream.
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cis/trans these terms refer to the genetic phase (coupling/repulsion) of linked mutant alleles. In the cis phase, the individual is heterozygous at two neighboring loci and has the two mutations in question on the same chromosome. In the trans phase, the individual is heterozygous at two neighboring loci and has one of the two mutations in question on each of the two homologous chromosomes
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citrate agar electrophoresis electrophoresis in which the support medium is a citrate-containing agar gel
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civil air patrol (CAP) an organization congressionally charted to assist the Air Force and federal, state, and local agencies with emergency assistance; operations include humanitarian/disaster missions employing general aviation aircraft for transportation of important cargo, including medical supplies and blood NOTE 1: The Air Force Auxiliary, Civil Air Patrol, is composed of 61,000 volunteers in 1,700 communities nationwide, organized as 52 Wings (states/territories) and Squadrons (local); NOTE 2: CAP contact may be provided in the LEOP in your community; NOTE 3: Information may be accessed at: www.capnhq.org.
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clade See subtype Alternate Term: subtype Project: M53
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claimed microorganisms microorganisms that have been validated by the manufacturer and approved/cleared for reporting by a regulatory organization Project: M58
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classical pathway a series of sequential reactions among the components of complement, after their activation by antigen-antibody reactions or microbial products, in the order C1, C4, C2, C3, C5, C6, C7, C8, C9 Project: DI02
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classification organization of varied items into mutually exclusive but related classes Project: QMS04 NOTE: In the design process, fire rating, building type, biosafety type, and biological safety hoods are organized in this manner.
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clean catch specimen urine specimen that is collected from the middle of the urine stream after the first part of the flow has been voided Project: GP16 NOTE 1: Also known as “midstream” urine; NOTE 2: The urinary tract naturally contains bacteria that can contaminate a urine sample. The clean-catch method is used to prevent these bacteria from getting into the urine sample.
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cleaning process to remove any type of contamination, visible or not (ISO 15190) Project: ISO 15190, POCT13, POCT16
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clearance open space allowed adjacent to equipment to allow access for maintenance or airflow; open space allowed for staff to move freely and to accommodate disabled people Project: QMS04
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clerical error an incorrect transcription or improper use of the reporting medium leading to an unacceptable PT result
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CLIA '88 acronym for the Clinical Laboratory Improvement Amendments of 1988 (US CFR 493, February 28, 1992)
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clinical breakpoint 1) a classification based on an in vitro response of an organism to an antimicrobial agent at levels corresponding to blood or tissue levels attainable with usually prescribed doses; 2) susceptible clinical breakpoint – a category that implies that an infection due to the isolate may be appropriately treated with the dosage of an antimicrobial agent recommended for that type of infection and infecting species, unless otherwise contraindicated; 3) intermediate clinical breakpoint – a category that includes isolates with antimicrobial agent minimal inhibitory concentrations (MICs) or minimal effective concentrations (MECs) that approach usually attainable blood and tissue levels and for which response rates may be lower than for susceptible isolates; 4) resistant clinical breakpoint – a category that includes resistant isolates that are not inhibited by the usually achievable concentrations of the agent with normal dosage schedules or where clinical efficacy has not been reliable in treatment studies Project: M51
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clinical consultant an individual who is qualified to be a laboratory director who provides expertise regarding the appropriateness of the testing ordered and the interpretation of test results
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clinical cutoff a cutoff that is derived from any correlation between the minimal inhibitory concentrations of an antimicrobial agent(s) for a pathogen(s) and the clinical outcome Project: M23
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clinical decision point (critical value) decision limits determined on the basis of scientific and/or medical knowledge, often based on a medical condition
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clinical decision support system a health information technology system that is designed to provide physicians and other health care professionals with clinical decision-making tasks
Project: M39
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Clinical Document Architecture an HL7® v3 standard for the electronic representation of clinical documents Project: AUTO16
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clinical end point an outcome that represents direct clinical benefit, such as survival, decreased pain, or the absence of disease Project: H62 NOTE 1: Clinically meaningful end points that directly measure how a patient feels, functions, or survives; NOTE 2: End points that in themselves represent or characterize clinical outcome; objective outcomes include survival, disease exacerbation, and clinical event (eg, myocardial infarction or stroke); subjective outcomes include symptom score, and “health-related quality of life” (validated instrument); NOTE 3: Customarily, the basis for approval of new drugs.
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clinical evaluation (of in vitro diagnostic devices) an investigation of the clinical performance characteristics of a new (or new indication for use of) in vitro diagnostic assay in controlled clinical settings Project: I/LA21 NOTE 1: The term “clinical evaluation” (United States) is equivalent to the term “diagnostic evaluation” (Europe); NOTE 2: In Europe, as defined above, the term “diagnostic evaluation” is used. “Clinical evaluation” applies mostly to the evaluation of medical products, which are used on or in patients, or to clinical studies of drugs, under much more stringent conditions.
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clinical exposure-response cutoff the highest minimal inhibitory concentration at which efficacy, based on clinical end point, a microbiological end point, or other accepted surrogate of clinical end point, would be predicted in patients based on clinical exposure-response relationships using efficacy in infected patients and associated human pharmacokinetics Project: M23
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clinical exposure-response relationship the relationship of a favorable clinical response as a function of the drug concentration and minimal inhibitory concentration. It is expressed as the probability of a clinical response based on a clinically derived pharmacokinetic/pharmacodynamic predictor. Standard drug concentration–based exposure measures can be expressed as Cmax, area under the curve, Cmin, T>MIC, or other pharmacodynamic indices as defined by appropriate dose-fraction and exposure-response analyses and justified by the sponsor. Response refers to the direct measure of the pharmacologic effect of the drug and can be defined by a clinical end point, a microbiological end point, or other accepted surrogate of the clinical end point Project: M23
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clinical false-negative newborn screening result a screen negative result reported in an affected newborn Project: NBS06 NOTE: As used in NBS06, a screen negative result of a newborn screening algorithm (based on the detection of T-cell receptor excision circles with a value above the cutoff) reported for a newborn later diagnosed with severe combined immunodeficiency.
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clinical false-positive newborn screening result a screen positive result reported in an unaffected newborn Project: NBS06 NOTE: As used in NBS06, the positive result of a newborn screening algorithm (based on the absence of T-cell receptor excision circles or the detection of T-cell receptor excision circles at a value below the cutoff) that is obtained for a newborn who does not have severe combined immunodeficiency or severe T cell lymphopenia.
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clinical feasibility an evaluation performed using patient specimens to assess the potential application of a new assay to some clinical use Alternate Term: pilot evaluation Project: I/LA21 NOTE: Typically conducted by the sponsor, the evaluation may take place in a clinical setting or in the sponsor’s laboratory.
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clinical information information about the measurand that can be used to make a clinical or medical decision Project: EP35 NOTE: In CLSI EP35, clinical information can be, for example, the expected range of concentrations, inherent biological variability, medical decision levels, and any other relevant information for each specimen type.
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clinical information system any health care information system responsible for housing clinical information Project: POCT01 NOTE: Examples include laboratory information systems, clinical data repository, and electronic medical records.
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clinical information system any information system or computer system database responsible for housing clinical patient information Alternate Term: CIS Project: POCT02 NOTE: Examples include hospital information systems, laboratory information systems, clinical data repository, and electronic medical records.
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clinical interpretative criteria (clinical breakpoints) cutoff values designed to facilitate the prediction of clinical efficacy of a specified dose regimen, administered under specified conditions, for a specified target animal species, type of infection, and infecting organism. Clinical breakpoints provide numerical minimal inhibitory concentration or zone diameter values that can be used to categorize an isolate as susceptible, intermediate, or resistant, as defined below.For example, for antimicrobial X with interpretive criteria of: | | MIC (µg/mL) | Zone Diameter (mm) | | Susceptible | ≤ 4 | ≥ 20 | | Intermediate | 8–16 | 15–19 | | Resistant | ≥ 32 | ≤ 14 |
“Susceptible breakpoint” is 4 µg/mL or less; or 20 mm. or more.“Resistant breakpoint” is 32 µg/mL or greater; or 14 mm or less Project: VET04
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clinical interpretive criteria (clinical breakpoint) numerical minimal inhibitory concentration or zone diameter values used to indicate whether a clinical pathogen is susceptible, intermediate, or resistant to an antimicrobial Project: VET05
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clinical investigator a person under whose direction a clinical evaluation is conducted Project: I/LA21, ILA18
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clinical laboratories laboratories that perform patient tests and are evaluated on their ability to do so by proficiency testing programs NOTE 1: In addition to fulfilling the clinical laboratory’s regulatory requirements, proficiency testing can be used as a proactive quality improvement tool; proficiency test results can also be misleading when the program or the testing materials are not appropriate to the test methodology used by the laboratory; NOTE 2: Knowledge of appropriate programs and their optimal use are of importance to these stakeholders.
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clinical laboratory laboratory for the biological, microbiological, immunological, chemical, immunohematological, hematological, biophysical, cytological, pathological, genetic, or other examination of materials derived from the human body for the purpose of providing information for the diagnosis, management, prevention, and treatment of disease in, or assessment of the health of, human beings, and which may provide a consultant advisory service covering all aspects of laboratory investigation, including the interpretation of results and advice on further appropriate investigation (ISO 15189) Project: POCT07 NOTE 1: These examinations also include procedures for determining, measuring, or otherwise describing the presence or absence of various substances or microorganisms (ISO 15189); NOTE 2: In some jurisdictions, the term “medical laboratory” is used.
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clinical laboratory automation the integration of laboratory personnel and preanalytical (preexamination), analytical (examination), and postanalytical (postexamination) processes and information systems Project: AUTO01, AUTO02, AUTO12, AUTO14
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clinical laboratory automation systems an assemblage of components that mechanically and electronically transfers, analyzes, and processes information and material related to clinical diagnostic testing of patient specimens, controls, calibrators, standards, and images Project: AUTO01, AUTO02, AUTO12, AUTO14
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clinical laboratory reagent water water that has been purified to achieve specifications related to resistivity (ie, ≥ 10 MΩ • cm referenced to 25°C), microbial content (ie, total heterotrophic plate count ≤ 10 colony-forming units/mL), organic impurities (ie, total organic carbon < 500 ng/g [parts per billion]), and particulate count (ie, ≥ 0.22 µm at, or near, the output stage using a purification system that includes a stage that blocks the passage of particles) Project: C34
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clinical performance the capability of a binary examination to discriminate between subjects with and without a target condition Project: EP12 EXAMPLE: Discrimination between women who are pregnant and those who are not pregnant; NOTE 1: Clinical performance is commonly measured with parameters such as clinical sensitivity and clinical specificity; NOTE 2: Clinical performance can be affected by bias, imprecision, and how the binary decision is made.
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clinical performance the sum of all attributes that might be important for clinical use of results from a test method when applied to a specific intended use Project: EP19 NOTE: Performance specifications usually include clinical sensitivity and specificity, positive percent agreement and negative percent agreement, or other parameters of clinical usefulness.
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clinical relevance trait attributed to a genomic change or feature that is medically significant for diagnosis or management of a patient Project: MM09
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clinical reportable range the range of analyte values that a method can report as a quantitative result, allowing for specimen dilution, concentration, or pretreatment used to extend the direct analytical measurement range Project: C50, POCT09
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clinical sensitivity (for newborn screening) the proportion of newborns in the screened population who have the target disease and who have positive screening results Alternate Term: diagnostic sensitivity Project: NBS05, MM07, NBS13, NBS09, NBS06, NBS07, NBS10 Source: Newborn Screening Glossary EXAMPLE: In screening for cystic fibrosis, newborns with meconium ileus should be included in the calculation of sensitivity: Sensitivity = a / (a + c), in which a = a true-positive result and c = a false-negative result; NOTE 1: The clinical disease must be defined by criteria independent of the test under consideration; NOTE 2: The term “clinical sensitivity” (United States) is equivalent to “diagnostic sensitivity” (Europe); NOTE 3: Sensitivity = a / (a + c), for which a = true-positive screening test results and c = false-negative screening test results; see table in screening outcome; NOTE 4: “Clinical sensitivity” is not the same as “analytical sensitivity”; NOTE 5: Proportion of truly diseased persons in a screened population who are identified as diseased by the screening test. Sensitivity is a measure of the probability of correctly diagnosing a case, or the probability that any given case will be identified by the test. Infants with meconium ileus should be included in the calculation of sensitivity. Sensitivity = a / (a + c) where a = a true-positive result and c = a false-negative result; NOTE 6: In programs in which meconium ileus is excluded from the clinical sensitivity calculations, this deviation from the typical practice should be noted; NOTE 7: Clinical sensitivity refers to the assay’s ability to detect subjects with the condition or disease; NOTE 8: Clinical sensitivity is the fraction of clinically true positives divided by the sum of clinically true-positive plus clinically false-negative classifications; NOTE 9: As used in NBS06, clinical sensitivity refers to the ability of the newborn screening algorithm to identify subjects with severe combined immunodeficiency; NOTE 10: As used in NBS07, clinical sensitivity refers to the ability of the newborn screening algorithm to identify individuals with any form of Pompe disease; NOTE 11: See acylcarnitine.
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clinical sensitivity the ability of a test under study to give a positive result for subjects having the disease/state in question Project: I/LA28 NOTE: See and use the definition of the preferred term diagnostic sensitivity.
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clinical sensitivity the proportion of subjects with a well-defined clinical disorder whose test values are positive or exceed a defined decision limit (ie, a positive result and identification of the patients who have a disease) Project: MM01, GP10, ILA18, I/LA21, H26, MM06, M53, MM05, MM20, C49 NOTE 1: “Diagnostic sensitivity” is used in Europe and “clinical sensitivity” is used in the United States; NOTE 2: In Europe, the term “clinical” applies mostly to clinical studies of drugs, under much more stringent conditions; NOTE 3: Clinical sensitivity refers to the assay’s ability to detect subjects with the condition or disease; NOTE 4: It is the fraction of clinically true positives divided by the sum of clinically true-positive plus clinically false-negative classifications; NOTE 5: The clinical disorder must be defined by criteria independent of the test under consideration; NOTE 6: This term can also be defined as percent positivity in samples in which the target measurand (analyte) is known to be present (ie, derived from subjects with disease); NOTE 7: “Diagnostic sensitivity” is used outside of the United States and “clinical sensitivity” is used in the United States; NOTE 8: The term “clinical sensitivity” (United States) is equivalent to “diagnostic sensitivity” (Europe); NOTE 9: See seroconversion sensitivity.
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clinical sensitivity the ability of an examination to provide a positive result for subjects from the intended-use population who have the target condition (TC) for which they are being tested Alternate Term: sensitivity Project: EP12 NOTE 1: It is the proportion of subjects with the TC having a positive test result and is often expressed as a percentage; NOTE 2: Formerly, the term “diagnostic sensitivity” was used in CLSI documents.
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clinical sensitivity the ability of a test method under study to provide a positive result for subjects with the disease state or target condition in question Project: EP19
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clinical sensitivity the ability of a test under study to give a positive result for subjects having the disease/state in question or the proportion of subjects with a well-defined clinical disorder whose test values are positive or exceed a defined decision limit (eg, a positive result and identification of the patients who have a disease) Project: MM19, MM22, MM21, MM26 NOTE 1: The term “clinical sensitivity” (United States) is equivalent to “diagnostic sensitivity” (Europe); NOTE 2: In Europe, the term “clinical” applies mostly to clinical studies of drugs, under much more stringent conditions.
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clinical significance in the context of an evaluation of measurement procedure, the importance of an error due to its potential to alter a physician’s diagnosis, treatment, or management of a patient Project: C56
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clinical specificity (for newborn screening) the proportion of newborns in the screened population who do not have the target disease and who have negative screening results Alternate Term: diagnostic specificity Project: NBS09, NBS10 Source: Newborn Screening Glossary NOTE 1: The clinical disease must be defined by criteria independent of the test under consideration; NOTE 2: The term “clinical specificity” (United States) is equivalent to “diagnostic specificity” (Europe); NOTE 3: Specificity = d / (b + d), for which d = true-negative screening test results and b = false-positive screening test results; see table in screening outcome; NOTE 4: “Clinical specificity” is not the same as “analytical specificity”; NOTE 5: See positive predictive value.
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clinical specificity the ability of a test under study to give a negative result for subjects not having the disease in question or the ability of the test to correctly identify the absence of the disease at a particular decision threshold (ie, a negative result and idenification of patients who do not have a disease) (Centers for Disease Control and Prevention. Diagnostic Sensitivity and Specificity Job Aid. Accessed 12 April 2023. https://www.cdc.gov/labtraining/docs/job_aids/additional_resources/Sensitivity_and_Specificity_Final_5_23_2022_508.pdf) Alternate Term: diagnostic specificity (positive predictive value) Project: I/LA28, MM19, MM20, MM26 NOTE 1: Also known as diagnostic specificity (positive predictive value); NOTE 2: Clinical specificity refers to the assay’s ability to discriminate subjects who do not have the condition or disease from those who have the condition or disease; NOTE 3: It is the fraction of clinically true-negative classifications divided by the sum of clinically true-negative plus clinically false-positive classifications; NOTE 4: In laboratory testing, the ability of a test to give a negative result for patients who do not have the disease or condition for which they are being tested. It is measured as the ratio of negative tests to the total number of tests in those who do not have the disease or condition, and expressed as a percentage; NOTE 5: The term “clinical specificity” (United States) is equivalent to “diagnostic specificity” (Europe).
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clinical specificity the proportion of subjects who do not have a specified clinical disorder whose test results are negative or within the defined decision limit Project: MM06, I/LA21, MM01, MM22 NOTE 1: Clinical specificity refers to the assay’s ability to discriminate subjects who do not have the condition or disease from those who have the condition or disease; NOTE 2: It is the fraction of clinically true negative classifications divided by the sum of clinically true-negative plus clinically false-positive classifications; NOTE 3: In laboratory testing, the ability of a test to give a negative result for patients that do not have the disease or condition for which they are being tested; measured as the ratio of negative tests to the total number of tests in those that do not have the disease or condition; expressed as a percentage; NOTE 4: The term “clinical specificity” (United States) is equivalent to “diagnostic specificity” (Europe); NOTE 5: This term can also be defined as percent negativity in samples where the target analyte is known to be present (ie, derived from subjects without disease); NOTE 6: In Europe, the term “clinical” applies mostly to clinical studies of drugs.
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clinical specificity the ability of an examination to provide a negative result for subjects from the intended-use population who do not have the target condition (TC) for which they are being tested Alternate Term: specificity Project: EP12 NOTE 1: It is the proportion of subjects without the TC who have a negative test result and is often expressed as a percentage; NOTE 2: Formerly, the term “diagnostic specificity” was used in CLSI documents.
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clinical specificity the proportion of patients who do not have a specified clinical disorder whose test results are negative or within the defined decision limit Alternate Term: diagnostic specificity Project: MM07, H62 NOTE 1: The term clinical specificity (United States) is equivalent to diagnostic specificity (Europe); NOTE 2: Proportion of truly nondiseased persons who are so identified by the screening test. It is a measure of the probability of correctly identifying a nondiseased person with a screening test. Specificity = d / (b + d) where b = a false-positive result and d = a true-negative result; NOTE 3: Also referred to as “diagnostic specificity” (proportion of truly nondiseased persons who are so identified by the screening test); NOTE 4: It is measured as the ratio of negative test results in individuals without the target condition and is often expressed as a percentage; NOTE 5: The condition or characteristic of interest must be defined by criteria independent of the test under consideration.
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clinical specificity the ability of a test method under study to provide a negative result for subjects without the disease state or target condition in question Project: EP19
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clinical specimen See patient specimen Alternate Term: patient specimen; diagnostic specimen Project: M29
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clinical state a state of health or disease that has been defined by either a clinical definition or some other independent reference standard Project: EP24 NOTE: Examples of clinical states include “no disease found,” “disease 1” (where 1 represents the first clinical state under consideration), “disease 2” (where 2 represents the second clinical state under investigation), and so on.
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clinical testing diagnostic testing that is performed as part of a medical procedure Project: C52, C63 NOTE: Emergency departments, most hospital wards, and drug treatment programs are typical environments for this type of testing. In these situations, test results are needed to establish diagnoses, institute treatment, and monitor patient progress. Although a positive drug test result can lead to some type of legal action, clinical testing is not intended for forensic purposes.
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clinical utility value or benefit assigned to a particular outcome or state; diagnostic information that contributes to the identification of a particular condition or disease Alternate Term: diagnostic utility Project: MM17, I/LA28, MM19, MM20, MM22, MM23, MM24, MM26 NOTE 1: Clinical utility can encompass prognosis and monitoring response to therapy, as well as diagnosis; NOTE 2: Also known as diagnostic utility; NOTE 3: Clinical utility refers to the ability of an assay to improve clinical outcome measures compared with not using the assay.
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clinical validation the process through which test results are shown to be clinically meaningful, ie, finding whether the test is able to detect or predict the disorder or condition of interest in targeted patient groups Project: EP19
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clinical validation the process by which a clinical expert accepts and interprets the results of an order or an order group Project: AUTO16 NOTE 1: Interpretation of the results considers the results together with the biological history and the clinical and therapy information available for the patient; NOTE 2: This step may sometimes be performed by an expert system that uses knowledge rules and emulates the reasoning of the biomedical scientist, under its responsibility; NOTE 3: In HL7® Clinical Document Archictecture Release 2, this process is recorded as “authentication” of the laboratory report or of a subset of this report; NOTE 4: Also known as “medical validation.”
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clinical validity the accuracy with which a test predicts the presence or absence of a clinical condition or predisposition Project: MM17, MM19, MM20, MM23, I/LA28, MM26 NOTE 1: For genetic tests, the ability of a genotype to predict a phenotype associated with the clinical condition; NOTE 2: With immunohistochemistry assays, the clinical validity for the presence or absence of a biomarker in tissues to confirm the histogenesis (lineage) of a tumor, prognosis of a tumor, or prediction of the effectiveness of a therapeutic agent.
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clinical validity accuracy of detection of presence or absence of phenotype or disease
Project: H62
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clinical validity the strength of the relationship between a test and a clinical characteristic of interest Project: MM09 NOTE 1: Typically expressed as clinical sensitivity and clinical specificity; NOTE 2: For genetic tests, the correlation between the genotype and a clinical phenotype.
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clinically reportable interval the range of measurand values that a method can report as a quantitative result, allowing for specimen dilution, concentration, or other pretreatment used to extend the direct analytical measuring interval Project: H26
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clinically reportable range the range of analyte values that a method can report as a quantitative result, allowing for sample dilution, concentration, or other pretreatment used to extend the direct analytical measurement range Project: H57 NOTE 1: For example, if it is desired to report a result that exceeds the analytical measurement range, the specimen is commonly diluted to bring the analyte into that range, the diluted specimen is reassayed, and the final result calculated using the dilution factor; NOTE 2: The establishment of the clinically reportable range is a medical judgment made by the laboratory director, and is based in part on the assay technology.
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clinically significant antibody antibodies that have been associated with hemolytic disease of the fetus and newborn, a hemolytic transfusion reaction, or notably decreased survival of transfused red cells Project: I/LA33
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clinician provider of clinical services Project: GP49 NOTE: Clinicians are often physicians but may also be advanced practitioners, such as physician assistants, nurse practitioners, and midwives.
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clonal marker a marker that allows the identification of the progeny from a monoclonal cell proliferation, derived from a single cell (a clone)
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clone a population of identical units, organisms, cells, or individuals that derive from the same ancestral line Project: NRSCL8
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clone (as applied to a monoclonal antibody) the individual hybridoma cell line from which a monoclonal antibody is derived Project: I/LA28 NOTE: The hybridoma cells are separated into single cell isolates and clonally expanded from these individual single cells. Antibody is isolated from the clonally expanded populations and screened for function. Each cell in a hybridoma clone is identical, all sharing a single progenitor and, as such, produces an identical antibody.
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close call event or situation that could have resulted in an adverse event, accident, injury, or illness; but did not, either by chance or through timely intervention NOTE: Such events have also been referred to as near-miss incidents
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closed system reactions that occur in a single reaction vessel and require no separate postamplification analysis to generate a result Project: MM19
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closed system a system in which the manufacturer provides all hardware and software to the health care delivery organization Project: AUTO11 NOTE: Many medical devices are closed systems.
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closed-container sampling the action of aspirating a sample from a container/tube with the closure in place, requiring the sample probe to pierce the closure of the container/sample container Alternate Term: closed-tube sampling Project: AUTO01, AUTO02
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closed-tube sampling See closed-container sampling Project: AUTO02
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closure coating lubricant or other material applied to the container closure Project: GP39
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clot activator material used to initiate the clotting mechanism Project: GP39, GP34
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clot reaction curve graphical (visual) representation of the clotting reaction measuring the optical output data recorded during clotting tests (eg, prothrombin time, activated partial thromboplastin time, factor assays) Project: H48
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cloud a software model in which data, resources, and the software are shared and provided to clients over the Internet, based on demand Project: AUTO11
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cloud storage a computing model in which data are stored on remote servers accessed from the Internet Project: QMS26, QMS22
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CLSI Clinical and Laboratory Satandards Institute (formerly NCCLS [until 1 January 2005]: National Committee for Clinical Laboratory Standards)
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CLSI standard a document developed through the consensus process that clearly identifies specific, essential requirements for materials, methods, or practices for use in an unmodified form NOTE: A standard may, in addition, contain discretionary elements, which are clearly identified.
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cluster of differentiation system the identification of monoclonal antibodies with similar patterns of reactivity with human cells, which was the focus of numerous international workshops Alternate Term: CD system Project: H43, H42, H52 NOTE: Each group of antibodies was assigned a cluster of differentiation number. Not all antibodies in a cluster of differentiation group react with identical portions (epitopes) of their target antigen. An antigen recognized by a given cluster of antibodies (eg, CD4) is referred to as a “cluster of differentiation antigen” (eg, CD4 antigen). An antibody that belongs to a given cluster is referred to as cluster of differentiation “x,” with the manufacturer’s nomenclature given in parentheses (eg, CD4 [Leu3a]).
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Cmax the maximum (or peak) serum concentration that a drug achieves after the drug has been administered and before the administration of a second dose Project: M23
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Cmax/minimal inhibitory concentration the peak drug concentration divided by the minimal inhibitory concentration Project: M23 NOTE: When the Cmax/minimal inhibitory concentration is reported, the point at which the calculation was determined (eg, after the first dose, day 1, or at steady-state) should be stated.
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Cmin the minimum blood plasma concentration reached by a drug before administration of a second dose Project: M23
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coagulation the process by which the coagulation factors in blood interact to form a clot Project: POL1/2
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coagulation factor one of a group of components of blood plasma that interact to form a blood clot Project: H47, H48
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coagulation factors the various components of the blood coagulation system Project: H21 NOTE: The following factors (including synonyms which are, or were in use) are known:
Factor I (fibrinogen)
Factor II (prothrombin)
Factor III (commonly termed thromboplastin, tissue factor)
Factor IV (commonly termed calcium)
Factor V (labile factor)
Factor VII (stable factor)
Factor VIII (labile, antihemophilic factor, antihemophilic globulin, antihemophilic factor A, Factor VIII:C)
Factor IX (plasma thromboplastin component, Christmas factor, antihemophilic factor B)
Factor X (Stuart factor, Prower factor, Stuart-Prower factor)
Factor XI (plasma thromboplastin antecedent, antihemophilic factor C)
Factor XII (Hageman factor, surface factor, contact factor)
Factor XIII (fibrin stabilizing factor, fibrin stabilizing enzyme, fibrinase)
Other factors: (prekallikrein [Fletcher factor], high-molecular-weight kininogen [Fitzgerald factor])
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coagulation meter device to assess the clotting time Project: POCT07
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coagulation test system a device used to measure the rate of blood or plasma clotting Project: POCT14
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coagulometer an analytical instrument for measuring coagulation parameters Alternate Term: coagulation analyzer Project: H57
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cocktail a mixture of two or more monoclonal antibodies or fluorescent reagents Project: H52
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cocktail immunoassay testing a practice in which multiple specimens are combined and tested as one, or multiple antibodies to different drug classes are combined in an effort to reduce the total number of analytical tests Project: C52 NOTE 1: If any cocktailed specimens are positive then the original specimens are retested to determine which particular specimen(s) is positive; NOTE 2: If any cocktailed reagent produces a positive result for a particular specimen, then the original specimen(s) is retested with an individual reagent(s) to determine which specific drug is present.
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cocktailing process of combining two or more monoclonal antibodies or fluorescent reagents Project: H52
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Code of Federal Regulations Published by the Office of the Federal Register, National Archives and Records Administration as a special edition of the Federal Register
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code set any set of codes used for encoding data elements, such as tables of terms, medical concepts, medical diagnosis codes, or medical procedure codes Project: AUTO16 NOTE: An example of an international code set is LOINC® (Logical Observation Identifiers Names and Codes).
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codes a collection of laws in writing Project: QMS04
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coding a process that adjusts the glucose meter to use the proper calibration Project: POCT13
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coefficient in the context of quantitative medical laboratory measurement procedures, the calculated values for B (subscript 0 through 4) for the multiple linear regression equation Project: EP10
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coefficient of determination the square of the correlation coefficient Alternate Term: Determination coefficient Project: NRSCL08
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coefficient of variation standard deviation divided by the mean (ISO 3534-1) Project: EP10, C24, H57, H26, MM06, C51, QMS24, EP31, MM17, QMS23 NOTE 1: The ratio may be expressed as a percentage; NOTE 2: The term “relative standard deviation” is sometimes used as an alternative to “coefficient of variation” but this use is not recommended; NOTE 3: Coefficient of variation is often multiplied by 100 and expressed as a percentage; NOTE 4: It is a measure of relative imprecision; it is often multiplied by 100 and expressed as a percentage and abbreviated as “% CV”; NOTE 5: It is calculated as 100 times the standard deviation, divided by the mean, and expressed as a percentage; NOTE 6: The coefficient of variation is commonly reported as a percentage; NOTE 7: The predecessor term “relative standard deviation” is deprecated by the term coefficient of variation; NOTE 8: For a non-negative characteristic, the ratio of the standard deviation to the average; NOTE 9: A measure of relative precision.
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coefficient of variation a measure of relative precision Project: H62 NOTE 1: For a non-negative characteristic, the ratio of the standard deviation to the average; NOTE 2: It is often multiplied by 100 and expressed as a percentage.
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coefficient of variation for a non-negative characteristic, standard deviation divided by the mean (modified from ISO 3534-1) Project: EP33 NOTE: It is often multiplied by 100 and expressed as a percentage.
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coenocytic aseptate with no or rare cross-walls separating the cells Project: M54 NOTE: Examples include Mucorales, Entomophthorales, and Pythium spp.
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coenzyme a small nonprotein substance required in an enzyme reaction Project: NRSCL8 NOTE: Some coenzymes are also substrates.
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cofactor a nonsubstrate coenzyme Project: DI01
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cognitive error error of incorrect choices, owing to insufficient knowledge, misinterpretation of available information, or application of the wrong cognitive rule (ISO/TS 22367) Project: ISO/PDTR 22367
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cognitive error error made from mistakes in decision-making and problem-solving NOTE: Mistakes typically involve insufficient knowledge, failure to correctly interpret available information, or application of the wrong cognitive rule
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coherent derived unit derived unit that, for a given system of quantities and for a chosen set of base units, is a product of powers of base units with no other proportionality factor than one (JCGM 200:2012) Project: ISO IEC Guide 99 NOTE 1: A power of a base unit is the base unit raised to an exponent (JCGM 200:2012); NOTE 2: Coherence can be determined only with respect to a particular system of quantities and a given set of base units; EXAMPLE 1: If the metre, the second, and the mole are base units, the metre per second is the coherent derived unit of velocity when velocity is defined by the quantity equation v = dr/dt, and the mole per cubic metre is the coherent derived unit of amount-of-substance concentration when amount-of-substance concentration is defined by the quantity equation c = n/V. The kilometre per hour and the knot, given as examples of derived units in 1.11, are not coherent derived units in such a system of quantities (JCGM 200:2012); NOTE 3: A derived unit can be coherent with respect to one system of quantities but not to another; EXAMPLE 2: The centimetre per second is the coherent derived unit of speed in a CGS system of units but is not a coherent derived unit in the SI (JCGM 200:2012); NOTE 4: The coherent derived unit for every derived quantity of dimension one in a given system of units is the number one, symbol 1. The name and symbol of the measurement unit one are generally not indicated (JCGM 200:2012).
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coherent system of units system of units, based on a given system of quantities, in which the measurement unit for each derived quantity is a coherent derived unit (JCGM 200:2012) Project: ISO IEC Guide 99 EXAMPLE: Set of coherent SI units and relations between them (JCGM 200:2012); NOTE 1: A system of units can be coherent only with respect to a system of quantities and the adopted base units (JCGM 200:2012); NOTE 2: For a coherent system of units, numerical value equations have the same form, including numerical factors, as the corresponding quantity equations (JCGM 200:2012).
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cohort study type of observational study design in which determination of exposure precedes determination of outcome Project: GP45 NOTE 1: In this study design, subsets of a defined population are identified who are, have been, or in the future may be exposed or not exposed, or exposed in different degrees, to a factor or factors hypothesized to influence the possibility of occurrence of a given disease or other outcome of interest; NOTE 2: The main feature of cohort study is observation of large numbers over a long period (commonly years) with comparison of incidence rates in groups that differ in exposure levels. An essential feature of the method is observation of the population for a sufficient number of person-years to generate reliable incidence or mortality rates in the population subsets. This generally implies study of a large population, study for a prolonged period (years), or both. The denominator may be persons or person-time; NOTE 3: Cohort studies may be conducted prospectively, as described above, or “retrospectively” as historical cohort studies. Such studies use existing records about the health or other relevant aspects of a population as it was at some time in the past and determines the current (or subsequent) status of members of this population with respect to the condition of interest.
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coin lesion a well-circumscribed, calcified lung lesion resembling the shadow of a coin on an x-ray
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cold ischemia time the time from removal of the specimen from the body, when it is at body temperature, to the time it is stabilized; this time represents the period when the devascularized tissue is at room temperature or lower (eg, refrigerated) Project: MM13
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cold temperature a temperature maintained thermostatically between 2 and 8°C (36 to 46°F). Project: M40
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collection device (for newborn screening) a medical device used to collect blood spots for routine newborn screening Alternate Term: specimen collection device Project: NBS01, NBS09, NBS05, NBS10 Source: Newborn Screening Glossary NOTE 1: The collection device has two components: a section for recording demographic and other requested information and a blood collection (specified filter paper) section with preprinted circles to be filled with the newborn blood drops; NOTE 2: If a preprinted circle is not present, local requirements must define the quantity of blood considered acceptable; NOTE 3: Once the blood is collected, the collection device becomes the specimen (also referred to as “blood spot specimen” or “dried blood spot specimen”) and is no longer considered a collection device; NOTE 4: This specimen collection device is also commonly referred to as a “Guthrie card,” “filter paper,” or a “blood spot card”; NOTE 5: See dried blood spot.
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collection vessel any tube or container, preferably plastic, which serves to contain the body fluid specimen Project: H56
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collision-induced dissociation dissociation of an ion after collisional excitation (IUPAC 2006) Project: C43
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collision-induced dissociation a process wherein a (fast) projectile ion is dissociated as a result of interaction with a target neutral species Alternate Term: collisionally activated dissociation; CAD Project: C50 NOTE: This is brought about by conversion, during the collision, of part of the ion’s translational energy to internal energy.
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colloid small, solid particles that will not settle out of a solution Project: GP40
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color compensation a mathematical or electronic correction applied to flow cytometric data to account for the overlapping fluorescence emission from one fluorochrome in the wavelength region where the second is measured Project: H43, H42 NOTE: Compensation is achieved by subtracting a fraction of one measured fluorescence signal from each of the other fluorescent signals, the amount for subtraction determined from appropriate single-stained controls. The number of signals involved is equal to the number of fluorochromes (N) used and the number of compensation coefficients to be determined represented by an N x N dimensional matrix. The result is that each corrected signal reflects the emission of a single fluorochrome.
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color compensation in flow cytometry, electronic or mathematical subtraction of a fraction of one signal from a second Project: NRSCL8 NOTE: Used in correcting for overlapping fluorescence from one fluorochrome in the wavelength region where the second is to be measured so that populations stained exclusively with each fluorochrome appear at right angles to each other.
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color compensation mathematical (software) or electronic correction applied to flow cytometric data to account for the overlapping fluorescence emission from one fluorochrome in the wavelength region where the second is measured Project: H52 NOTE: Compensation is achieved by subtracting a fraction of one measured fluorescence signal from each of the other fluorescent signals, the amount for subtraction determined from appropriate single-stained controls. The number of signals involved is equal to the number of fluorochromes (N) used and the number of compensation coefficients to be determined, represented by an N × N dimensional matrix. The result is that each corrected signal reflects the emission of a single fluorochrome.
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colorimeter an instrument used for color measurement based on optical comparison with standard colors Project: ASTM08, VET04, VET03
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colorimetry the measurement and analysis of color by comparison with a standard Project: POL1/2
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colposcopy a procedure where a dissecting-type microscope is used to view the cervix following an application of dilute acetic acid, which colors the cervical intraepithelial neoplasia lesions transiently white (acetowhite) and/or accentuates abnormal vasculature to facilitate the identification of intraepithelial lesions and cancer for biopsy Project: GP15 NOTE 1: Colposcopy is done following an abnormal Pap test result, or in the investigation of symptoms of cervical pathology such as abnormal vaginal bleeding, even if the Pap test is reported as normal. Colposcopy allows illuminated examination of the lower genital tract to detect epithelial abnormalities and assess severity of these lesions; NOTE 2: Colposcopy is also done when the cervix is visually abnormal in appearance, and when a high-risk human papillomavirus test is positive in the following clinical situations: 1) postcolposcopy follow-up of women treated for cervical intraepithelial neoplasia 2,3; 2) postcolposcopy follow-up of women not found to have cervical intraepithelial neoplasia 2,3 or adenocarcinoma in situ at initial colposcopy and referred for the evaluation of repeat atypical squamous cells of undetermined significance, atypical squamous cells—cannot exclude high-grade squamous intraepithelial lesion, low-grade squamous intraepithelial lesion, and atypical glandular cells not otherwise specified; and 3) follow-up of women age 30 and over having a normal Pap and a positive high-risk human papillomavirus test on the initial screen, and either a positive high-risk human papillomavirus test and/or an abnormal Pap on the 12-month follow-up exam.
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combination antimicrobial agent consists of two agents in a single compound in which at least one agent has antimicrobial activity. For antimicrobial susceptibility testing, the two agents are tested together in a single tube or well, plate, or disk. If only one agent has antimicrobial activity, that agent is listed first. For example, if drug A is a β-lactam and drug B is a β-lactamase inhibitor without antimicrobial activity, the combination is presented as A/B. For minimal inhibitory concentration tests, the concentrations of the agents are tested at a defined ratio over a series of dilutions or with one agent held constant and the other serially diluted. For example: • Defined ratio of 2:1 (µg/mL): 128/64, 64/32, 32/16, 16/8, 8/4, 4/2, 2/1, 1/0.5 • One agent constant at 4 (µg/mL): 128/4, 64/4, 32/4, 16/4, 8/4, 4/4, 2/4 Project: M23 NOTE: When minimal inhibitory concentration values from combination antimicrobial agents are reported, it is preferred that the concentration of the first agent in the combination is reported.
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combination immunoassay an immunoassay that detects both antigen and antibody Project: M53
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combined standard measurement uncertainty standard measurement uncertainty that is obtained by combining the individual standard measurement uncertainties associated with the input quantities in a measurement model Alternate Term: combined standard uncertainty Project: C51, EP32 NOTE: The symbol for a combined standard measurement uncertainty of the quantity y is uy or u(y).
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combined standard uncertainty (measurement) standard measurement uncertainty that is obtained using the individual standard measurement uncertainties associated with the input quantities in a measurement model (JCGM 200:2012) Alternate Term: combined standard measurement uncertainty Project: ISO IEC Guide 99, EP29, EP30 NOTE 1: In case of correlations of input quantities in a measurement model, covariances must also be taken into account when calculating the combined standard measurement uncertainty (JCGM 200:2012); NOTE 2: The symbol for a combined standard measurement uncertainty of the quantity y is uy or u(y) (JCGM 100:2008).
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combustible liquid a liquid with a flash point of 38°C (100°F) or higher, but generally below 93.3°C (200°F) Project: QMS04
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commercial in vitro diagnostic device an in vitro diagnostic kit or reagent that has been validated by a commercial manufacturer to produce clinically meaningful results under very specific preexamination and examination conditions Project: MM07 NOTE: Deviation from those conditions may affect the results obtained with the in vitro diagnostic device.
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commercial manufacturer an entity that intends to put a test method or any of its components into distribution beyond its operational location. It implies that the entity complies with all local or regional regulation necessary to legally place the materials on the market. These are often referred to as in vitro diagnostic devices Project: EP19
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committee a group of people appointed or chosen to perform a function on behalf of a larger group Project: QMS14 Source: Quality Glossary
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committee charter rights delegated to a committee including scope of activity and terms of reference Project: QMS14
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common access point an access point that can service medical information bus, point-of-care, and hand-held personal digital assistant devices Project: POCT01
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common blood coagulation pathway the end phase of the coagulation cascade, which involves the activation of factor X by tissue factor/VIIa complex and/or factor IXa, and the subsequent activation of factor II and conversion of fibrinogen to fibrin Project: POCT14
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common carrier company or utility publicly and indiscriminately engaging in the regular business of transporting people or freight, under license or authority of a regulatory body Project: GP36 NOTE: A common carrier is distinguished from a contract carrier, which serves specific clients.
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common cause variation variation resulting from sources inherent in the testing process NOTE: Also known as "random variation" or "process variation".
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common determinant a cluster of epitopes that identify related antigens Project: NRSCL8 NOTE: The C1 portion of light chains from immunoglobulins IgG, IgA, IgM, IgD, and IgE; or the portion of IgH chains that is identical in humans, monkeys, goats, and rabbits.
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communicable disease an illness due to a specific infectious agent or its toxic products that arises through transmission of that agent or its products from an infected person, animal, or reservoir to a susceptible host, either directly or indirectly through an intermediate plant or animal host, vector, or the inanimate environment Alternate Term: infectious disease Project: POCT16
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communication exchange and flow of information and ideas Project: QMS16 NOTE: Communication is a process by which information is exchanged between individuals through a common language or system of symbols, signs, or behavior.
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commutability (of a material) closeness of agreement between the mathematical relationship of the measurement results obtained by two measurement procedures for a stated quantity in a given material and the mathematical relationship obtained for the quantity in routine samples (ISO 18153) Project: ISO 17511, ISO 18153, ep21, C64, EP39 NOTE: For reference materials used to calibrate measurement procedures intended for use by medical laboratories, the routine samples shall include samples from healthy and relevantly diseased individuals.
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commutability (of a material) ability of a material to yield the same numerical relationships between results of measurements by a given set of measurement procedures, purporting to measure the same quantity, as those between the expectations of the relationships obtained when the same procedures are applied to other relevant types of material (ISO 15198) Project: ISO 15194, ISO 15198, ISO 15197, ISO DIS 17593, ISO DIS 18113-1 NOTE 1: This means that two different measurement procedures calibrated with the same material will yield equivalent results for representative samples of the type intended to be measured (ISO/DIS 18113-1); NOTE 2: The material in question is usually a calibrator (ISO/DIS 18113-1); NOTE 3: At least one of the two given measurement procedures is usually a high-level measurement procedure (ISO 15197, ISO/DIS 17593).
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commutability the equivalence of the mathematical relationships among the results of different measurement procedures for a reference material and for representative samples of the type intended to be measured Project: EP10 NOTE: This is equivalent to the ISO definition, ie, closeness of the agreement between the mathematical relationship of the measurement results obtained by two measurement procedures for a stated quantity in a given material, and the mathematical relationship obtained for the quantity in routine samples.
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commutability property of a reference material, demonstrated by the closeness of agreement between the relation among the measurement results for a stated quantity in this material, obtained according to two given measurement procedures, and the relation obtained among the measurement results for other specified materials (JCGM 200:2012) Project: ISO IEC Guide 99, MM06, EP23, EP29, EP26, C62, C64, QMS24, EP34, EP32 NOTE 1: The reference material in question is usually a calibrator, and the other specified materials are usually routine samples (JCGM 200:2012); NOTE 2: The measurement procedures referred to in the definition are the one preceding and the one following the reference material (calibrator) in question in a calibration hierarchy (JCGM 200:2012, ISO 17511); NOTE 3: The stability of commutable reference materials should be monitored regularly (JCGM 200:2012); NOTE 4: A commutability statement is restricted to the measurement procedures as specified in a particular comparison (ISO 17511); NOTE 5: In commutability assessment of a reference material, comparisons among all applicable measurement procedures is desirable; NOTE 6: Closeness of agreement of measurement results is defined in terms of fitness for purpose as appropriate for the intended use of the reference material.
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commutability (of a reference material) property of a reference material, demonstrated by the equivalence of the mathematical relationships among the results of different measurement procedures for a reference material and for representative samples of the type intended to be measured Project: EP30
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commutability (of a material) property of a given reference material, demonstrated by the closeness of agreement between the relation among the measurement results for a stated quantity in this material, obtained according to two measurement procedures, and the relation obtained among the measurement results for other specified materials (ISO 15194) Project: ISO 15194, EP14 NOTE 1: The reference material in question is usually a calibrator and the other specified materials are usually routine samples (ISO 15194); NOTE 2: The measurement procedures referred to in the definition are the one preceding and the one following the reference material (calibrator) in question in a calibration hierarchy (ISO 15194); NOTE 3: For EP14, other specified materials are patient samples intended to be measured by an in vitro diagnostic medical device.
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commutable interassay properties of a reference material, calibrator material, or quality control material that are comparable with those demonstrated by authentic clinical specimens Project: prEN 12287, C37, EP31 NOTE: Commutability of a material is defined as the “degree to which a material yields the same numerical relationships between results of measurements by a given set of measurement procedures, purporting to measure the same quantity, as those between the expectations of the relationships obtained when the same procedures are applied to other relevant types of material” (CEN prEN 12287:1999, 3.5).
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commutable the attribute of acceptable commutability in a reference material, calibrator, control, or other process sample matrix Project: EP10
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companion diagnostic device an in vitro diagnostic device or an imaging tool that provides essential information for the safe and effective use of a corresponding therapeutic product Project: MM23 NOTE: The use of an in vitro diagnostic companion diagnostic device with a particular therapeutic product is stipulated in the instructions for use in the labeling of both the diagnostic device and the corresponding therapeutic product, as well as in the labeling of any generic equivalents and biosimilar equivalents of the therapeutic product; EXAMPLE: A BRAF testing kit is an in vitro diagnostic device intended for the qualitative detection of the BRAF V600E and V600K variants in DNA samples extracted from formalin-fixed, paraffin-embedded human melanoma tissue. It is intended to be used as an aid to select melanoma patients with tumors that have this variant and who are most likely to respond favorably to specific targeted therapy agents.
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comparability closeness of the agreement between the results of the coagulometer/reagent system under evaluation with an established method Project: H57
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comparability agreement between patient results obtained for an analyte (measurand) using different measurement procedures within a health care system Project: H26, EP31 NOTE: The results are considered to be comparable if the differences do not exceed a critical value established based on defined acceptance criteria.
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comparative FTH measurement procedures rely on use as calibrants of serum containing various total hormone concentrations, in which the corresponding free thyroid hormone concentration is established by an absolute measurement procedure Project: C45
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comparative measurement procedure a well-characterized measurement procedure that serves as the basis for assigning the true concentration of an analyte in a sample in an evaluation of a measurement procedure Project: EP07
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comparative measurement procedure measurement procedure whose performance characteristics are considered suitable for clinical use and with which a candidate measurement procedure can be compared to evaluate the latter’s suitability for clinical use Project: EP27
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comparative measurement procedure measurement procedure used as the basis for comparing two different measurements (eg, in the evaluation of total analytical error) that ideally is traceable to a reference measurement procedure
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comparative method in a method evaluation experiment, a well-characterized method that serves as the basis for assigning the true concentration of an analyte in a sample NOTE 1: The method(s) being used to validate the new automated system, also known as a comparator method; NOTE 2: The comparative method(s) may be a reference standard or a nonreference standard.
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comparative method the measurement procedure used as the basis for comparing two different measurement procedures (eg, in the evaluation of matrix effects) NOTE: The more specific this procedure is, the better the conclusion with regard to the source of the observed interference.
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comparative method the method used as the basis for comparing two methods, eg, in the evaluation of matrix effects NOTE: The more specific this method is, the better the conclusion with regard to the source of the observed interference.
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comparative tube blood collection tube currently used by the clinical laboratory Project: GP34
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comparator measurement procedure measurement procedure used as the basis for comparing two different measurements (eg, in the evaluation of total analytical error) that ideally is traceable to a reference measurement procedure Project: EP21
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comparator method method against which a new system is evaluated Project: M52 NOTE: Comparator methods may include reference methods or a previously verified US Food and Drug Administration–cleared commercial system.
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comparison method measurement procedure method that a continuous glucose monitoring measurement is compared with
Project: POCT05 NOTE: This term is commonly known in the CGM industry as “reference method.” The term “reference method” is often used synonymously with a comparison method or a comparator.
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comparison of methods a statistical procedure that is based on data gathered from the paired analysis of the same samples by two different measurement procedures Project: EP10 NOTE: Ideally, one of the procedures is a well-accepted or reference measurement procedure, sometimes called a “gold standard.”
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compatibility testing for the purposes of this document, meaning is limited to the serological crossmatch; procedure that involves combining of recipient serum or plasma with donor red blood cells to demonstrate ABO and/or other clinically significant antibody incompatibility Project: I/LA33
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compensation matrix the mathematical inverse of the spillover matrix. The values of the compensation matrix are used to correct the spectral overlap resulting in fluorescence spillover Project: H62 NOTE: See spillover matrix, fluorescence compensation, and spectral overlap.
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competence demonstrated ability to apply knowledge and skills to achieve intended results Project: QMS03, QMS13, QMS01 Source: Quality Glossary
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competence ability to apply knowledge and skills to achieve intended results (ISO 9000) Alternate Term: competency Project: HS02, POCT10, GP23, GP48
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competence assessment evaluation of a person’s ability to perform a test and to use a testing device Project: POCT08, POCT15 NOTE: Competence assessment includes all aspects of testing, from specimen collection to results reporting, and it is usually performed with specimens or samples containing known amounts of the analytes for which the specimens or samples are being tested.
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competence assessment evaluation of a person’s ability to apply his or her skill, knowledge, and experience to perform assigned laboratory duties correctly Project: QMS16, POCT04, QMS03 Source: Quality Glossary NOTE: This includes all aspects of testing, from specimen collection to result reporting, and it is usually done with specimens containing known amounts of the analyte(s) for which the specimens are being tested.
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competencies the capability to apply or use a set of related knowledge, skills, and abilities required to successfully perform “critical work functions” or tasks in a defined work setting Project: QMS16 Source: Quality Glossary
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competency the circumstance to have demonstrated and documented the ability to correctly perform testing using a point-of-care blood glucose meter system Project: POCT12
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competency following successful completion of a training program, the assessment of a person’s ability to perform blood glucose testing Project: POCT13, POCT17
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competency assessment evaluation of a person’s ability to perform a test including all aspects of testing, from specimen collection to result reporting
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competitive assay an assay based on the competition of labeled and unlabeled analytes for a receptor Project: DI01, I/LA23
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complaint any concern about the laboratory’s operation Project: QMS21 Source: Quality Glossary EXAMPLES: Quality of testing, unlabeled specimens, unethical practices, confidentiality of patient information, laboratory qualification, and responsibility issues.
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complement a group of plasma proteins, some of which are enzymes, that are sequentially activated by antigen-antibody complexes or microbial products Project: DI01
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complement fixation an immunoassay that uses the complement-mediated lysis of cells to detect the occurrence of an antigen-antibody reaction Project: DI01
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complementary the property of two strands of nucleic acid that can hybridize by specific-base pairing between the nucleotides Project: MM01, MM09, MM10, MM12, MM22, MM24
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completeness the property that all necessary parts of the entity are included Project: AUTO08 NOTE: Completeness of a product is often used to express the fact that all requirements have been met by the product (NBS Special Publication 500-75).
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compliance successful fulfillment of a rule, such as a specification, standard, policy, regulation, or law Project: QMS15, QMS01 Source: Quality Glossary NOTE: For the purposes of QMS15, compliance means complying both with regulatory and accreditation requirements and with the laboratory’s approved policies, processes, and procedures.
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compliance successful fulfillment of a requirement Project: QMS17
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compliance the act or process of complying to a desire, demand, proposal, or regimen, or to coercion (Merriam Webster) Project: C52 NOTE: In C52, compliance refers to, 1) patient adherence to a clinician’s prescription for a drug regimen, and 2) patient adherence to his or her pain management “contract” that he or she signs with the clinician.
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component part of a finished, packaged, and labelled in vitro diagnostic medical device (ISO 18113-1) Project: ISO 18113-1, ISO 18113-2, ISO 18113-3, POCT07 NOTE 1: Typical kit components include antibody solutions, buffer solutions, calibrators, and/or control materials (ISO 18113-1); NOTE 2: Adapted from US Code of Federal Regulations (CFR), Title 21, Part 820 — Quality System Regulation (ISO 18113-1); EXAMPLE: Raw material, substance, piece, part, software, firmware, labeling, or assembly (ISO 18113-1).
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component field a single data element or data elements which express a finer aggregate or extension of data elements which precede it; for example, parts of a field or repeat field entry Project: LIS02 NOTE 1: As an example, the patient’s name is recorded as last name, first name, and middle initial, each of which is separated by a component delimiter; NOTE 2: Components cannot contain repeat fields.
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compound heterozygote the presence of two different mutant alleles at a particular gene locus, one on each chromosome of a pair Project: MM01 NOTE: A mutation affecting only one allele is called heterozygous. A homozygous mutation is the presence of the identical mutation on both alleles of a specific gene. However, when both alleles of a gene harbor mutations, but the mutations are different, these mutations are called compound heterozygous. This is important, for example, in recessive diseases in which each allele carries a different mutation, one from each parent.
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comprehensive CLIA QC the process of testing every substrate and/or reagent that is part of a microbial identification system for positive and negative reactivity, using biologic quality control organisms, with each batch, lot number, and shipment of microbial identification system Project: M50
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computer system security the protection of computer hardware and software from accidental or malicious access, use, modification, destruction, or disclosure Project: AUTO08 NOTE: Security also pertains to personnel, data, communications, and the physical protection of computer installations (IEEE 610.12-1990).
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concentrate the liquid containing dissolved and suspended matter that concentrates on one side of a membrane Project: GP40
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concentration (for antimicrobial agent properties) amount of an antimicrobial agent in a defined volume of liquid (ISO 20776-1) Project: ISO 20776-1 NOTE 1: The concentration is expressed as mg/L (ISO 20776-1); NOTE 2: mg/L = µg/mL, but it is not recommended to use the unit µg/mL (ISO 20776-1).
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concentration a measure of the amount of dissolved substance per unit of volume (RHUD1.7CD) Project: VET03
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concentration of total hemoglobin the concentrational (mass concentration, substance concentration) amounts of the total of all forms of hemoglobin present in the sample
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concentration techniques procedures, usually in fecal examinations, allowing the examination of large amounts of feces (flotation or sedimentation procedures; some available for blood specimens and urine specimens) Project: M28
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condenser the stage of a distillation system that removes sufficient heat from a vaporized liquid to cause the vapor to change to a liquid phase Project: GP40
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condition of interest a particular disease, disease stage, health status, or any other identifiable condition within a patient, such as staging a disease already known to be present, or a health condition that should prompt clinical action, such as the initiation, modification, or termination of treatment (defined in Standards for Reporting of Diagnostic Accuracy Initiative) Alternate Term: target condition Project: MM17
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condition of interest a particular disease, a disease stage, health status, or any other identifiable condition or characteristic of interest within a subject, such as staging a disease already known to be present, or a health condition that could prompt clinical action, such as the initiation, modification, or termination of treatment Alternate Term: target condition, event of interest Project: EP12 NOTE: For analyte-detection examinations, TC can be generalized as the subject having the analyte (eg, virus).
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conditional safety safety aspects of medical devices dependent on proper use, handling, testing, or installation of the devices, provided by the manufacturer alone or in combination with service providers, such as contract sterilizers and practitioners (ISO Guide 63-2.2) Project: ISO Guide 63-2.2
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conduction the flow of heat by conduction occurs via collisions between atoms and molecules in the substance and the subsequent transfer of kinetic energy Project: GP28 NOTE: When there exists a temperature gradient within a body, heat energy will flow from the region of high temperature to the region of low temperature.
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conductivity conductivity is the reciprocal of resistivity Project: GP40 NOTE: For water purification systems, conductivity is usually reported in microsiemens per centimeter (µS/cm).
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confidence interval an interval estimate of a population parameter computed so that the statement “the population parameter lies in this interval” will be true... in a stated proportion of the times such statements are made Project: ASTM08
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confidence interval the computed interval with a given probability (eg, 95%) that the true value of a variable, such as a mean, proportion, or rate, is contained within the interval Project: MM09, GP45, I/LA21, H57, MM17, EP35
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confidence interval calculated bounds that capture the true concentration or activity of the measurand in the sample with certain probability Project: EP19
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confidence level value (1 − α) of the probability associated with a confidence interval or a statistical coverage interval (ISO-19973-1) Project: MM17
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confidence level 1) the probability that the interval estimate contains the population parameter when the null hypothesis is true; 2) the probability the null hypothesis won’t be rejected when it is true Project: EP07 NOTE 1: The probability is usually denoted as a percentage: 100(1 − α)%; NOTE 2: See alpha error.
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confidence limit a number or pair of numbers that define a confidence interval Project: NRSCL08, MM17
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confidentiality the entrustment of information form one party to another for that party's exclusive use not imparted to others Source: Quality Glossary NOTE: "Confidentiality" is not synonymous with "privacy"
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confirmation test a procedure that is based on a different, more specific, physicochemical method than the original screening assay, and used to confirm positive screening test results; confirmation tests are typically quantitative Project: C52 NOTE: A confirmatory test determines whether a specimen is ultimately reported as positive or negative. Gas chromatography/mass spectrometry is generally used for forensic confirmatory testing.
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confirmatory assay a modification of the immunoglobulin E antibody assay in which drug or buffer (sham control) is first mixed with the test serum and the mixture is analyzed in the assay. Competitive inhibition of the immunoglobulin E antibody binding to the immobilized or labeled drug by solution phase drug confirms the specificity of the antibody for the drug. Due to the typically low levels of immunoglobulin E antibody in human serum, competitive inhibition may not be technically possible to achieve Project: I/LA34
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confirmatory test (for newborn screening) a test to prove or disprove the presence of a specific disease, group of diseases, or phenotypic difference suspected because of screening test results Alternate Term: diagnostic test Project: NBS03, NBS08, NBS09, NBS05, NBS02, NBS13, NBS10 Source: Newborn Screening Glossary NOTE: For newborn screening and identity confirmation, confirmatory testing must be performed on a new specimen, rather than on any existing screening specimen.
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confirmatory testing a second test that establishes the presence or absence of a measurand by a method with higher analytical sensitivity or specificity (or both) than the initial test; a procedure that is based on a different physicochemical method than an original screening assay and used to confirm positive screening test results Project: C63 NOTE 1: Confirmatory tests are typically quantitative; NOTE 2: A confirmatory test determines whether a specimen is ultimately reported as positive or negative. Gas chromatography–mass spectrometry or liquid chromatography–tandem mass spectrometry is generally used; NOTE 3: When the screening test is negative and a second more sensitive and specific technique is used, this subsequent test is considered a definitive method or targeted testing; NOTE 4: Related terms include confirmation test, definitive method, and targeted testing.
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confirmatory testing a test that establishes the presence or absence of a measurand by another method that is more sensitive, more specific, or both Project: MM09 NOTE: A test to confirm the presence or absence of a clinical condition as a follow-up to previous testing that indicated that the patient is at higher risk for a clinical condition.
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conflict of interest situation that has the potential to undermine the impartiality of an individual because of the possibility of differences between the individual’s self-interest and professional interest or public interest Project: QMS05 Source: Quality Glossary
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conformance fulfillment of a requirement Alternate Term: conformity Project: QMS01, QMS02 Source: Quality Glossary
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confounding 1) a situation in which the effects of two processes are not separated; 2) a situation in which the intervention effect is biased because of some difference between the comparison groups apart from the planned interventions, such as baseline characteristics, prognostic factors, or concomitant interventions Project: GP45 NOTE 1: The distortion of the apparent effect of an exposure on risk brought about by the association with other factors that can influence the outcome; NOTE 2: For a factor to be a confounder, it must differ between the comparison groups and predict the outcome of interest.
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congenital hypothyroidism thyroid hormone deficiency that is present at birth and that may be permanent or transient Project: NBS10 NOTE: See primary congenital hypothyroidism, central congenital hypothyroidism, subclinical congenital hypothyroidism, and transient congenital hypothyroidism.
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conidium (pl. conidia) an asexual reproductive structure that forms on the side or the end of a hypha or conidiophore Project: M54
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conjugate a covalent or noncovalent combination of a large molecule and another molecule Project: AST02 NOTE 1: For example, a compound formed by a label coupled with an antibody or antigen; NOTE 2: Conjugates of antibody with fluorochromes, radioactive isotopes, or enzymes are often used in immunoassays.
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conjugate a material produced by attaching two or more substances together NOTE: For example, a compound formed by a label coupled with an antibody or antigen.
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conjugate an assay reagent that is produced by covalently attaching two (or more) substances to each other such as an antibody with a second biolabel (enzyme [horseradish peroxidase, alkaline phosphatase] or biotin), radiolabel, colloidal gold particle, or fluorophor Project: I/LA34, I/LA20 NOTE: In the solid-phase, two-site immunometric assays that have been used historically in diagnostic allergy laboratories, the conjugate is commonly a labeled antihuman immunoglobulin E reagent. In some recent fluid-phase assays, the conjugate may be a biolabeled allergen reagent.
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connectivity the ability to reliably transfer test information between a point-of-care testing device and an information system Project: POCT01
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connectivity the ability to reliably transfer data between a point-of-care testing device and a computer system database Project: POCT02
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Connectivity Industry Consortium a group of more than 50 healthcare institutions, point-of-care diagnostic vendors, diagnostic test system vendors, and system integrators who formed a consortium in 2000 to address standards for point-of-care connectivity Project: POCT01 NOTE 1: The Connectivity Industry Consortium developed a standardization specification within its planned one-year lifetime, and then handed this specification over to CLSI (www.clsi.org), Health Level 7 (www.hl7.org), and IEEE (www.ieee.org) organizations for subsequent maintenance and extension; NOTE 2: The Connectivity Industry Consortium specification forms the basis for the CLSI POCT01 standard.
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consensus in CLSI documents, the substantial agreement by materially affected, competent, and interested parties that is obtained by following the procedures specified for CLSI consensus approval Project: NRSCL08, VET03 NOTE: CLSI consensus does not always connote unanimous agreement, but it does mean that the participants in the development of a standard or guideline have considered and resolved all relevant comments and are willing to abide by the resulting agreement.
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consensus sequence a conclusive sequence generated from an assembly or alignment of multiple individual sequences coding for the same gene region, where differences between the individual sequences at distinct positions are represented by ambiguity codes Project: MM18 NOTE: The consensus sequence represents the diversity between a number of individual sequences of interest.
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consensus sequence the final sequence generated from a compilation of overlapping sequences after base calling is complete at all positions Project: MM09 NOTE: The consensus sequence is believed to represent the source nucleic acid.
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consensus value for a reference material, the value of the quantity obtained by interlaboratory testing, or by agreement between appropriate bodies or experts (ISO Guide 30/92-3.3)
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conservation of a measurement standard set of operations necessary to preserve the metrological properties of a measurement standard within stated limits (JCGM 200:2012) Alternate Term: maintenance of a measurement standard Project: ISO IEC Guide 99 NOTE 1: Conservation commonly includes periodic verification of predefined metrological properties or calibration, storage under suitable conditions, and specified care in use (JCGM 200:2012); NOTE 2: The operations commonly include periodic calibration, storage under suitable conditions, and care in use.
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conserved gene a sequence of amino acids in a polypeptide or of nucleotides in DNA or RNA that is similar across multiple species, with very little diversity Alternate Term: conserved sequence Project: MM18 NOTE: A known set of conserved sequences can be represented by a consensus sequence.
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consistency the degree of uniformity, standardization, and freedom from contradiction among the documents or parts of a system or component (IEEE 610.12-1990) Project: AUTO08
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constant a number that expresses a property, quantity, or relation that remains unchanged under specified conditions Project: NRSCL08
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constant air volume air supply and exhaust system where the airflow always stays the same Project: QMS04
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construction sixth and last design phase of a construction project, in which the actual construction is occurring Project: QMS04 NOTE: The administration refers to the task of the architect in relation to construction.
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construction documents fourth design phase of a construction project, in which drawings and specifications, which tell the contractors exactly what to purchase and how they should be constructed, are prepared Project: QMS04 NOTE: In QMS04, “CD” refers to both the “construction documents” phase of laboratory design, and the physical documents associated with this phase. When the latter use is intended, the abbreviation may be pluralized as “CDs” if multiple documents are indicated.
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consultative services organized program supported by dedicated staff at a referral laboratory, designed to provide specific information to referring laboratory clients to facilitate the ordering and performance of examinations or the interpretation of examination results Project: QMS05 NOTE: A consultation may involve technical information or medical interpretive information.
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consumable materials materials that are used and then disposed, become incorporated into other materials and lose their identity, or cannot be used for their intended purpose without obliterating or transforming their substance Project: QMS21 Source: Quality Glossary EXAMPLES: Disposable pipettes, pipette tips, test tubes, instrument cuvettes; reagents and controls; label stock.
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contact (transmission) the spread of infectious agents through the direct transfer of microorganisms from one person to another or indirect transfer of microorganisms from a contaminated object or person Project: M29
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contact activator a substance that activates coagulation Factor XII to active proteolytic enzyme Project: H47 NOTE: These activators are normally negatively charged particulate substances but may be soluble compounds.
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contact activator a particulate (eg, kaolin, diatomaceous earth, silica) or soluble (eg, ellagic acid) substance that activates the “contact phase of coagulation,” involving Hageman factor (factor XII), prekallikrein (Fletcher factor), and high-molecular-weight kininogen, thereby initiating the intrinsic-phase blood coagulation pathway (ie, activation of factors XI and IX). Project: POCT14
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contact precautions applied to patients known or suspected to have serious illnesses easily transmitted by direct patient contact or by contact with items in the patient's environment
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contact transmission the spread of infectious agents through the direct transfer of microorganisms from one person to another or indirect transfer of microorganisms from a contaminated object or person
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contactor membrane a hydrophobic membrane used in removing dissolved gases from water Project: GP40
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container the receptacle that contains the specimen Project: H21
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container an object that holds a specimen from an individual patient Project: AUTO02, AUTO12, AUTO14
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container failure any situation that leads to the loss of the specimen or its alteration so as to render it unsatisfactory for analysis Project: M40
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container interior
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contaminant a microorganism, chemical, or other material that makes something impure by contact or mixture with it Project: M29, POL1/2
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contaminant a microorganism isolated from a blood culture that was introduced into the culture during specimen collection or processing and that was not pathogenic for the patient from whom blood was drawn (ie, the isolates were not present in the patient’s blood when the blood was drawn for culture) Project: M47
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contaminated presence or the reasonably anticipated presence of blood or other potentially infectious materials on an item or surface (29 CFR 1910.1030) Project: X03, M29
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contaminated sharps any contaminated object that can penetrate the skin including, but not limited to, needles, scalpels, broken glass, broken capillary tubes, and exposed ends of dental wires Project: X03
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contaminated sharps any contaminated object that may inflict a puncture or laceration of the skin including, but not limited to, needles, scalpels, broken glass, lancets, and broken capillary tubes Project: M29
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contamination the presence of an infectious or toxic agent or matter on a human or animal body surface, in or on a product prepared for consumption or on other inanimate objects, including conveyances that may constitute a public health risk Project: POCT16
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context of use complete and precise statement that describes appropriate use of the biomarker assay and how the validated assay is allowed to be used. The context of use statement is based on the endpoint to which the assay has been qualified or validated (ie, exploratory, secondary, or primary). During drug development and regulatory review, the context of use statement also describes important criteria regarding the circumstances under which the biomarker is qualified
Project: H62 NOTE: Context of use is central to biomarker qualification.
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contig from the word “contiguous”; a series of overlapping DNA sequences used to make a physical map that reconstructs the original DNA sequence of a chromosome, a region of chromosome, or an extrachromosomal element Project: M64 NOTE: A contig can also refer to one of the DNA sequences used in making a map.
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contingency plan a coordinated strategy that involves plans, procedures, and technical measures to enable the recovery of systems and continued operations after a disruption Project: HS11
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continual improvement recurring activity to enhance performance (ISO 9000) Project: QMS19, QMS06, EP23, MM20, QMS11, QMS01 Source: Quality Glossary NOTE 1: Also known as continuous improvement; NOTE 2: Continual improvement includes the actions taken throughout an organization to increase the effectiveness and efficiency of activities and processes to provide added benefits to the customer and organization; NOTE 3: Includes the actions taken throughout an organization to increase the effectiveness and efficiency of activities and processes to provide added benefits to the customer and organization; NOTE 4: The process of establishing objectives and finding opportunities for improvement is a continual process through the use of audit findings and audit conclusions, analysis of data, management reviews, or other means and generally leads to corrective (or preventive) action.
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continuing education formal lectures, courses, seminars, webinars, or any other similar type of educational program designed to educate an individual and give him or her further skills or knowledge to be applied in his or her line of work Project: QMS16, QMS03 NOTE: Training activities for an individual’s current job functions, tasks, and responsibilities are not considered continuing education.
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continuous glucose monitoring (CGM) a glucose monitoring system with a sensor that measures glucose levels at regular and frequent intervals (eg, every 15 minutes or less) over the wear period Project: POCT05
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continuous glucose monitoring lag time the interval required for a change in blood glucose concentration to cause a change in the measured glucose reading
Project: POCT05
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continuous monitoring for the purposes of ambulatory monitoring, a sensor is considered continuous if it provides a value at least every 15 minutes or more frequently
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contract review defined activities carried out before entering into a contract agreement to ensure that requirements are adequately defined and understood, and can be achieved (ISO 8402, 3.10)
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contractor a person who is hired through an agreement or other arrangement to perform a service or to provide goods at a certain price or within a certain period of time Project: QMS16 NOTE: A consultant is an example of a contractor.
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contrived sample a sample created to mimic a native sample NOTE: Commonly contrived samples are created by dilution or comixing of native samples or by adding or spiking measurand to native samples or to a manufactured sample with a matrix similar to native samples.
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control (ie, control material) a device, solution, lyophilized preparation, or panel of collected human or animal specimens, or artificially derived materials, intended for use in the quality control process Project: H47, H44, NRSCL08, MM10, MM12, VET03, C34, I/LA34, QMS23 NOTE 1: The expected reaction or concentration of analytes of interest are known within limits ascertained during preparation and confirmed in use; NOTE 2: Control materials should not be used for calibration in the same process in which they are used as controls; NOTE 3: The control serum should possess a matrix similar in ionic charge, density, pH, and protein content to that of the test specimens. It serves as the primary quality control check on the validity of the calibration-reference curve, the assay reagents, and any required equipment. Moreover, it allows computation of interassay variation using values obtained from more than 10 individual assay runs. A range of values (2 standard deviations, 95% confidence interval) are computed for the control specimen and should be used in Levey-Jennings quality control charts to identify assays that are in or out of control; NOTE 4: The control serum should theoretically possess a matrix similar to that of the test specimen (eg, with similarity in ionic charge, density, pH, and protein content). It serves as the primary quality control check on the validity of the calibration-reference curve, the assay reagents, and any required equipment.
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control the administration of an antimicrobial agent to an individual animal with a subclinical infection to reduce the risk of the infection becoming clinically apparent, spreading to other tissues or organs, or being transmitted to other individual animals Alternate Term: metaphylaxis Project: VET03, VET01, VET09 NOTE 1: On a population basis, control is the use of antimicrobial agents to reduce the incidence of infectious disease in a group of animals in which some individual animals already have evidence of infectious disease or evidence of infection; NOTE 2: Therapeutic use of antimicrobial drugs includes treatment, control (also known as metaphylaxis), and prevention (also known as prophylaxis); NOTE 3: See breakpoint, treatment, and prevention//prophylaxis.
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control to monitor the status of an analysis to maintain its performance within desired limits Project: MM10, POCT04
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control a standard sample included in an assay to assess the validity of the test. A control has a predicted outcome with an acceptable range of values Project: MM06
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control (plasma) a batch of citrated plasma used to monitor the stability of the laboratory test system, which includes reagents, instruments, reconstituting and diluting fluids, and pipettes Project: H30 NOTE 1: “Normal control plasma” gives test results within the range of the reference interval; NOTE 2: “Abnormal control plasmas” for factor assays should contain factor concentrations below the reference interval values due to abnormally low factor concentrations; NOTE 3: If factors are clinically elevated, the “abnormal control plasma” should contain factor concentrations above the reference interval; NOTE 4: Normal and abnormal control plasmas may be prepared in the laboratory or obtained commercially.
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control method or substance with known values used to monitor the status of a measurand to maintain its performance within desired limits Project: MM09, MM17
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control device, solution, lyophilized preparation, or panel of collected human or animal specimens or artificially derived materials intended for use in the quality control process Alternate Term: control material; quality control material Project: POCT14, MM22, MM01, H62 NOTE 1: The expected reaction or concentration of measurands (analytes) of interest are known within limits ascertained during preparation and confirmed in use; NOTE 2: Control materials are generally not used for calibration in the same process in which they are used as controls; NOTE 3: Substance, material, or article used to verify the performance characteristics of an in vitro diagnostic medical device; NOTE 4: In medical laboratories it should be similar to and is analyzed along with patient specimens. If different, it should have a recognized, defined response to analytical measurements; NOTE 5: Control materials may or may not have known measurand concentrations (ie, assigned values) within specified limits (eg, target value, standard deviation).
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control a device, solution, lyophilized preparation, or cellular element intended for use in the quality control process Project: I/LA28 NOTE 1: The expected reaction or concentration of analytes of interest are known within limits ascertained during preparation and confirmed in use; NOTE 2: Control materials are generally not used for calibration in the same process in which they are used as controls; NOTE 3: With regard to immunohistochemistry, controls are usually cells or tissues with known immunoreactivity or normal internal elements within the patient specimen with known immunoreactivity.
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control a device, material, solution, or lyophilized preparation intended for use in the quality control process Alternate Term: control material Project: NBS05, MM24, NBS10 NOTE 1: The expected reaction or concentration of analytes and/or measurands of interest are known within limits ascertained during preparation and confirmed in use; NOTE 2: Control materials are generally not used for calibration in the same process in which they are used as controls.
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control condition recipient reagent tested under normal operating conditions without any steps taken to deliberately increase the carryover effect Project: EP47 NOTE: The recipient reagent is used to establish the expected response in the absence of significant carryover.
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control interval statistically justified values specified as acceptable measured values obtained using a given control material (ISO 17593) Project: ISO 17593
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control limit the most extreme value of a quality control material that is still considered to be acceptable
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control material substance, material, or article intended by the manufacturer to be used to verify the performance characteristics of an in vitro diagnostic medical device (ISO 17593) Project: ISO CD 18112-1, ISO 15197, ISO 17593, ISO 18113-1, ISO 18113-2, ISO 18113-3 NOTE: Control materials for anticoagulation monitoring may be reactive or nonreactive. A reactive control material participates in a reaction with the reagent components. A nonreactive control does not react with the reagent components, but may provide control functionality through other means, eg, a simulation of the reaction (ISO 17593).
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control material a device, material, solution, or lyophilized preparation intended for use in the quality control process Project: H26, MM19, VET04 NOTE 1: It should be similar to, and is analyzed along with, patient specimens. If different, it should have a recognized, defined response to analytical measurements. Control materials may or may not have known measurand concentrations (ie, assigned values) within specified limits (eg, target value, standard deviation). Control materials are not used for calibration purposes; NOTE 2: The expected reaction or concentration of analytes of interest are known within limits ascertained during preparation and confirmed in use; NOTE 3: Control materials are generally not used for calibration in the same process in which they are used as controls.
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control material substance, material, or article used to verify the performance characteristics of an in vitro diagnostic medical device (ISO 15198) Project: ISO 15198
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control material substance, material, or article intended by its manufacturer to be used to verify the performance characteristics of an in vitro diagnostic medical device (ISO 15197) Project: ISO 15197, H26, QMS06
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control material a device, solution, or lyophilized preparation intended for use in the quality control process to monitor the reliability of a test system and to maintain its performance within established limits Alternate Term: control Project: POCT08, MM03, POCT04, POCT15 NOTE 1: The expected reaction or concentration of analytes of interest are known within limits ascertained during preparation and confirmed in use; NOTE 2: Control materials are generally not used for calibration in the same process in which they are used as controls; NOTE 3: Alternate terms include “procedural control,” “internal control,” “external control,” “onboard control,” and “built-in control.”
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control material a device, solution, lyophilized preparation, or panel of collected human or animal specimens, or artificially derived materials, intended for use in the quality control process Project: I/LA20 NOTE: The control serum should possess a matrix similar in ionic charge, density, pH, and protein content to that of the test specimens. It serves as the primary quality control check on the validity of the calibration-reference curve, the assay reagents, and any required equipment. Moreover, it allows computation of interassay variation using values obtained from more than 10 individual assay runs. A range of values (two standard deviations, 95% confidence interval) are computed for the control specimen and should be used in Levey-Jennings quality control charts to identify assays that are in or out of control as a result of observed shifts and trends.
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control material See control Project: I/LA28
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control measure action taken to reduce risk; action taken to reduce risk Project: EP18 NOTE 1: Some examples of the action are a policy, procedure or procedure change, and product or product change; NOTE 2: Also called “mitigation”; NOTE 3: Similar to a corrective action, but for an event that has not happened.
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control number See batch code and lot number Project: GP39
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control of infection plan set of procedures to be used to limit spread of infection in either a hospital or a laboratory (ISO 15190) Project: ISO 15190
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control plasma a preparation of fresh, frozen, or lyophilized plasma collected from human or animal blood, or artificially derived material, intended for use in the quality control process Project: H30, H51 NOTE 1: Control plasmas are used to monitor all aspects of the laboratory test system, including the reagents, instruments, reconstituting and diluting fluids, and pipettes; NOTE 2: Normal controls should give test results within the reference interval; NOTE 3: Abnormal control plasmas should give values within the clinically relevant abnormal range.
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control point a point, step, or procedure in a process at which a control can be applied and, as a result, a hazard can be prevented, eliminated, or reduced Project: EP23
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control procedure activities at the point of use to monitor the performance of an IVD medical device (ISO 15198) Project: ISO 15198 NOTE 1: In the IVD medical device industry and in many laboratories that use IVD medical devices, these activities are commonly referred to as quality control (ISO 15198); NOTE 2: Quality control may monitor all or part of the measurement procedure, from the collection of samples to reporting the result of the measurement (ISO 15198).
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control procedure set of operations at the point of use, described specifically, intended to monitor the performance characteristics of an IVD medical device and fulfill requirements for quality (ISO 18113-1) Project: ISO 18113-1, ISO 18113-2, ISO 18113-3 NOTE: Control procedures can be intended to monitor all or part of the IVD examination process, from the collection of the sample to reporting the result of the examination (ISO 18113-1).
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control procedure operational techniques and activities at the point of use to monitor the performance of an IVD medical device and fulfill requirements for quality (modified from ISO 15198) Alternate Term: quality control Project: ISO CD 18112-1 NOTE 1: In the IVD medical device industry and in many in vitro diagnostic laboratories, these activities are commonly referred to as quality control (ISO 15198); NOTE 2: The control procedure may monitor all or part of the measurement procedure, from the collection of sample to reporting the result of the measurement (ISO 15198); NOTE 3: In some laboratory quality systems, control procedures within the laboratory have been referred to as"internal quality control."
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control range interval of statistically justified acceptable values specified by the manufacturer for results obtained using the control material
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control tube any reference tube used as a comparative tube when evaluating a new or substantially modified tube Project: GP34 NOTE: In the United States, these tubes must be US Food and Drug Administration cleared.
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controlled copy an approved document that bears all appropriate document control markings such as identification and revision status Project: QMS02 NOTE: Controlled copies are distributed for use within the facility and are accounted for when revisions are made, to ensure that obsolete copies are removed from potential use.
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controlled room temperature a temperature maintained thermostatically that encompasses the usual and customary working environment of 20 to 25°C (68 to 77°F) that allows for brief deviations between 15 to 30°C (59 to 86°F) that are experienced in pharmacies, hospitals, and warehouses. For the purposes of this document, controlled room temperature is defined as 20 to 25°C (68 to 77°F), which should be monitored during test performance Project: M40
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controller See facilitator Alternate Term: facilitator Project: GP36
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convection the flow of heat through a bulk, macroscopic movement of matter from a hot region to a cool region Project: GP28
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conventional blood culture system a blood culture system that processes bottles without the use of mechanical systems (ie, manually) Alternate Term: manual blood culture system Project: M47
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conventional quantity value quantity value attributed by agreement to a quantity for a given purpose (JCGM 200:2012) Alternate Term: conventional value of a quantity; conventional value Project: ISO IEC Guide 99, EP29, EP15 EXAMPLE 1: Standard acceleration of free fall (formerly called "standard acceleration due to gravity"), gn = 9.806 65 m·s−2 (JCGM 200:2012); EXAMPLE 2: Conventional quantity value of the Josephson constant, KJ-90 = 483 597.9 GHz · V−1 (JCGM 200:2012); EXAMPLE 3: Conventional quantity value of a given mass standard, m = 100.003 47 g (JCGM 200:2012); NOTE 1: The term “conventional true quantity value” is sometimes used for this concept, but its use is discouraged (JCGM 200:2012); NOTE 2: Sometimes a conventional quantity value is an estimate of a true quantity value (JCGM 200:2012); NOTE 3: A conventional quantity value is generally accepted as being associated with a suitably small measurement uncertainty, which might be zero (JCGM 200:2012).
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conventional reference scale quantity-value scale defined by formal agreement (JCGM 200:2012) Project: ISO IEC Guide 99
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conventional smear a method of slide preparation where a sample of cells collected from the cervix/vagina is smeared and fixed onto a glass slide in the patient examination room Project: GP15
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conventional true value (of a quantity) value attributed to a particular quantity and accepted, sometimes by convention, as having an uncertainty appropriate for a given purpose; EXAMPLESa) at a given location, the value assigned to the quantity realized by a reference standard may be taken as a conventional true value;b) the CODATA (1986) recommended value for the Avogadro constant, NA : 6,022 136 7 x 1023 mol-1 NOTE 1: Conventional true value is sometimes called assigned value, best estimate of the value, conventional value, or reference value. Reference value, in this sense, should not be confused with reference value in the sense used in the NOTE to 5.7 in VIM93; NOTE 2: Frequently, a number of results of measurements of a quantity is used to establish a conventional true value.
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conventional true value a value attributed to a particular quantity and accepted, sometimes by convention, as having an uncertainty appropriate for a given purpose (VIM93-1.20) NOTE: It is sometimes called assigned value, best estimate of the value, conventional value, or reference value; frequently, a number of results of measurements of a quantity is used to establish a conventional true value (VIM93-1.20).
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conventional value See conventional quantity value Alternate Term: conventional quantity value; conventional value of a quantity Project: C51
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conventional value of a quantity See conventional quantity value Alternate Term: conventional quantity value; conventional value Project: C51
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conversion process of changing records from one medium to another or from one format to another while maintaining the record’s authenticity, integrity, reliability, and usability Project: QMS26
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conversion factor between units ratio of two measurement units for quantities of the same kind (JCGM 200:2012) Project: ISO IEC Guide 99 EXAMPLE 1: km/m = 1000 and thus 1 km = 1000 m (JCGM 200:2012); NOTE: The measurement units may belong to different systems of units (JCGM 200:2012); EXAMPLE 2: 1 h/s = 3600 and thus 1 h = 3600 s (JCGM 200:2012); EXAMPLE 3: (km/h)/(m/s) = (1/3.6) and thus 1 km/h = (1/3.6) m/s (JCGM 200:2012).
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cool temperature any temperature between 8 and 15°C (46 to 59°F) Project: M40
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coordinator person empowered by the manufacturer or investigator with responsibility for the entire performance evaluation (ISO 20776-2) Project: ISO 20776-2
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coordinator an individual who is responsible for oversight of activities related to a blood glucose monitoring program Project: POCT13
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CO-oximeter term commonly used for a multiwavelength photometer for measurement of hemoglobin concentration and relative amounts of oxy-, deoxy-, carboxy-, and methemoglobin components in blood. The process of measuring these species in blood using a multiwavelength photometer is commonly referred to as “CO-oximetry.” An older term, “hemoximetry,” initially referred to the measurement of the oxy- and deoxyhemoglobin species; but it can also include the measurement of carboxy- and methemoglobin, as well Project: C46
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copolymer a polymer formed from two or more different monomers Project: GP40
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copy (noun) an imitation or reproduction of an original; a duplicate; a file that has the same data as another file Project: QMS26
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copy (verb) to make a reproduction of an original Project: QMS26
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copy number variant an insertion or deletion that involves a DNA fragment of 1 kb or larger Project: MM09
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copy number variation the number of copies of a particular gene or chromosomal segment present in the genome of an individual, usually indicating insertions or deletions that involve a DNA fragment of one kb or larger Project: MM26 NOTE: In tumor studies, copy number variation needs to be distinguished from tumor-associated somatic amplifications and deletions.
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core biopsy a cylindrical section of tissue that has been removed for pathology analysis, often from a formalin-fixed, paraffin-embedded block Project: MM23
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correct detection rate percentage of occasions when the reference blood glucose level reached the alert setting and the continuous glucose monitoring system initiated an alert within a prespecified time window before or after the blood glucose reached the alert setting Project: POCT05
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corrected report a change in a previously issued examination report intended to correct an inaccuracy, including changes in examination results, patient identification, reference intervals, interpretation, or other content Project: QMS26 Source: Quality Glossary
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corrected report change made to remove or correct an error; generally, a corrected report derives from clerical or reporting errors and not from diagnostic errors Project: QMS12 EXAMPLE: Correcting a typographical error from 15 ng/mL to 45 ng/mL.
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corrected result result of a measurement after correction for systematic error
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correction compensation for an estimated systematic effect (JCGM 200:2012) Project: ISO IEC Guide 99 NOTE 1: See ISO/IEC Guide 98-3:2008, 3.2.3, for an explanation of ‘systematic effect’; NOTE 2: The compensation can take different forms,such as an addend or a factor, or can be deduced from a table (JCGM 200:2012).
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correction factor numerical factor by which the uncorrected result of a measurement is multiplied to compensate for systematic error (VIM93) NOTE: Since the systematic error cannot be known perfectly, the compensation cannot be complete.
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corrective action action(s) to eliminate the cause and prevent recurrence of a nonconformity or other undesirable situation (ISO 9001) Project: QMS06, QMS11, QMS13, QMS17, QMS19, QMS24, QMS01 Source: Quality Glossary NOTE: There can be more than one cause for a nonconformity or undesirable situation.
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corrective action action to eliminate the cause of a nonconformity and to prevent recurrence (ISO 9000) Project: EP18, POCT09, POCT07, GP23 NOTE 1: There can be more than one cause for a nonconformity (ISO 9000); NOTE 2: Corrective action is taken to prevent recurrence, whereas preventive action is taken to prevent occurrence (ISO 9000); NOTE 3: Some examples of the action are a policy, procedure or procedure change, and product or product change; NOTE 4: Similar to a corrective action, but for an event that has not happened; NOTE 5: There is a distinction between correction and corrective action; a correction removes a nonconformity, whereas a corrective action removes the cause of the nonconformity (ISO 9000).
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correctness 1) the degree to which software is free from faults in its specification, design, and coding; 2) the degree to which software, documentation, and other items meet specified requirements; 3) the degree to which software, documentation, and other items meet user needs and expectations, whether specified or not (IEEE 610.12-1990) Project: AUTO08
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correlation 1) the relationship between two, or several, random variables within a distribution of two or more random variables (ISO 3534-1/93-1.13); 2) the comparison of results between the test (new) measurement procedure and the reference (old) measurement procedure Project: ISO 3534-1, H26, POCT04 NOTE: High method correlation does not imply high numeric agreement of analytical results but only the predictability of one method’s results by the other method. As Westgard notes, “the fact that the correlation coefficient is commonly calculated doesn’t make it useful,” which simply means that r = 1 alone does not imply that test and comparative methods give the same result.
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correlation the degree to which two variables are proportionally related to each other NOTE: High method correlation does not imply high numeric agreement of analytic results, but only the predictability of one method’s results by the other method.
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correlation coefficient mean of the product of two standardized random variables in their joint probability distribution (ISO 3534-1) NOTE 1: The value of “r” will always be between -1 and +1; NOTE 2: When r = 1, there exists an exact linear relationship (ISO 3534-1/93-2.41); NOTE 3: “r” is frequently used as a numerical expression for the linear dependence between X and Y in the series of paired observations.
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correlation coefficient (r) a measure of the linear relationship between two random variables Alternate Term: determination coefficient Project: EP09 NOTE 1: It ranges from −1 to 1, ie, from perfect negative to perfect positive linear relationship; NOTE 2: r = 0 indicates no observed linear relationship.
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correlative biomarker biomarker that provides proof of mechanism or mechanism of action information but that is not used for medical decision-making in patients who provide the samples Project: MM23
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corrosive a substance that can cause damage to human skin at the site of contact Project: QMS04
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corrosive causing visible destruction of tissue at the site of contact (U.S. 40 CFR 261.22) NOTE: For solid waste, this term applies to any aqueous material that is highly acidic (pH < 2.0) or highly alkaline (pH > 12.5) (US 40 CFR 261.22).
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corrosive having the quality of corroding or eating away; erosive (RHUD1.7CD)
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corrosive any substance that causes visible destruction of human tissue at the site of contact Project: GP05 NOTE: The Environmental Protection Agency defines corrosivity as a substance that is highly acidic (pH ≤ 2.0) or highly alkaline (pH ≥ 12.5).
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cost expenses incurred in the provision of services or goods Project: GP45, GP49 NOTE 1: Many different kinds of costs are defined and used (see allowable, direct, indirect, and operating costs); NOTE 2: The price of a service or amount billed to an individual or third party may or may not be equal or proportional to service costs.
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cost of poor quality the costs associated with providing poor-quality products or services and rectifying the outcomes Project: QMS20
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cost of quality overall concept that includes understanding quality cost types, applying them to the laboratory’s or organization’s budget, and communicating the resulting quality cost information to improve the use of resources Project: QMS20
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cost per patient test the net of any cost associated with consumables, quality control, and calibrators, and includes labor costs; it includes dilution, repeat, and confirmatory testing Project: POCT09 NOTE: The cost per reportable patient test is higher than the cost per test. If the 100 test kit costs $1000 and 30 tests are used for quality control and calibration, then the reportable test is $1000/70 patients + labor costs and other consumables.
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cost-benefit analysis an analytic method in which a program’s cost is compared to the program’s benefits for a period of time, expressed in dollars, as an aid in determining the best investment of resources Project: GP45 NOTE 1: For example, the cost of establishing an immunization service might be compared with the total cost of medical care and lost productivity that will be eliminated as a result of more persons being immunized; NOTE 2: Cost-benefit analysis can also be applied to specific medical tests and treatments.
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cost-effectiveness analysis 1) This form of analysis seeks to determine the costs and effectiveness of an activity or to compare similar alternative activities to determine the relative degree to which they will obtain the desired objectives or outcomes; the preferred action or alternative is one that requires the least cost to produce a given level of effectiveness, or provides the greatest effectiveness for a given level of cost; 2) a form of analysis that seeks to determine the costs and effectiveness of a medical intervention compared to similar alternative interventions to determine the relative degree to which they will obtain the desired health outcome(s) Project: GP45 NOTE 1: In the healthcare field, outcomes are measured in terms of health status; NOTE 2: Cost-effectiveness analysis can be applied to any of a number of standards, such as median life expectancy or quality of life following an intervention.
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counting beads fluorescent microspheres of known concentration, which are combined in a known amount with a sample in order to assess the concentration of a population in that sample (eg, lymphocyte subsets, CD34+ hematopoietic stem cells) Project: H42
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courier service provider that facilitates the transport of specimens from a referring laboratory to a referral laboratory Project: QMS05 NOTE: A courier service may be provided by the referral laboratory or may be offered through a third party as part of a separate fee-for-service or contractual arrangement between the referring laboratory and referral laboratory.
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covariance mean of the product of two centred random variables in their joint probability distribution (ISO 3534-1) Project: ISO 3534
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covariance the covariance of two random variables is a measure of their mutual dependence (JCGM 100:2008 § C3.4) Project: C51 NOTE: The covariance between two random variables x and y can be symbolized sxy or cov(x,y).
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coverage the amount of sequencing data that is available per position in the sequenced genome territory Alternate Term: read depth Project: MM09 NOTE 1: “Coverage” is a collective term for a target region after alignment; NOTE 2: “Read depth” is an individual term at each nucleotide position.
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coverage factor number larger than one by which a combined standard measurement uncertainty is multiplied to obtain an expanded measurement uncertainty (JCGM 200:2012) Project: ISO IEC Guide 99, C51, EP30, EP32 NOTE 1: A coverage factor is usually symbolized k (JCGM 200:2012); NOTE 2: For standard uncertainties, the coverage factor is 1.
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coverage interval interval containing the set of true quantity values of a measurand with a stated probability, based on the information available (JCGM 200:2012) Project: ISO IEC Guide 99, C51 NOTE 1: A coverage interval does not need to be centered on the chosen measured quantity value (see ISO/IEC Guide 98-3:2008/Suppl.1) (JCGM 200:2012); NOTE 2: A coverage interval should not be termed "confidence interval" to avoid confusion with the statistical concept (see ISO/IEC Guide 98-3:2008, 6.2.2) (JCGM 200:2012); NOTE 3: A coverage interval can be derived from an expanded measurement uncertainty (see ISO/IEC Guide 98-3:2008, 2.3.5) (JCGM 200:2012).
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coverage probability probability that the set of true quantity values of a measurand is contained within a specified coverage interval (JCGM 200:2012) Project: ISO IEC Guide 99, C51 NOTE 1: This definition pertains to the Uncertainty Approach as presented in the GUM (JCGM 200:2012); NOTE 2: The coverage probability is also termed "level of confidence" in the GUM (JCGM 200:2012).
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coverage threshold in next-generation sequencing, the number of reads at which increased coverage is unlikely to improve sequencing data quality Project: MM09 NOTE 1: Generally refers to a specifically defined level of coverage or the number of times a region is resequenced under stated assay conditions; NOTE 2: The coverage threshold is generally the minimum coverage needed to yield valid or reliable results.
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covert incident an event intrinsically unrecognizable as life threatening at inception NOTE: For example, an infectious bioterrorist attack is usually covert, thus denying the exposed population prophylaxis.
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covert incident event that is not readily detectable or announced Project: GP36 EXAMPLE: An infectious bioterrorist attack is usually covert, thus denying prophylaxis to the exposed population; NOTE: A covert incident is classically represented by the dispersal or spread of an infectious agent. It can also pertain to the dispersal of a chemical or radiological agent. Victims occur over time, potentially at many geographically disparate sites. Early incident detection and epidemiology is difficult.
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CQI interface the important interchange of information between all five functionally interrelated CQI components of quality planning, quality teamwork, quality monitoring, quality improvement, and quality review NOTE: By utilizing the quality review component of the QSE: Organization, this interface facilitates the synchronization of all five CQI components.
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critical (services or processes) operations essential to the integrity of the quality management system and to patient care
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critical concentration for each drug, the critical concentration is the lowest concentration that inhibits 95% of wild-type strains of Mycobacterium tuberculosis complex that have not been exposed to the drug but that simultaneously does not inhibit strains of Mycobacterium tuberculosis complex considered resistant that are isolated from patients who are not responding to therapy Project: M24 NOTE 1: The “critical concentrations” of antituberculous drugs were adopted by international convention (JCGM 200:2012); NOTE 2: In 2018, the World Health Organization defined the critical concentration as the lowest concentration of an antituberculous agent in vitro that will inhibit the growth of 99% of phenotypically wild-type strains of Mycobacterium tuberculosis complex (WHO technical report 2018).
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critical congenital heart disease a group of heart defects that cause serious, life-threatening symptoms and need intervention within the first days or first year of life Project: NBS03
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critical control point a point, step, or procedure at which controls can be applied and a hazard or risk can be prevented, eliminated, or reduced to acceptable (critical) levels Project: I/LA33 NOTE: If the critical control point is omitted or not performed adequately, the process may be adversely affected. A function or an area in a manufacturing process or procedure that failure or loss of control may have an adverse effect on the quality of the finished product and may result in a health risk.
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critical control point a point or step in an analytical procedure that is susceptible to an error Project: POCT07 NOTE: With the implementation of the right quality control, an error can be mitigated to an acceptable level.
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critical control points (CCPs) groupings of related activities and tasks that must be accomplished effectively to minimize errors in operational processes
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critical difference the average difference between reported results from a set of patient samples that corresponds to the limit a laboratory is willing to accept Project: EP26
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critical equipment a piece of equipment, material, service, or task that can affect the quality of the facility’s products or services Alternate Term: critical materials; critical tasks Project: I/LA33
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critical failure a failure that can initiate a hazard Project: POCT07
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critical incident stress management (CISM) a product of the International Critical Incident Stress Foundation, Inc NOTE: ICISF is a nonprofit, open membership foundation dedicated to the prevention and mitigation of disabling stress through the provision of: education, training, and support services for all Emergency Services professions, which also provides consultation in the establishment of Crisis and Disaster Response Programs for varied organizations and communities worldwide. Information is available via: www.icisf.org.
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critical limit a criterion that separates acceptability from unacceptability Project: POCT07
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critical point a step in the operation of software that is essential to the quality of the function or task Project: AUTO13 NOTE: A critical point can influence the behavior of the system’s user or be a system-performed calculation, interpretation, or algorithm.
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critical reagents reagents without which the laboratory could not function or report results Project: QMS21
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critical risk result a category of quantitative, semiquantitative, or qualitative results of laboratory or anatomic pathology examinations that signify immediate risk of major adverse outcomes. These results need to be actively communicated to responsible caregivers without delay in order to ensure urgent clinical evaluation and medical intervention Project: POCT04
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criticality relative measure of the consequences of a failure mode and its frequency of occurrences Project: EP18 NOTE: Combining the consequences (severity) with frequency (probability) gives the same measure as defined in risk.
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criticality analysis procedure by which each potential failure mode is ranked according to the combined influence of severity and probability of occurrence (MIL-STD-1629A. Procedures for Performing a Failure Mode, Effects and Criticality Analysis. 24 November 1980.)
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critical-risk results a category of quantitative, semiquantitative, or qualitative results of laboratory or anatomic pathology examinations that signify immediate risk of major adverse outcomes. These results need to be actively communicated to responsible health care providers without delay to ensure urgent clinical evaluation and medical intervention Project: EP23, AUTO15
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cross-contamination physical or chemical movement or transfer of materials from one component of an examination procedure to another occurring as a random event Project: EP47
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crossed in the design of a multifactor study, the effects of a factor A are said to be crossed with the effects of a factor B if some of the effects of factor A occur with more than one effect of factor B Project: EP05 EXAMPLE: If the reagent lots that are studied at each of several sites are common across the sites, then reagent lot is crossed with site. Factors A and B are fully crossed if every effect of factor A occurs with every effect of factor B. See also nested.
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Cross-Enterprise Document Sharing provides a standards-based specification for managing the sharing of documents between any health care enterprise, ranging from a private physician office to a clinic to an acute care inpatient facility Project: AUTO16 NOTE: This is managed through federated document repositories and a document registry to create a longitudinal record of information about a patient within a given clinical affinity domain. These are distinct entities with separate responsibilities.
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cross-hybridization the hybridization of a probe(s) to more than one chromosomal locus NOTE 1: Some probes consistently cross-hybridize with multiple loci because of similar DNA sequences; other probes may cross-hybridize when the hybridization stringencies are not perfect; NOTE 2: Background signals are not cross-hybridized because they are rare, associate with random chromosomal sites, and often do not touch a chromosomal site.
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crossover testing the parallel testing performed on new and existing reagent systems or reagent shipments/lots to define their relationship and determine their acceptability Project: POCT04 Inter-measurement procedure (between-measurement procedure) - the difference between the results obtained by two specified measurement procedures. Of a result - the difference between the result and the true or expected value. Of an analytical process - the average difference between the results obtained by the analytical process in question under specified conditions of matrix, analyte concentration, etc., and the true or accepted result; synonym for “systematic error.”
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cross-reactive immunological material as used in NBS07, the presence in patients with Pompe disease of a mutant acid α-glucosidase protein that cross-reacts with antibodies against normal acid α-glucosidase enzyme Project: NBS07
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cross-reactivity in Immunology, the reaction of an antibody with an antigen other than that which elicited its formation, as a result of shared, similar, or identical antigenic determinants Project: LA01, DI01, ILA18, I/LA23, I/LA28, I/LA34, I/LA20 NOTE: Within the context of this document, cross-reactivity has two meanings. First, it refers to a human immunoglobulin E antibody that binds to an allergenic epitope that is structurally similar to, but not identical with, the molecule that elicited its formation. Cross-reactivity results from shared, similar, or identical allergenic determinants. There are many illustrations of cross-reactive allergen molecules—for example, among the Hymenoptera (vespid) venoms (see allergen section below). Second, cross-reactivity can refer to the degree to which the monoclonal or polyclonal antihuman immunoglobulin E detection reagents bind to other human immunoglobulin isotypes (immunoglobulin G, immunoglobulin A, immunoglobulin M, immunoglobulin D).
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cross-reactivity ability of a drug, metabolite, a structurally similar compound other than the primary measurand, or even an unrelated compound, to affect the measurement procedure Project: C52, C63, H62 NOTE 1: See specificity and selectivity; NOTE 2: In immunology, a systematic error in an immunoassay resulting in immunogenic recognition of substance different from the intended measurand, producing an analytical interference.
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cross-sectional study a type of observational study that examines the relationship between diseases or other health-related characteristics, and other variables of interest as they exist in a defined population at one particular time Project: GP45 NOTE 1: The presence or absence of disease and the presence or absence of the other variables (or, if they are quantitative, their level) are determined in each member of the study population or in a representative sample at one particular time; NOTE 2: The relationship between a variable and the disease can be examined: (1) in terms of the prevalence of disease in different population subgroups defined according to the presence or absence (or level) of the variables; and (2) in terms of the presence or absence (or level) of the variables in the diseased versus the nondiseased; NOTE 3: Disease prevalence rather than incidence is normally recorded in a cross-sectional study; NOTE 4: The temporal sequence of cause and effect cannot necessarily be determined in a cross-sectional study.
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cross-validation in statistics, the practice of partitioning a sample of data into subsamples, such that analysis is initially performed on a single subsample, while further subsamples are retained “blind” for subsequent use in confirming and validating the initial analysis
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cryoglobulin a mixture of globulins that precipitates when cooled and dissolves when reheated to body temperature Project: I/LA30
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cryopreservative a liquid, usually tryptic soy broth with glycerol or skim milk, used to preserve an organism during fast freezing Project: M50
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Cryoquick any material used to embed tissue for frozen sections Project: MM02
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cryptic epitope an antibody binding site that is hidden from the antibody due to the folding of the protein molecule Project: ILA29
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cryptology the science that includes both cryptography and cryptanalysis, and sometimes is said to include steganography (RFC 2828) Project: AUTO09
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C-terminal crosslinking telopeptide of Type I collagen peptides that are formed during collagen degradation, originating from the C-terminal telopeptide of collagen molecules Project: C48
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culture 1) the intentional growing of microorganisms, such as bacteria or fungi, in a controlled environment, for purposes of identification or other scientific study or for commercial and/or medicinal use; 2) the product resulting from the intentional growth of microorganisms Project: M47, M24
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culture the intentional growing of microorganisms (such as bacteria or viruses) or tissues, in a controlled environment, for purposes of identification or other scientific study, or for commercial and/or medicinal use
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culture the set of shared attitudes, values, goals, and practices that characterizes an institution or organization Project: QMS16
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culture the result of a process by which organisms are intentionally propagated. This includes typical clinical laboratory microorganisms grown in broth, on solid media, or in cell culture Project: M29 NOTE: Typical clinical cultures may be classified as either Category A or Category B, depending on the organism concerned and the professional judgment of the shipper.
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culture medium a substance or preparation used for the cultivation and growth of microorganisms Project: M47
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culture medium a substance or preparation used for the cultivation and growth of microorganisms or tissue Project: M24
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cumulative antimicrobial susceptibility test data report the report generated by analysis of antimicrobial susceptibility test results from a defined period of time that reflects the percentage of isolates of a given species or organism group that is susceptible to each of the antimicrobial agents tested; includes antibiograms and other relevant analyses presented in tabular, graphic, or other types of formats Project: M39
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cumulative distribution for any probability distribution, the cumulative distribution represents the set of each ordered value of the variable with its corresponding percentile
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cumulative frequency the number of members of a set of observations having values that are less than or equal to a given value
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customer all components of a health care organization where the in vitro diagnostic device is installed Project: AUTO09
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customer person or organization that could or does receive a product or a service that is intended for or required by this person or organization (ISO 9000) Project: QMS16, QMS19, QMS21, QMS06, QMS01 Source: Quality Glossary EXAMPLES: Consumer, client, end user, retailer, receiver of product or service from an internal process, beneficiary, and purchaser (modified from ISO 9000); NOTE 1: A customer can be internal or external to the organization (ISO 9000); NOTE 2: Employees may be regarded as internal customers; NOTE 3: A customer can be internal or external to the organization and can include patients and health care providers, eg, physicians, nurses, laboratory staff.
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customer organization or person that receives a product or service (modified from ISO 9000) Project: POCT07 EXAMPLES: Consumer, client, end user, retailer, beneficiary, purchaser, patient, or health care provider (modified from ISO 9000); NOTE 1: A customer can be internal or external to the organization (ISO 9000); NOTE 2: Employees may be regarded as internal customers; NOTE 3: Staff may be regarded as internal customers; NOTE 4: For the purposes of QMS01, customers can include patients and health care providers, eg, physicians, nurses, staff; NOTE 5: For point-of-care testing, the patient would be considered a customer, and the doctor, point-of-care operator, and so on may be regarded as internal customers (modified from ISO 9000).
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customer-supplier concept every internal and external customer is simultaneously receiving and supplying some service or product to or from other individuals in the system NOTE: The patient is the ultimate external customer-supplier; the laboratory employee is the primary internal customer-supplier.
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cutoff for a binary examination, the internal continuous response threshold above which the result is reported as positive and below which the result is reported as negative Project: EP12, MM07, EP12-IG NOTE 1: Competitive examinations behave in the opposite way, with results at lower response values than the cutoff reported as positive; NOTE 2: The cutoff is set during examination development; clinical performance cannot be evaluated until after the cutoff has been set; NOTE 3: Some binary examinations may have an equivocal zone for which the result is indeterminate. See equivocal zone.
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cutoff level See decision level Alternate Term: decision level; decision threshold; decision point Project: EP24
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cutoff value the quantitative value of a measurand that is used to decide whether the result is considered above or below a clinical or analytical decision point (usually positive or negative) Project: I/LA23, C63
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cutoff value quantitative value of the measurand that is used as the decision point between a positive and a negative result Project: MM17
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cutoff value minimal inhibitory concentration (MIC) value that separates bacterial populations based on a specific parameter Project: VET02 NOTE: Three cutoff values, clinical cutoff (COCL), pharmacodynamic cutoff (COPD), and wild-type cutoff (COWT), are generally used for breakpoint and interpretive category decision-making. - COCL – the MIC cutoff value selected by clinical and/or microbiological outcome vs MIC from prospective clinical studies.
- COPD – the MIC cutoff value derived using pharmacokinetic-pharmacodynamic indices; NOTE: COPD is established solely on the basis of the relationship between physiological free-drug exposures (eg, in blood, epithelial lining fluid, or possibly urine or milk) and the microbial susceptibility parameter (ie, MIC values).
- COWT – the MIC cutoff value that separates wild-type from non-wild-type bacterial populations on the basis of MIC distributions; NOTE 1: COWT is based on the MIC data associated with the epidemiological database derived from geographically diverse diagnostic laboratory surveys, which could include isolates derived from animals that were part of a clinical field trial; NOTE 2: See epidemiological cutoff value (ECV), which shares the same definition as COWT, ie, defining the highest MIC or smallest zone diameter for the wild-type population of isolates; however, in VET02, because clinical breakpoints are being defined by three cutoff values, COWT is used rather than ECV.
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cutoff value the quantitative value of an analyte (eg, the upper limit of a reference interval for a particular analyte) that is used to decide whether the result is above or below a clinical or analytical decision point (ie, usually positive or negative, but may also represent divisions between grades of positivity [eg, weak positive, moderate positive, strong positive]) Project: H60
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cut-point the response level in the assay that discriminates between the absence and presence of immunoglobulin E antibody (eg, negative and positive cut-points) Project: I/LA34 NOTE 1: They can be referenced to response reference intervals obtained in the assay using a panel of specimens from a known healthy (nondiseased) population and a known diseased population. Data normalization and outlier removal are issues discussed in the guideline; NOTE 2: See detection limit.
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cyanmethemoglobin hemoglobin in which the iron atoms are in the ferric state and which are bonded with cyanide ions Alternate Term: CNMetHb, hemiglobincyanide, HiCN (methemoglobin cyanide, cyanferrihemoglobin) Project: H15
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cyanobacterium-like body organism thought to be a new pathogen, possibly an oocyst, a flagellate, an unsporulated coccidian, a large Cryptosporidium spp., or a blue green alga and now thought to be coccidia in the genus Cyclospora (Cyclospora cayetanensis) Alternate Term: coccidian-like body Project: M28
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cycle threshold number of cycles needed for an amplicon to become detectable above background Project: MM16, MM17 NOTE 1: The cycle threshold value of each real-time polymerase chain reaction depends on the initial template amount (copy number) of the target sequence, and it is inversely proportional to the log of this copy number; NOTE 2: In an experiment in which all polymerase chain reactions have similar efficiency, the cycle threshold value will be the lowest for reactions in which the initial template copy number was highest.
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cycle time components the identified time segments of the process of moving from one sample to the next, including: presentation of specimen along transportation system to docking site at instrument; identification/recognition that the correct specimen is in place; either direct aspiration from specimen container by probe, or transfer of specimen container to instrument, aspiration, and return of specimen container to specimen carrier/transportation system; departure of completed specimen container; movement into position of next specimen container Project: AUTO01, AUTO02
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cyst the nonfeeding encysted stage of the protozoa Project: M28
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cystic fibrosis hereditary disease prevalent especially in Caucasian populations that appears usually in early childhood, which is inherited as an autosomal recessive monogenic trait and involves functional disorder of the exocrine glands; is marked especially by faulty digestion due to a deficiency of pancreatic enzymes, by difficulty in breathing due to mucus accumulation in airways, and by excessive loss of salt in the sweat Alternate Term: CF
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cystic fibrosis an inherited chronic disease primarily affecting the lungs and digestive systems; it is due to a defective cystic fibrosis transmembrane conductance regulator (CFTR) gene and its CFTR protein product Project: NBS05 NOTE: Present in about 30 000 people in the United States and 70 000 worldwide.
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cystic fibrosis carrier as used in NBS05, a heterozygote with a variant in one cystic fibrosis transmembrane conductance regulator (CFTR) allele and one normal or wild-type CFTR allele, such as an infant who had one CFTR variant identified through immunoreactive trypsinogen/DNA screening and then a negative sweat chloride test
Project: NBS05 NOTE: Infants who are cystic fibrosis carriers appear to be free of any signs or symptoms of cystic fibrosis disease, although a small percentage are identified by newborn screening because of a tendency to have increased immunoreactive trypsinogen concentrations.
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cystic fibrosis membrane conductance regulator a 1480 amino acid protein coded for by a gene located on the long arm of chromosome 7 (q31.2), which is a member of the ABC transporter protein family and acts as a chloride ion channel on the apical surface of secretory epithelial cells Project: NBS05
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cystic fibrosis membrane conductance regulator–related disorders clinical condition, usually presenting a monosymptomatic disorder in children or adults, that does not meet the diagnostic criteria of cystic fibrosis, but in which there is evidence of CFTR dysfunction
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cystic fibrosis–causing mutation a DNA sequence alteration causing cystic fibrosis, if in trans with another cystic fibrosis–causing mutation
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cystic fibrosis-causing variant a DNA sequence alteration causing cystic fibrosis, if in trans with another cystic fibrosis–causing variant Project: NBS05
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cytokine flow cytometry (CFC) a laboratory technique in which the following steps are performed: 1) cells are stimulated to produce cytokines in the presence of protein secretion inhibitors, permitting cytokines to accumulate inside the producing cells; 2) the cells are stained with antibodies for markers on their surface (e.g., anti-CD3, anti-CD4, or anti-CD8), washed, and fixed; 3) the cells are permeabilized, and then stained with the anticytokine antibody, followed by a wash step; and 4) the cells are then analyzed by flow cytometry NOTE: This term is synonymous with both intracellular cytokine staining (ICC) and intracellular cytokine flow cytometry (ICFC).
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cytomegalovirus most often, use of the term cytomegalovirus is meant to indicate human cytomegalovirus, a member of the herpes virus family Herpesviridae Project: I/LA26 NOTE 1: The term “HCMV” is sometimes encountered; NOTE 2: Many mammalian species have their own distinct cytomegaloviruses.
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cytomorphology the subcellular features of a cell Project: I/LA28 NOTE: As used in immunohistochemistry, it is the subcellular localization of the antibody-antigen reaction.
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cytopathic effect a variety of morphologic changes occurring in monolayered cell cultures as a result of viral infection Project: M41
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cytotoxicity assays a test based on complement-dependent cytotoxicity Project: ILA29 NOTE: When antibody is bound to antigen, complement is activated. The end result of the complement cascade is the membrane attack complex, which disrupts the cell membrane and destroys the cells. The detection of cell death correlates with the presence of specific antibody for the target antigen.
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dalton see unified atomic mass unit Project: C50
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dangerous goods materials which, when not properly handled and contained, can pose a risk to the health, safety, property, or environment and are included on the list of dangerous goods in the International Air Transport Association Dangerous Goods Regulations Project: M29
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data facts used as a basis for reasoning, discussion, or calculation Project: QMS12, QMS26, QMS01 Source: Quality Glossary
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data (continuous) data that can take an infinite number of values (as in categories) Project: I/LA28 EXAMPLES: Age, height, weight, pulse, and many analytes measured by enzyme-linked immunosorbent assay–type methods; NOTE 1: The data are measured on a continuous scale, with each unit equidistant from the next; NOTE 2: The analytical results from immunohistochemistry assays using formalin-fixed, paraffin-embedded specimens with detection systems using immunoenzyme-based detection systems are not expressed as continuous data.
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data (categorical) data that are not pure measurements but are in the form of labels assigned, such as “male” and “female” Project: I/LA28 NOTE: In immunohistochemistry assays, a categorical result might be expressed as positive or negative (for the presence or absence of a biomarker).
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data (semiquantitative) a test that has a dose-response that may be included in the reported result, but for which no authoritative calibration scale exists to determine the inaccuracy and imprecision Project: I/LA28 NOTE: This definition includes tests with subjective readout of quantification such as immunofluorescent–antinuclear antibody titers, and it includes tests with an instrumental readout of quantification such as ELISA–antinuclear antibody, in which the instrument scale cannot be referenced to an authoritative calibration scale. Tests that yield results in an approximate range of values (eg, trace, moderate).
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data (ordinal) data that are simply ordinal numbers Project: I/LA28 NOTE 1: Ordinal scales are frequently used in the grading and scoring systems used in immunohistochemistry, such as 0, 1, 2, 3+. The distance between the ordinal numbers may be traceable to independent quantitative assays, but the distances between the ordinal numbers or symbols are not constant mathematical relationships. For example, 1+ and 2+ do not equal 3+. 3+ minus 1+ does not equal 2+; NOTE 2: Ordinal data are also referred to as semiquantitative data.
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data acquisition board a device that collects and measures signals from sensors and sends them to a computer for processing Project: C39
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data availability the ratio of the number of available glucose readings to the number of expected glucose readings, usually given as a percentage Project: POCT05
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data confidentiality the property that information is not made available or disclosed to unauthorized individuals, entities, or processes (ie, to any unauthorized system entity) (RFC 2828; ISO/IEC 7498-1, 7498-2, 7498-4) Project: AUTO09
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Data Encryption Standard a US government standard that specifies the Data Encryption Algorithm and states policy for using the algorithm to protect unclassified, sensitive data (See Advanced Encryption Standard) (RFC 2828) Project: AUTO09
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data integrity the property that data has not been changed, destroyed, or lost in an unauthorized or accidental manner (RFC 2828) Project: AUTO09
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data manager typically, a manufacturer-specific network server or more general computer system that acts as an observation reviewer to provide collection of point-of-care data and storage of data, and communication of data, quality assurance/quality control, and other point-of-care instrument and data management functions Alternate Term: DM Project: POCT02 NOTE: In addition to these functions, data managers usually provide other applications or services tailored to specific devices or point-of-care user needs (such as management of operators, reagent lot numbers/expiration dates, and reports for regulatory compliance).
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data manager typically, a network server that provides the services of an observation reviewer (eg, point-of-care data storage and forwarding, quality assurance/quality control, and other point-of-care instrument and data management functions) Project: POCT01 NOTE 1: In addition to these services, data managers usually provide other applications or services tailored to particular devices or point-of-care user needs (such as regulatory reporting and operator management applications); NOTE 2: Data manager systems are specific instances of observation reviewer services.
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data manager interface specifies the Transmission Control Protocol/Internet Protocol network interface and protocol between a data manager and one or more access points Project: POCT01
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Data Matrix a type of two-dimensional bar code symbology, specifically Data Matrix ECC 200 (and not older, obsolete versions of Data Matrix), that is selected for use by CLSI AUTO14 Project: AUTO14 NOTE: Data Matrix bar codes may be in one of two formats: square and rectangular. See details in CLSI AUTO14 Chapters 5 and 6.
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data privacy assurance that the confidentiality of, and access to, certain information about an entity is protected Project: AUTO11
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data reduction algorithm a mathematical process that converts assay-response data (eg, counts per minute−bound, absorbance, fluorescence, chemiluminescence, or surface Plasmon resonance units) into interpolated dose results Project: I/LA20 NOTE: The dose-response relationship in the assay is defined by the standard, reference, or calibration curve.
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datum error measurement error of a measuring instrument or measuring system at a specified measured quantity value (JCGM 200:2012) Alternate Term: datum error Project: ISO IEC Guide 99
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datum measurement error measurement error of a measuring instrument or measuring system at a specified measured quantity value (JCGM 200:2012) Alternate Term: datum error Project: ISO IEC Guide 99
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daughter tube See aliquot container Project: AUTO12
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dead band maximum interval through which a value of a quantity being measured can be changed in both directions without producing a detectable change inthe corresponding indication (JCGM 200:2012) Project: ISO IEC Guide 99 NOTE: Dead band can depend on the rate of change (JCGM 200:2012).
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dead band maximum interval through which a value of aquantity being measured can be changed in both directions without producing a detectable change in the corresponding indication (JCGM 200:2012) NOTE 1: The dead band may depend on the rate of change; NOTE 2: The dead band is sometimes deliberately made large to prevent change in the response for small changes in the stimulus.
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dead space volume the volume of blood that would fill the length of a catheter lumen Project: H21 NOTE: This term is used in the collection of blood from indwelling vascular access devices.
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dead volume the retention volume of a container above which aspiration and dispense can be performed reliably Project: I/LA33
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dead-end corridor route that exceeds a specified length that does not lead to a fire exit NOTE: Lengths are determined by fire codes for a specific building type.
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deadleg a region or volume of stagnation in an apparatus or distribution system Alternate Term: dead volume Project: GP40
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deadspace ratio the ratio of physiologic deadspace (and instrument deadspace, if applicable) to tidal volume Alternate Term: pulmonary deadspace ratio, Vd/Vt Project: C12
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decadic absorbance the negative decadic logarithm of one minus the absorptance
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decapper part of an automation line at which the caps are taken off the specimen container
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decapping the removal of a closure from a specimen container Project: AUTO02
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decedent legal and general term meaning a person who has died Project: GP36
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decision analysis a derivative of operations research and game theory that involves identifying all available choices, and potential outcomes of each, in a series of decisions that have to be made about aspects of patient care—diagnostic procedures, therapeutic regimens, and prognostic expectations Project: GP45 NOTE 1: Epidemiologic data play a large part in determining the probabilities of outcomes following each choice that has to be made; NOTE 2: The range of choices can be plotted on a decision tree, and at each branch or decision node, the probabilities of each outcome that can be predicted are displayed; the decision tree thus portrays the choices available to those responsible for patient care and the probabilities of each outcome that will follow the choice of a particular action or strategy in patient care; NOTE 3: The relative worth of each outcome is preferably described as a utility or quality of life, eg, a probability of life expectancy or freedom from disability, often expressed as quality adjusted life years.
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decision level a test value or statistic that marks the upper (or lower) boundary between a negative (normal) or acceptable result and a positive (abnormal) or unacceptable result Alternate Term: decision point, cutoff level Project: GP10
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decision level a test value or statistic that marks the upper (or lower) boundary between diagnostic categories, ie, between negative (acceptable or unaffected) results and positive (unacceptable or affected) results Alternate Term: decision threshold; decision point; cutoff level Project: EP24
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decision matrix (prioritization matrix) evaluates and prioritizes a list of options Project: QMS14 NOTE 1: A list of weighted criteria is established, then each option is evaluated against those criteria; NOTE 2: A decision matrix is used when a list of options must be narrowed to one choice; when the decision must be made on the basis of several criteria; or after the list of options has been reduced to a manageable number by list reduction (adapted from ASQ).
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decision point (medical decision point) a concentration of the measurand that is used as a threshold for making a medical statement Project: EP09 NOTE: Often, decision points will refer to reference limits, but other concentrations, such as from medical guidelines, are also used.
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decision point See decision level Alternate Term: decision level; decision threshold; cutoff level Project: EP24
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decision point an amount of the measurand (eg, concentration, activity) that is used as a threshold for making a medical decision Alternate Term: medical decision point Project: EP07 NOTE: Often, decision points refer to reference limits, but other concentrations, such as from medical guidelines, are also used.
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decision threshold See decision level Alternate Term: decision level; decision point; cutoff level Project: EP24
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decontamination procedure that eliminates or reduces microbial or toxic agents to a safe level with respect to the transmission of infection or other adverse effects (ISO 15190) Alternate Term: infectious waste Project: ISO 15190, M29, QMS28, QMS04, QMS23 NOTE 1: Some disinfectants can be used for decontamination. These are intermediate or low-level disinfectants and in the United States, are regulated by the US Environmental Protection Agency for use on inanimate surfaces. They should not be used on medical devices that are used on patients; likewise, liquid chemical germicides formulated as sterilants or high-level disinfectants ordinarily are not used for purposes of decontamination because of the risk to personnel; NOTE 2: Sterilization and disinfection procedures are often used for decontamination of infectious waste; other procedures are available for chemical and radioactive material decontamination
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decontamination for infectious waste, a procedure that eliminates or reduces microbial contamination to a safe level with respect to the transmission of infection Project: GP05 NOTE: Sterilization and disinfection procedures are often used for decontamination of infectious waste; other procedures are available for chemical and radioactive material decontamination. See infectious waste.
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deconvolution a process of mathematically resolving something into its constituent components Project: C50 NOTE: It is applied to the separation of multiple charged spectra and/or chromatograms into their individual components.
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decreased susceptibility describes isolates with minimal inhibitory concentrations that are non–wild type but less than or equal to the susceptible clinical breakpoint Project: VET05, VET04
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dedicated circuit an independent electrical connection devoted to a specific piece of equipment Project: QMS04
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deep vein thrombosis an intravenous thrombus in a deep vein, usually in the proximal legs or pelvis, but may also occur in an upper extremity Alternate Term: deep venous thrombosis Project: H59
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deep venous thrombosis See deep vein thrombosis
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deep-seated lesion situated in the thoracic or abdominal organ/cavity Alternate Term: deep-seated mass Project: GP20 NOTE: It is usually not palpable and is visualized radiologically.
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deep-seated mass See deep-seated lesion Alternate Term: deep-seated lesion Project: GP20
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definitional uncertainty component of measurement uncertainty resulting from the finite amount of detail in the definition of a measurand (JCGM 200:2012) Project: ISO IEC Guide 99, C51 NOTE 1: Definitional uncertainty is the practical minimum measurement uncertainty achievable in any measurement of a given measurand (JCGM 200:2012); NOTE 2: Any change in the descriptive detail leads to another definitional uncertainty (JCGM 200:2012); NOTE 3: In the ISO/IEC Guide 98-3:2008, D.3.4, and in IEC 60359, the concept ‘definitional uncertainty’ is termed "intrinsic uncertainty" (JCGM 200:2012).
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definitive method analytical techniques that are designed to target specific drugs or drug metabolites Project: C63 NOTE 1: When adequately validated and controlled, these methods have the potential to be used to firmly identify a measurand of interest. The techniques considered capable of being used in this manner are two-dimensional and generally use chromatographic separation and mass spectrometric detection; NOTE 2: Definitive testing is not equivalent to confirmatory testing, which is a second analytically distinct method using a second unique aliquot to confirm a positive screening test; NOTE 3: A related term is targeted testing.
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definitive testing a procedure that is based on a different, more specific, physicochemical method than the original screening assay, and is used to confirm positive results; definitive tests can be qualitative or quantitative Alternate Term: confirmation analysis Project: C52 NOTE: A definitive test determines whether a specimen result is ultimately reported as positive or negative. Mass spectrometric techniques and other similar technologies are generally used for definitive testing.
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degradation the natural (hydrolysis), accidental (poor handling procedures), or induced (nuclease) destruction of a molecule into its component parts, especially as pertains to DNA and RNA integrity and stability Project: MM13
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deidentification the removal of names and other explicit identifiers from personal records Project: AUTO11 NOTE 1: Under the Health Insurance Portability and Accountability Act (HIPAA) Privacy Rule, data are deidentified if either: • An expert or statistician determines the risk that certain information could be used to identify an individual is “very small” and documents as well as justifies the determination, or • The data do not include any of the following 18 identifiers (of the individual, their relatives, household members, or employers) that could be used alone or in combination with other information to identify the subject: – Names – Geographic subdivisions smaller than a state (including zip code) – All elements of dates (except year) for dates that are directly related to an individual, including birth date, admission date, discharge date, death date, and all ages over 89 and all elements of dates (including year) indicative of such age, except that such ages and elements may be aggregated into a single category of age 90 or older – Telephone numbers – Fax numbers – E-mail addresses – Social Security numbers – Medical record numbers – Health plan beneficiary numbers – Account numbers – Certificate/license numbers – Vehicle identifiers, including license plates – Device identifiers and serial numbers (for patient care devices) – URLs – Internet protocol addresses – Biometric identifiers (eg, fingerprints, retina scan) – Full face photos and comparable images – Any unique identifying number, characteristic, or code NOTE 2: Even if the above identifiers are removed, the HIPAA Privacy Rule states that information is considered identifiable if the covered entity knows that the identity of the person may still be determined.
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deidentify use of a system that would create a new index that would relate to the patient Project: AUTO09 NOTE: This value would be sent in the data to the vendor. If information about a patient sample was required, the issuing institution would look up the information using this value. With this system, all the patient information would reside solely in the health care facility.
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deionization the removal of ions from a solution by ion exchange Project: ASTM08
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deionized water water resulting from the removal of ionized minerals and salts by ion exchange Project: QMS04
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deletion loss of one or more nucleotides from a nucleic acid sequence Project: MM18, MM22, MM24
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deletion the loss of DNA sequence from a chromosome Project: MM19 NOTE: The deleted DNA may be of any length from a single base to a large part of a chromosome.
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deletion the genetic process by which a segment of DNA is deleted or lost during replication Project: NBS09, NBS05 NOTE: The number of deleted nucleotides may vary from a single base pair to an entire gene or several neighboring genes.
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delimiter 1) a symbol used to separate items in a list; 2) in software data management, a bit, character, or set of characters used to denote the beginning or end of a group of related bits, characters, words, or statements. For example, the ampersand (&) in the character string "& APPLE &" (IEEE 610.5, 610.12) Project: AUTO01, AUTO02, AUTO03
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delimiter a character or sequence of characters marking the beginning or end of a unit of data, eg, a control character, blank space, comma, or other character or symbol that indicates the beginning or end of a character string, word, or data item Project: AUTO14
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delta change a change within a specified time frame between two consecutive examination results of the same measurand Project: GP47
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delta check a comparison of two consecutive results from a patient, based on specified criteria, as a quality improvement effort by the laboratory Project: EP33
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delta check alerts refer to situations in which differences between consecutive results exceed a specified delta check limit Project: EP33
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delta checks comparison of two consecutive results from a patient, based on specified criteria, as a laboratory quality improvement effort Project: AUTO15
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dematiaceous (phaeoid) having conidia, spores, or hyphae that are brown to black in color due to the presence of melanin Project: M54
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Deming regression a method to estimate slope and intercept parameters from a measurement procedure comparison experiment with allowance for both measurement procedures to have imprecision Project: EP09, EP14 NOTE: The measurement error for each measurement procedure is accounted for in the estimation procedure.
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demolition wrecking or removal of existing building components to allow new construction
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demonstration (study) a study performed by a laboratory to show that it is capable of using a test system to obtain expected performance Project: I/LA28 NOTE: Laboratories may conduct a demonstration study when they are considering the logistical decision about whether to purchase an immunohistochemistry assay or its components.
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demultiplexing the process of assigning next-generation sequencing reads to their samples of origin based on the sequence of their corresponding molecular bar codes Project: MM09
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denaturation the conversion of double-stranded DNA or RNA to a single-stranded state with minimal secondary structure Project: MM09, MM01 NOTE 1: Denaturation is performed by heating, increasing pH, or adding agents such as formamide or urea; NOTE 2: After they have been denatured, nucleic acid molecules are available for hybridization with a primer or probe.
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denaturation 1) loss of native structure or configuration of a macromolecule, usually with resulting loss of biological or immunological reactivity or solubility; 2) the conversion of double-stranded DNA or RNA to a single-stranded state with minimal secondary structure Project: MM10, MM12, MM24 NOTE: This is done by heating, increasing the pH, or adding agents such as formamide or urea; once denatured, nucleic acid molecules are available for hybridization with a primer or probe.
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denaturation (protein) disruption of the native structure of a protein molecule either with chemicals, such as acid, base, or detergents, or with heat Project: ILA29
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dendrogram a branching, tree-like diagram that illustrates the hierarchical relationships among sequences aligned by a multiple alignment tool Project: MM18 NOTE: A dendrogram is often called a “phylogenetic tree.”
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denial of service the prevention of authorized access to a system resource or the delaying of system operations and functions (RFC 2828) Project: AUTO09
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deoxypyridinoline pyridinium compound formed during collagen maturation by crosslinking lysine and hydroxylysin side chains from different collagen molecules Alternate Term: lysylpyridinoline Project: C48
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deoxyribonuclease any enzyme that catalyzes the hydrolytic cleavage of phosphodiester linkages in the DNA backbone Project: MM19 NOTE: A wide variety of deoxyribonucleases are known, which differ in their substrate specificities, chemical mechanisms, and biological functions.
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deoxyribonucleic acid (DNA) a type of nucleic acid; a polynucleotide having a specific sequence of deoxyribonucleotide units and serving as the carrier of genetic information Project: MM02, MM13 NOTE: DNA is a double-stranded molecule held together by weak hydrogen bonds between base pairs of nucleotides. The four nucleotides in DNA contain the bases adenine, guanine, cytosine, and thymine. Essentially, two forms of DNA can be distinguished: genomic DNA from the nucleus (nuclear DNA of the chromosomes) and mitochondrial DNA.
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deoxyribonucleic acid a type of nucleic acid; a polynucleotide having a specific sequence of deoxyribonucleotide units principally serves as the carrier of genetic information Alternate Term: DNA
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depletion analysis a procedure used to estimate the quantity of immunoglobulin E antibody in the calibration process of a prospective reference serum Project: I/LA20 NOTE: This technique has not been widely used for estimating the quantity of immunoglobulin G, immunoglobulin A, or immunoglobulin M antibody of defined antigen specificities in other prospective reference sera because the percentage of the total immunoglobulin of these isotypes that is specific antibody directed to a particular antigen is low generally in comparison to the percentage of immunoglobulin E that is specific for one allergen. This leads to inaccuracies that prevent the successful use of this method in calibrating reference sera. Using short ragweed as an illustrative allergen specificity, a potent immunoglobulin E antiragweed containing serum is first optimally preabsorbed with either ragweed-solid phase or a sham-solid phase. Three sera (unabsorbed, sham-absorbed, and ragweed-absorbed) are then analyzed in a total serum immunoglobulin E for their immunoglobulin E content. Difference in the total immunoglobulin E levels between the sham- and ragweed-absorbed serum represents the amount of specific immunoglobulin E that was depleted or removed from the serum by the solid-phase allergen. The sham-adsorbed immunoglobulin E antibody levels should be equivalent to unabsorbed serum levels. Elution of the ragweed-solid phase adsorbed immunoglobulin E antibody can be added to the procedure to validate the efficiency of the extraction procedure and provide an additional level of confidence in the specific antibody estimation.
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depletion analysis a procedure used to estimate the quantity of immunoglobulin E antibody in the calibration process of a prospective reference serum by removal of specific immunoglobulin E and detection of changes in total immunoglobulin E levels Project: I/LA34
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depth of coverage the number of unique reads of a given nucleotide in the reconstructed sequence Alternate Term: coverage Project: MM24
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depth of coverage in next-generation sequencing, the number of times a nucleotide or nucleic acid region is represented in sequence reads, with data aggregated to generate a consensus read or sequence Project: MM09 NOTE: Depth of coverage is often expressed as a mean number across the full sequence of a sample or for a target region.
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derivative the instantaneous rate of change of a function, defined as the limit of the rate of change over a time interval Δt when Δt tends to zero. For example, the derivative G' (t) = limΔt→0 ΔG÷Δt represents the instantaneous rate of change of glucose fluctuation at time t
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derivative tube See aliquot container Project: AUTO12
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derivatization selective chemical alteration of analyte functional groups Project: NBS04 NOTE 1: Derivatization is usually performed to improve sensitivity, selectivity, or retention characteristics; NOTE 2: In the case of newborn screening, the carboxylic acid functional groups are most often converted to butyl esters.
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derived quantity quantity, in a system of quantities, defined in terms of the base quantities of that system (JCGM 200:2012) Project: ISO IEC Guide 99 EXAMPLE 1: In a system of quantities having the basequantities length and mass, mass density is a derivedquantity defined as the quotient of mass and volume(length to the third power) (JCGM 200:2012); EXAMPLE 2: In a system having base quantities length, mass, and time, velocity is a derived quantity defined as length divided by time.
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derived unit measurement unit for a derived quantity (JCGM 200:2008) Project: ISO IEC Guide 99 EXAMPLES: The metre per second, symbol m/s, and the centimetre per second, symbol cm/s, are derived units of speed in the SI. The kilometre per hour, symbol km/h, is a measurement unit of speed outside the SI but accepted for use with the SI. The knot, equal to one nautical mile per hour, is a measurement unit of speedoutside the SI (JCGM 200:2012).
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derived unit (of measurement) unit of measurement of a derived quantity in a given system of quantities (VIM93-1.14)
NOTE: Some derived units have special names and symbols; for example, inthe SI: | Quantity | SI derived unit | | Name | Symbol | | force energy pressure | newton joule pascal | N J Pa |
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dermatophyte a fungus that obtains nutrients from keratin and infects skin, hair, and nails; consists of species within the genera Microsporum, Trichophyton, and Epidermophyton Project: M54
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descriptive safety the requirements and procedures for installation, use, and monitoring of medical devices to ensure their continued safety (ISO Guide 63-2.3) Project: ISO Guide 63-2.3
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design a part of the Feasibility and Design Phase in the Establishment Stage of the Test Life Phase Model. Design considerations should include whether a new test method could have performance characteristics that meet needs in a way that is lacking from an existing test method, and/or whether it would meet a f need that is not currently met (or better meet the need in terms of speed, cost, sensitivity, specificity, etc.) Project: EP19 NOTE 1: The intended use is agreed on during the design portion of the Feasibility and Design Phase; NOTE 2: Relevant system specifications should be established during the Feasibility and Design Phase. During the Development Phase, the test method is iteratively optimized to meet these specifications.
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design controls the interrelated set of practices and procedures that are incorporated into the design and development process, ie, a system of checks and balances Project: I/LA28 NOTE: Design controls make systematic assessment of the design an integral part of development. As a result, deficiencies in design input requirements and discrepancies between the proposed designs and requirements are made evident and corrected earlier in the development process. Design controls increase the likelihood that the design transferred to production will translate into a device that is appropriate for its intended use.
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design development third design phase of a construction project, in which the plans generated in the previous phase (schematic design) are drawn in greater detail, more engineering information is incorporated, and the elevations are generated
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design input requirements the physical and performance requirements of a product that are used as a basis for product design Project: EP25
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designated comparison method a fully specified method(s), which, in the absence of an NRSCL-credentialed reference method, serves as the common basis for the comparison of “field” reference materials and methods, and for the development of principal assigned values or principal assigned characteristics for an analyte or process Project: NRSCL13, C44
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desk audit review of documents, usually performed at a desk using the audited organization’s documentation Project: QMS15 NOTE: Method to review documents to prepare for an audit.
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detectability the ability to discover or determine the existence, presence, or fact of a hazard Project: EP23
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detectability the ability of an analytical method to detect small quantities of the component (IFCC-1978-QC Terminology)
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detection capability umbrella term for a set of performance attributes that can be used to characterize measurement accuracy in the low-end region of the measuring interval. These performance attributes are limit of blank, limit of detection, and limit of quantitation Project: EP19
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detection capability an umbrella term for a set of performance attributes that may be used to characterize measurement accuracy in the low-end region of the measuring interval Project: EP35, H62 NOTE 1: The term “sensitivity” and its variants “analytical sensitivity” and “functional sensitivity” are not used in CLSI EP35 or the main text of CLSI H62 because of the existence of several conflicting common uses of these terms across multiple technical disciplines. “Limit of detection” is the preferred term for the detection capability attribute previously associated with analytical sensitivity because of its more precise definition and common use. Similarly, “limit of quantitation” is the preferred term for the detection capability attribute previously associated with functional sensitivity (ie, denoting quantitative detection of a measurand in a sample with known measurement accuracy); NOTE 2: Signaling presence of a measurand in a sample; NOTE 3: See sensitivity, analytical.
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detection limit measured quantity value, obtained by a given measurement procedure, for which the probability of falsely claiming the absence of a component in a material is β, given a probability α of falsely claiming its presence (JCGM 200:2012) Alternate Term: limit of detection; lower limit of detection Project: NBS07, NBS04, C52, NBS09, MM17, EP39 NOTE 1: The International Union of Pure and Applied Chemistry recommends default values for α and β equal to 0.05 (JCGM 200:2012); NOTE 2: The abbreviation LOD is sometimes used (JCGM 200:2012); NOTE 3: The term “sensitivity” is discouraged for ‘detection limit’ (JCGM 200:2012); NOTE 4: Also called “limit of detection” and “minimum detectable concentration” (or dose or value); sometimes used to indicate “analytical sensitivity”; NOTE 5: In quantitative and qualitative molecular measurement procedures, the lowest concentration of analyte that can be consistently detected (typically, in ≥ 95% of samples tested under routine medical laboratory conditions).
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detection limit the lowest concentration of analyte that can be reported to be present at a specified level of confidence, often taken to be the analyte concentration that reports a signal three standard deviations above the background Project: MM12
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detection limit the smallest quantity of an analyte that can be reproducibly and statistically distinguished from the background (including variation in background), or a zero calibrator in a given assay system Alternate Term: limit of detection Project: I/LA34 NOTE 1: It is usually defined at the 95% confidence interval and has also been called the lower detection limit or positive threshold of the assay; this term is not synonymous with analytical sensitivity; NOTE 2: Assuming an adequate number of samples and that their distributions are similar, an equivalent distribution between the 0 calibrator and low positives, the 95% confidence interval means 1.645 standard deviations between the mean levels produced by the 0 calibrator and the low positives. The positive cutoff level should, therefore, be greater than 1.645 standard deviations from the mean of the 0 calibrator. See CLSI document EP17.
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detection mechanism means or methods by which a failure can be discovered by an operator under normal system operation or can be discovered by the maintenance crew by some diagnostic action (MIL-STD-1629A. Procedures for Performing a Failure Mode, Effects and Criticality Analysis. 24 November 1980.)
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detection rate proportion of affected individuals with positive test results Project: I/LA25
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detector device or substance that indicates the presence of a phenomenon, body, or substance when a threshold value of an associated quantity is exceeded (JCGM 200:2008) Project: ISO IEC Guide 99 EXAMPLES: Halogen leak detector, litmus paper (JCGM 200:2012); NOTE 1: In some fields, the term "detector" is used for the concept of sensor (JCGM 200:2012); NOTE 2: In chemistry, the term "indicator" is frequently used for this concept (JCGM 200:2012).
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detector device or substance that indicates the presence of a phenomenon without necessarily providing a value of an associated quantity (VIM93-4.15); EXAMPLES: a) halogen leak detector; b) litmus paper Project: VIM93 NOTE 1: An indication may be produced only when the value of the quantity reaches a threshold, sometimes called the "detection limit" of the detector; NOTE 2: In some fields, the term "detector" is used for the concept of "sensor."
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determinant archaic, a gene
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determinant an algebraic expression of the sum of products of elements, each with an appropriate algebraic sign, usually written in a square array and used in the solution of systems of linear equations
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determinant a determining agent or factor Project: NRSCL8
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determinant See and use epitope or antigenic determinant Alternate Term: Epitope, antigenic determinant
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developer the term “developer” is used in CLSI EP45 to include notonly commercial manufacturers of test methods but also laboratories thatdevelop their own (eg, based on published literature) or modifyregulatory-cleared and -approved commercial test methods forimplementation in their own facility Project: EP19, EP45 NOTE: Also known as a laboratory-developed test.
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development phase in the Establishment Stage of the Test Life Phase Model. During development, a test method is transitioned from initial conception through lockdown using systematic, iterative improvements in hardware, software, reagents, and other system design elements, to optimize performance to meet specifications Project: EP19
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deviation value minus its reference value
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device an instrument (measuring system) that gives analytical answers as a result of electrical or mechanical measurements on an element, compound, solution, etc. Project: AUTO01, EP10, AUTO02, AUTO03, POCT07, POCT04 NOTE 1: The measurement is often made before and after a chemical or physical reaction; the resultant measurement can be applied to give a final analytical result; NOTE 2: Device is a term that represents a range of diagnostic instruments deployed in point-of-care testing. Devices may include but are not limited to small portable or semiportable systems, benchtop analyzers, handheld devices, and single-use test kits having built-in readers as part of the consumable; 1) any device or combination of devices used for the diagnosis or treatment of injury, or temporary or permanent physical disability, which does not achieve its effect by chemical means, although it may be used in combination with a substance that does (ISO Guide 63-2.9); 2) any medical device which is a reagent, reagent product, calibrator, control material, kit, instrument, apparatus, equipment or system, whether used alone or in combination, intended by the manufacturer to be used in vitro for the examination of specimens, including blood and tissue donations, derived from the human body, solely or principally for the purpose of providing information concerning congenital abnormality, or to determine the safety and compatibility with potential recipients, or to monitor therapeutic measures; 3) in Automation, a unit to prepare specimens for analysis, or to handle specimens after they have been analyzed by another instrument, eg, automated centrifuges, automated aliquoters, automated storage, and retrieval; NOTE 3: In point-of-care testing, the term represents a range of diagnostic systems that may include, but are not limited to, small portable or semiportable systems, benchtop analyzers, handheld devices, cassettes, and single-use test kits having built-in readers as part of the consumable.
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device and access point interface specifies the interface between a device and an access point or concentrator Project: POCT01
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device and access point interface specifies the interface or communication connection between a device and an access point Alternate Term: DAP Project: POCT02
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device communication controller specifies the interface (principally output) of a point-of-care device or its docking station to an access point Project: POCT01 NOTE: This is an IEEE definition, equivalent to “point-of-care device interface.”
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device end user end user in the health care delivery organization familiar with the medical device and its operation Project: AUTO11
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device messaging layer the device messaging layer describes a complete messaging protocol (message types and message flow) to exchange results and quality information (quality assurance and quality control) between a device and an observation reviewer Project: POCT01 NOTE: This protocol may sit on top of any robust, reliable transport, such as the one described by the POCT01 device and access point specification.
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Dextramer (or the equivalent) See MHC Dextramer® (or the equivalent) Project: I/LA26
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diagnostic accuracy the ability of a diagnostic test to method discriminate between diseased and nondiseased subjects or between two or more clinical states Alternate Term: clinical accuracy Project: EP24, POCT13, EP19 EXAMPLE: discrimination between rheumatoid arthritis and systemic lupus erythematosus.
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diagnostic accuracy the extent of agreement between the information from the test under evaluation and the diagnostic accuracy criteria Project: M55 NOTE 1: Diagnostic accuracy can be expressed in different ways, including sensitivity-specificity pairs, likelihood ratio pairs, and the area under a receiver operating characteristic curve; NOTE 2: Diagnostic accuracy must be interpreted in context with the condition of interest and the combination of specific criteria and methods used; NOTE 3: Diagnostic accuracy is not the same as accuracy, which is the closeness of a single result of a measurement and a true value.
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diagnostic accuracy the ability of a test system to obtain the correct result, including both sensitivity and specificity Project: MM03, MM22
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diagnostic accuracy criteria the best currently available criteria for establishing the presence or absence of the condition, event, or characteristic of interest using a single method or combination of methods including laboratory tests, imaging tests, pathology, and clinical information including follow-up NOTE 1: The diagnostic accuracy criteria will evolve with the advancement of analytical systems, and may in a given situation be different from diagnostic accuracy criteria so determined by a regulatory or metrology agency; NOTE 2: Diagnostic accuracy criteria do not consider the outcome of the candidate test (new test under evaluation). Diagnostic accuracy criteria can be an algorithm specifying the choice and ordering of a combination of methods and how the different results are combined to make a final positive/negative classification.
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diagnostic sensitivity the proportion of subjects with a well-defined clinical disorder (or condition of interest) whose test values are positive or exceed a defined decision limit (ie, a positive result and identification of the patients who have a disease) Project: MM10, MM12, C50, MM17, EP18, I/LA28, MM19, MM14, H60, MM03, MM23 NOTE 1: The clinical disorder must be defined by criteria independent of the test under consideration; NOTE 2: The term “clinical sensitivity” (United States) is equivalent to “diagnostic sensitivity” (Europe); NOTE 3: It is the fraction of clinically true-positive classifications divided by the sum of clinically true-positive and clinically false-negative classifications; NOTE 4: The probability (P) that the test is positive (T+), given that the subject being tested is disease/state positive (D+), ie, P (T+|D+); or, the ability of a test under study to give a positive result for subjects having the disease/state in question; NOTE 5: For the purposes of C50, a more practical definition relates to the signal-to-noise ratio; NOTE 6: The term sensitivity is often used as a synonym for the lowest concentration of an analyte that can be distinguished from background; NOTE 7: The clinical disorder should be defined by criteria independent of the test under consideration; NOTE 8: In Europe, the term “clinical” applies mostly to clinical studies of drugs, under much more stringent conditions.
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diagnostic sensitivity the proportion of patients with a well-defined clinical disorder whose test values are positive or exceed a defined decision limit, ie, a positive result and identification of the patients who have a disease (disorder, or condition) Project: I/LA23 NOTE 1: The clinical disorder (eg, hypoglycemia or hyperglycemia) must be defined by criteria independent of the test under consideration; NOTE 2: The European term “diagnostic sensitivity” is equivalent to the US term “clinical sensitivity”; NOTE 3: It is the fraction of clinically true positives divided by the sum of clinically true-positive plus clinically false-negative classifications; NOTE 4: In Europe, the term “clinical” applies mostly to clinical studies of drugs, under much more stringent conditions; NOTE 5: For purposes of continuous glucose monitoring, diagnostic sensitivity refers to effectiveness of detection of hypoglycemia or hyperglycemia. Sensitivity = true positives/(true positives + false negatives).
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diagnostic sensitivity the probability (P) that the test is positive (T+), given that the subject being tested is disease positive (D+), ie, P(T+|D+); or, the ability of a test under study to give a positive result for subjects having the disease in question Project: M55
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diagnostic sensitivity the ability of a measurement procedure to give a positive result for subjects who have the disease or condition for which they are being measured Project: EP33, I/LA20 NOTE: In the context of EP33, diagnostic sensitivity refers to the ability of a particular delta check rule to detect patient samples that have identification or integrity issues, or to detect clinically important changes in patient conditions.
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diagnostic sensitivity 1) as used in CLSI document I/LA02, the ability of a test to correctly identify samples in which antinuclear antibodies are present; 2) as used in CLSI document I/LA34, the ability of a test to correctly identify samples in which allergen-specific immunoglobulin E antibody is present; it correlates the presence of allergen-specific immunoglobulin E antibody in the serum of patients who are defined by clinical criteria and/or designated reference laboratory tests as truly allergic Project: I/LA02, I/LA34 NOTE 1: Sensitivity for antinuclear antibodies is ideally determined by testing a panel of serum samples previously determined to be positive for antinuclear antibodies by an accepted reference method or consensus evaluation. This serum panel should reflect samples from a variety of disease states in which antinuclear antibodies are found; NOTE 2: Sensitivity for immunoglobulin E antibody is ideally determined by testing a panel of serum samples from subjects with a positive history of allergic disease and evidence of immunoglobulin E antibody positivity by an alternative accepted method such as skin testing, provocation testing, and/or an accepted reference serology method (provided its sensitivity and specificity are known). The serum panel should reflect patients from a variety of allergic disease states relevant to that allergen specificity as well as healthy nonatopic controls.
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diagnostic sensitivity the ability of a measurement procedure under study to give a positive result for subjects having the disease/target condition in question Project: EP19 NOTE: Formerly, the term “clinical sensitivity” was used in CLSI documents.
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diagnostic sensitivity as used in I/LA34, the ability of a test to correctly identify samples in which allergen-specific immunoglobulin E antibody is present; it correlates the presence of allergen-specific immunoglobulin E antibody in the serum of patients who are defined by clinical criteria and/or designated reference laboratory tests as truly allergic Alternate Term: clinical sensitivity Project: I/LA34 NOTE: Sensitivity for immunoglobulin E antibody is ideally determined by testing a panel of serum samples from subjects with a positive history of allergic disease and evidence of immunoglobulin E antibody positivity by an alternative accepted method such as skin testing, provocation testing, and/or an accepted reference serology method (provided its sensitivity and specificity are known). The serum panel should reflect patients from a variety of allergic disease states relevant to that allergen specificity as well as healthy nonatopic controls.
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diagnostic sensitivity the proportion of patients with a well-defined clinical disorder whose test values are positive or, as in the case with the lamellar body count, below a defined decision limit (ie, a positive result and identification of the patients who have a disease) Project: C58 NOTE 1: The clinical disorder must be defined by criteria independent of the test under consideration; NOTE 2: The term “diagnostic sensitivity” (Europe) is equivalent to “clinical sensitivity” (United States).
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diagnostic specificity the ability of a measurement procedure to give a negative result for subjects who do not have the disease or condition for which they are being measured Project: EP33 NOTE: In the context of EP33, diagnostic specificity refers to the ability of a delta check rule to correctly exclude patient samples that do not have identification or integrity issues, and correctly exclude samples from patients who do not have clinically important changes in their conditions.
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diagnostic specificity the proportion of subjects who do not have a specified clinical disorder (or condition of interest) whose test results are negative or within the defined decision limit Project: I/LA21, I/LA23, MM10, MM03, MM12, C50, MM17, I/LA28, MM19, H60, MM23 NOTE 1: It is the fraction of clinically true-negative classifications divided by the sum of clinically true-negative plus clinically false-positive classifications; NOTE 2: This term is equivalent to the US term “clinical specificity”; NOTE 3: In laboratory testing, the ability of a test to give a negative result for patients who do not have the disease or condition for which they are being tested. It is measured as the ratio of negative tests to the total number of tests in those who do not have the disease or condition and expressed as a percentage; NOTE 4: In Europe, the term “clinical” applies mostly to clinical studies of drugs, under much more stringent conditions; NOTE 5: Diagnostic sensitivity pertains to test results rather than analytical measurements; NOTE 6: For purposes of continuous glucose monitoring, diagnostic specificity refers to effectiveness of detection of the absence of hypoglycemia or hyperglycemia. Specificity = true negatives/(true negatives + false positives); NOTE 7: The probability (P) that the test is negative (T−), given that the subject being tested is disease free (D−), ie, P(T− | D−); or, the ability of a test under study to give a negative result for subjects not having the disease in question; NOTE 8: The term “clinical specificity” (United States) is equivalent to “diagnostic specificity” (Europe).
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diagnostic specificity the ability of a test to give a negative result for patients who do not have the disease or condition for which they are being tested Project: M55 NOTE: It is measured as the ratio of negative tests to the total number of tests in those that do not have the disease or condition and is expressed as a percentage.
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diagnostic specificity as used in CLSI document I/LA02, the ability of a test to correctly identify samples in which antinuclear antibodies are absent Project: I/LA02 NOTE: Specificity for antinuclear antibodies is ideally determined by testing a panel of serum samples previously determined to be negative to antinuclear antibodies by an accepted reference method or consensus evaluation. This serum panel should reflect samples from a variety of disease states as well as normal samples.
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diagnostic specificity the ability of a measurement procedure under study to give a negative result for subjects not having the disease/target condition in question Project: EP19, I/LA20 NOTE: Formerly, the term “clinical specificity” was used in CLSI documents.
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diagnostic specificity as used in I/LA34, the ability of a test to correctly identify samples in which allergen-specific immunoglobulin E antibody is absent; it correlates the absence of allergen-specific immunoglobulin E antibody in the serum of patients who are defined by clinical criteria and/or designated reference laboratory tests as truly not allergic Alternate Term: clinical specificity Project: I/LA34 NOTE: Specificity for immunoglobulin E antibody is ideally determined by testing a panel of serum samples from subjects with a negative history of allergic disease and evidence of the absence of immunoglobulin E antibody positivity by an alternative accepted method such as skin testing, provocation testing, and/or an accepted reference serology method (provided its sensitivity and specificity are known). The serum panel should reflect patients from a variety of allergic disease states relevant to that allergen specificity as positive controls as well as healthy nonatopic negative controls.
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diagnostic specimen excreta, secreta, blood, and its components, tissue, tissue fluids, etc., that may contain an etiologic agent and is used for diagnosis Project: GP05
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diagnostic specimen any human or animal material, including but not limited to excreta, blood and its components, and tissue and tissue fluids collected for the purposes of diagnosis but excluding live infected animals Project: PRE04
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diagnostic specimen See patient specimen Alternate Term: patient specimen; clinical specimen Project: M29
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diagnostic test a measurement or examination of a diagnostic specimen for the purpose of diagnosis, prevention, or treatment of any disease or the assessment of health or impairment of health of an individual patient Project: ISO TR 15196, MM10, MM12, MM01, I/LA28, MM22, MM24 NOTE 1: Laboratory tests are often called in vitro diagnostic tests; NOTE 2: Diagnostic tests are generally performed to evaluate the genetic status of 1) symptomatic individuals, 2) those who are at increased risk for a particular disorder due to a positive family history, or 3) to confirm the findings of a prior screening test.
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diagnostic test a measurement or examination used to classify subjects into a particular class or clinical state Project: EP24 NOTE: Laboratory tests are often called “in vitro diagnostic” tests.
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diagnostic testing an additional test with very high specificity that may be performed, usually following another diagnostic test of lower specificity, in order to confirm or not confirm the original result Alternate Term: confirmatory testing; supplemental testing Project: MM10 NOTE 1: The first line of diagnostic tests or “screening tests” are generally optimized for sensitivity and high throughput but may lack somewhat in specificity (ie, they are prone to returning false-positive results); NOTE 2: Supplemental tests may be more labor-intensive and thus less suited for screening activity but should either have higher specificity or be based on detection of a different marker, such that the two tests in tandem will return very high sensitivity and specificity.
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diagnostic testing 1) testing generally performed to evaluate the genetic status of individuals at increased risk for a particular disorder due to a positive family history or symptoms; 2) a test that confirms the presence or absence of a substance by another methodology or procedure that is either more sensitive, more specific, or both; 3) a clinical condition as a follow up to testing previously performed that indicated the patient being at higher risk for having a clinical condition Alternate Term: confirmatory testing Project: MM12
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dial fixed or moving part of a displaying device that carries the scale or scales Project: VIM93 NOTE: In some displaying devices, the dial takes the form of drums or discs bearing numbers and moving relative to a fixed index or window. (VIM93)
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dichotomous acute angle branching into two equal branches Project: M54
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dideoxynucleotides nucleotides lacking a 3'-hydroxyl (-OH) group on their deoxyribose sugar Alternate Term: ddNTPs Project: MM18
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dielectric constant the measure of a sample’s ability to obstruct the microwave energy as it passes through the medium; the loss (dielectric) factor measures the sample’s ability to dissipate that energy Project: GP28 NOTE: The term “loss” is used to indicate the amount of input microwave energy that is lost to the sample by being dissipated as heat in the sample.
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diethylstilbestrol synthetic, nonsteroidal estrogens administered during the last century to gravid women at risk for early pregnancy loss Project: GP15 NOTE: There is evidence that administration may have caused adenosis (non-neoplastic) and clear cell adenocarcinoma (neoplastic) in the female genital (cervix and vagina) tract of some of the daughters who were exposed in utero.
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difference plot a plot of the difference between a measured value and a reference concentration plotted on the y-axis vs the reference concentration on the x-axis Project: EP10, EP09 NOTE 1: Often, a dashed line is drawn at zero difference; NOTE 2: The reference concentration is often expressed as the average of the results of the measurements; NOTE 3: The difference may be expressed relative to the reference concentration; NOTE 4: For presentation of data for validation purposes, the reference concentration should be comparative measurement procedure values.
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different in bacterial strain typing, the results for two isolates are described as “different” based on predefined criteria; this characterization implies that the isolates are not derived from a common (recent) ancestor Project: MM11, MM24 NOTE 1: The process for establishing such criteria is discussed in Section 9 of CLSI document MM11; NOTE 2: See also indistinguishable.
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differentiation assay an assay that distinguishes between HIV-1 and HIV-2 antibodies Project: M53
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difficult sample a specimen or sample that is inherently unstable, of limited quantity, heterogenous, or possessing other characteristics that make it unsuitable for storage and testing over time Project: EP25
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diffuse reflection the reflection of light from a surface such that an incident ray is reflected at many angles, rather than at just one angle Project: AUTO14 NOTE 1: Light is reflected from an object in two different ways: specular (mirror-like) and diffuse; NOTE 2: The proportions between the two types are dependent on the surface properties of the object being illuminated. A matte white surface produces a reflection that is almost exclusively diffuse, resulting in very limited specular reflection. Inversely, an optical-grade mirror produces a reflection that is almost exclusively specular, resulting in very limited diffuse reflection. For practical purposes, diffuse reflection’s light distribution can be considered to be omnidirectional; NOTE 3: On typical label-stock, diffuse reflection will be present and is used for reading bar code symbols
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DiGeorge syndrome a clinical diagnosis referring primarily to a syndrome with a conotruncal heart defect, hypoparathyroidism, and aplasia or hypoplasia of the thymus gland. Variable additional findings have been noted (see 22q11.2 deletion syndrome) Project: NBS06 NOTE 1: Not all patients with a clinical diagnosis of DiGeorge syndrome will have a deletion of 22q11.2; NOTE 2: Patients with DiGeorge syndrome may be described as having complete or partial DiGeorge syndrome based on the severity of the thymic defect. “Partial” DiGeorge syndrome comprises 99% of patients who have a normal or hypoplastic thymus. Approximately 1% of patients have “complete” DiGeorge syndrome; absence of development of the thymus and an absence of T-cells in the peripheral blood resulting in a profound impairment of cellular immunity, similar to severe combined immunodeficiency. Newborns with complete DiGeorge syndrome will likely be identified by the T-cell receptor excision circle assays used for severe combined immunodeficiency newborn screening. They will require immune reconstitution (eg, thymic transplantation); NOTE 3: Newborn screening programs have observed infants with partial DiGeorge syndrome with low T-cell receptor excision circle levels at birth which increase over time, eventually reaching the normal range.
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digestion chemical or enzymatic process used to cleave proteins into smaller fragments, typically peptides Project: C64
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digital measuring instrument digital indicating instrument measuring instrument that provides a digitized output or display NOTE: This term relates to the form of presentation of the output or display, not to the principle of operation of the instrument.
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digital signal processors (DSP) electronic components of instruments that change or analyze in real time information that was digitized from analog signals Project: I/LA24
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digital signature a value computed with a cryptographic algorithm and appended to a data object in such a way that any recipient of the data can use the signature to verify the data’s origin and integrity (RFC 2828) Project: AUTO09
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Digital Signature Algorithm an asymmetric cryptographic algorithm that produces a digital signature in the form of a pair of large numbers. The signature is computed using rules and parameters such that the identity of the signer and the integrity of the signed data can be verified (See Digital Signature Standard) (RFC 2828) Project: AUTO09
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Digital Signature Standard the US government standard that specifies the Digital Signature Algorithm, which involves asymmetric cryptography (RFC 2828) Project: AUTO09
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diluent the material used to make a concentrated material weaker Project: NRSCL08, H51 NOTE 1: The diluent is usually a liquid or a gas; NOTE 2: A liquid diluent may also be used to reconstitute a dried material to its original concentration.
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dilution the process of adding a material, usually a liquid or gas, to another material or substance for purposes of decreasing the concentration or activity of the former Project: H48
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dimension of a quantity expression that represents a quantity of a system of quantities as the product of powers of factors that represent the base quantities of the system (VIM93);EXAMPLES:a) in a system having base quantities length, mass and time, whose dimensions are denoted by L, M and T respectively, LMT-2 is the dimension of force;b) in the same system of quantities, ML-3 is the dimension of mass concentration as well as of mass density NOTE 1: The factors that represent the base quantities are called "dimensions" of these base quantities; NOTE 2: For details of the relevant algebra, see ISO 31-0.
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diode a device that conducts electric current run in one direction only Project: GP28
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dipolar molecules molecules that are configured such that electrons favor one region of the molecule, resulting in an uneven spatial distribution of electrons and charge so that one side is slightly negatively charged relative to the somewhat more positively charged other side Project: GP28
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dipole rotation the net alignment, due to the electric field, of molecules in the sample that have permanent or induced dipole moments Project: GP28
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direct analysis measurement made directly on an undiluted specimen, eg, whole blood, plasma, or sweat Project: C29
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direct antiglobulin test a test in which antihuman globulin is used to determine whether red blood cells have been coated in vivo with immunoglobulin G, complement, or both Project: I/LA33
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direct Coomb’s test See direct antiglobulin technique
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direct cost a cost that is identifiable directly with a particular activity, service, or product of the program experiencing the costs Project: GP45
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direct cost an expense that can be traced directly to (or identified with) a specific cost center or cost object such as a department, process, or product and that is usually under the control and responsibility of the department manager Project: QMS20 NOTE: Direct costs include costs such as labor, reagents, or supplies that vary with the rate of output but are uniform for each unit of production.
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direct FTH measurement procedures measurement procedures in which hormone is isolated from the protein-bound moiety prior to direct measurement of the amount sequestered (eg, by immunoassay) Project: C45
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direct INR determination international normalized ratio determination from a prothrombin time/international normalized ratio calibration line determined using certified plasmas without employing an international sensitivity index and mean normal prothrombin time Project: H54, H47
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direct lighting light that is directed downward toward the work surface Project: QMS04
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direct method measurement method in which the value of a measurand is measured directly, in the specimen, without diluting the specimen with reagents and without the need for supplementary calculations based on a functional relationship between the measurand and other quantities actually measured Project: EP34
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direct methods experimental verification methods that rely on sample data collected for the purpose of verification
Project: EP45
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direct oral anticoagulant group of oral agents composed of direct thrombin inhibitors and direct factor Xa inhibitors Project: POCT14
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direct oral anticoagulant orally administered therapeutic agent that targets a specific factor (eg, factor Xa or factor IIa) to inhibit coagulation Project: H21
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direct reading photometer a photometer with a measurement scale that has been calibrated directly in units of the analyte measured NOTE 1: If the analyte is hemoglobin, then the device might be termed a hemoglobinometer; NOTE 2: This should be contrasted with the special case spectrophotometer, which has the additional characteristic of being able to control the frequency and/or wavelength of the source light.
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direct reading photometer a photometer whose measurement scale has been calibrated directly in units of hemoglobin concentration Project: H15 NOTE 1: These units may be grams per liter (g/L), or millimoles per liter (mmol/L); NOTE 2: An alternative term sometimes used is “hemoglobinometer.”
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direct smear (stool) approximately 2-mg suspension of feces in water or saline for the purpose of examination for parasites; primary aim is to see motility Project: M28
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direct susceptibility test a procedure based on inoculation of drug-containing media directly with a processed (concentrated after digestion and decontamination) specimen that is smear-positive for acid-fast bacilli to determine the proportion or percentage of resistant Mycobacterium tuberculosis complex in the patient’s bacterial population Project: M24
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direct thrombin inhibitor a class of drugs (either oral or intravenous) that directly inhibit the enzyme thrombin (without the need for a cofactor) Project: H47
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direct track sampling the process in which aspiration of a sample occurs directly from the specimen container while it is on the transportation system, whereby the instrument probe extends to reach the specimen container on the transportation system Project: AUTO07, AUTO02 NOTE: The integrity of this process requires reliable agreement between the transportation system and the instrument and specimen processing and handling devices regarding point of reference to guide movement of the probe to the specimen.
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directional airflow air supply and exhaust system that is laid out to guide the movement of air in a specific direction Project: QMS04
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directions for use See instructions for use
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directions of the specimen the orthogonal axes Alternate Term: directions of the sample; transportation system; instrument or specimen processing and handling device interfaces Project: AUTO02
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director the person designated as having primary responsibility for the point-of-care blood glucose testing service Project: POCT12, POCT, POCT17
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disaggregation the process by which platelet aggregates become separated into single platelets, resulting in a reversible change in transmittance or impedance Project: H58
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disaster state of a community threat to life and property of unusual magnitude that exhausts or threatens to overwhelm local resources Project: GP36 NOTE 1: In GP36, it is assumed that the disaster is of great magnitude, likely to be associated with a large number of injured, contaminated, or dead; NOTE 2: It is synonymous with “incident” or “event.”
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disaster a serious disruption of the functioning of a community or a society involving widespread human, material, economic, or environmental losses and impacts, which exceeds the ability of the affected community or society to cope using its own resources Project: POCT16
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disaster mortuary operations team (DMORT) a multidisciplinary forensic team which, with necessary support equipment, can be deployed to assist in the investigation of a mass fatalities incident NOTE 1: DMORT operates under the auspices of NDMS and can be activated under several legal authorities; NOTE 2: DMORT is accessed by the local medical examiner/coroner through a request to their EMA.
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discrepant result result that is inconsistent to a medically significant degree with another result obtained from the same sample, with a result from another measurement procedure, or with a well-substantiated medical diagnosis Alternate Term: anomalous result; spurious result Project: EP07, C56 NOTE: In C56, the “discrepant result//spurious result” would be a result inconsistent with another result obtained from the same sample in the absence of any clinically significant bias due to hemolysis, icterus, or lipemia/turbidity interference.
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discrimination (threshold) largest change in a stimulus that produces no detectable change in the response of a measuring instrument, the change in the stimulus taking place slowly and monotonically (VIM93) NOTE: The discrimination threshold may depend on, for example, noise (internal or external) or friction. It may also depend on the value of the stimulus.
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discrimination assay a serological assay that distinguishes among HIV antigens or HIV-1 and HIV-2 antibodies or a molecular assay that distinguishes between HIV-1 and HIV-2 RNA Project: M53
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discrimination threshold largest change in a value of a quantity being measured that causes no detectable change in the corresponding indication (JCGM 200:2008) Project: ISO IEC Guide 99 NOTE: Discrimination threshold may depend on, eg, noise (internal or external) or friction. It can also depend on the value of the quantity being measured and how the change is applied (JCGM 200:2012).
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discriminatory power in bacterial strain typing, the probability that two random, epidemiologically unrelated isolates will be distinguished by the typing method (ie, identified as different strain types) Project: MM11, MM24 NOTE: Ideally, each unrelated isolate is detected as unique, but, in practice, some are indistinguishable.
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disinfectant a substance used to reduce the concentration of bacteria, fungi, or viruses on a surface Project: M47
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disinfectant agent capable of disinfecting inanimate surfaces (eg, work surfaces or medical devices) (modified from ISO 15190) Project: M29, POCT13, POCT16 NOTE 1: Most disinfectants are not effective sterilizers; NOTE 2: See disinfection.
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disinfectant agent capable of causing disinfection (ISO 15190) Project: ISO 15190
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disinfection process to reduce the number of microorganisms, but not usually of bacterial spores, without necessarily killing or removing all organisms (ISO 15190) Project: ISO 15190, QMS28, QMS23, POCT16 NOTE: Chemical germicides formulated as disinfectants are used on inanimate surfaces (eg, medical devices); they should not be used on skin or body tissues.
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disinfection a procedure that kills pathogenic microorganisms but not necessarily their spores Project: GP05 NOTE: Chemical germicides formulated as disinfectants are used on inanimate surfaces (eg, medical devices); they should not be used on skin or body tissues.
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disinfection process to eliminate most pathogenic microorganisms without necessarily killing or removing all organisms (eg, bacterial spores) (modified from ISO 15190) Project: M29, POCT13 NOTE 1: A process that reduces or completely eliminates all pathogenic microorganisms, except spores; NOTE 2: Chemical germicides that are formulated as disinfectants are used on inanimate surfaces (medical devices, etc.) and should not be used on skin or tissues; NOTE 3: See disinfectant.
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disk in microbiological testing, a filter paper wafer containing a defined concentration of an antimicrobial agent for use in a disk-agar diffusion antimicrobial susceptibility test Project: VET03
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disk diffusion an in vitro antimicrobial susceptibility test conducted using disks impregnated with a specified single concentration of an antimicrobial agent applied to the surface of an agar medium that has been inoculated with the test organism Project: M02 Source: Microbiology Glossary NOTE: The diameter of the zone of growth inhibition that results from the diffusion of an antimicrobial agent from the disks is measured with calipers or a ruler, recorded in millimeters, and interpreted according to CLSI standards.
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displaying measuring instrument indicating measuring instrument where the output signal is presented in visual form (JCGM 200:2012) Project: ISO IEC Guide 99
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disposal the process of eliminating or deleting a record, beyond any possible reconstruction Project: QMS26 NOTE: Also known as destruction.
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disposal act of indefinitely sequestering either treated or untreated waste, such as by burial in a landfill or waste pile Project: GP05 NOTE: Indiscriminate release to the environment is also considered disposal.
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disruption complete breakage of cell walls and plasma membranes of solid tissues and cells, which is absolutely necessary to release all the DNA and RNA contained in the specimen and to release and inactivate endogenous nucleases Project: MM13 NOTE 1: Different specimen types (eg, tumor tissues vs peripheral blood mononuclear cells) require different methods to achieve complete disruption; NOTE 2: Incomplete disruption results in significantly reduced nucleic acid yields.
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distal remote; farther from any point of reference (Dorland's Illustrated Medical Dictionary. 33rd ed. Elsevier, Inc.; 2019) Project: PRE02 EXAMPLE: The wrist is distal to the elbow.
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distal deep vein thrombosis refers to intravenous thrombosis in a lower extremity affecting the veins distal to the popliteal fossa Project: H59
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distillation a purification process that uses changing the phase of a substance from liquid to vapor and back to liquid, usually at the boiling temperature of the substance, in order to separate it from other substances with higher or lower boiling points Project: GP40
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distribution the frequency of occurrence of an item or value in each segment of categories over a range of categories Project: NRSCL08 NOTE: For data or relationships involving the two variables, frequency and value, the pattern of data is graphically plotted as a function of the values (x-axis) versus the frequency that value is obtained (y-axis).
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distribution-free (statistical procedure) one that does not presuppose that the data arise from a distribution of a particular kind, such as the normal (gaussian) family of distributions Project: EP24 NOTE 1: A near-synonym is “nonparametric”; NOTE 2: For example, drawing a histogram is a simple distribution-free operation, as is any “local” maneuver aimed at smoothing the histogram or smoothing a trend. Any procedure exclusively based on an ordering (ranking) of observations, rather than on their numerical values, is also distribution-free; NOTE 3: “Distribution-free” does not mean “assumption-free.” Assumptions of representative (fair) sampling and independence (independent observations), for instance, are universal.
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distributor person or legal entity that furthers the marketing and/or selling of a device from the original place of manufacture to the ultimate user without modifying the device, its packaging, or its labelling (ISO 18113) Project: ISO 18113-1, ISO 18113-2, ISO 18113-3, M50 NOTE: Adapted from US Code of Federal Regulations (CFR), Title 21, Part 803 — Medical Device Reporting Regulation], 803.3 (g) (ISO 18113-1).
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diversity differences observed between individual gene section sequences derived from several species of a genus (interspecies diversity) and from isolates belonging to the same species (intraspecies diversity) Project: MM18 NOTE: Also often referred to as “variability.”
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DNA amplification failure as used in NBS06, the failure to identify T-cell receptor excision circles or a reference gene sequence due to inadequate amplification of the selected DNA segment(s) Project: NBS06
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DOA drugs of abuse Project: C52
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docking site 1) the location of the physical interface between two components of a system; 2) in Automation, the interface between the transportation system and the instrument and/or the specimen processing and handling devices where the specimen container arrives for sampling to occur Project: AUTO01, AUTO02
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docking station a mechanical and electrical interface that supports the use of a point-of-care device, typically employing legacy mechanical interfaces, connectors, protocols, and power delivery methods Project: POCT01
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docking station equipment designed to physically connect and interface a point-of-care testing device, including all of the wiring, cables, ports, connections, power supply, and communication formats and protocols Project: POCT02
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document (verb) the action of creating a record Project: I/LA33, QMS26 Source: Quality Glossary
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document (noun) information and the medium on which it is contained (ISO 9000) Project: QMS06, GP26, QMS02, QMS16, QMS26, QMS21, QMS25, QMS01 Source: Quality Glossary NOTE: Documents may be paper based or electronic.
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document (noun) any recorded item of a factual or informative nature, either paper or electronic; written or electronically generated information and work instructions Project: I/LA33 NOTE: Examples of documents include quality manuals, procedures, or forms.
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document control coordinator person responsible for managing document creation, review, editing, and distribution Project: QMS02
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dominant describes a trait or disorder in which the phenotype is expressed in those who have inherited only one copy of a particular gene variant Project: MM19
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donor specimen a urine specimen collected from a subject for the purpose of forensic testing Alternate Term: drug donor specimen Project: C52 NOTE: The term "e;donor"e; is used in contrast to "e;patient"e; to distinguish forensic from clinical testing.
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donor surrogate a cell that has the same mismatched antigens that occurred with the donor Project: ILA29
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donor-specific antibody (DSA) antibody formed in the recipient that is directed against the mismatched HLA antigens found in the donor Project: ILA29
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dose-response curve a graphical representation of the relationship between the amount (dose) of a pharmacologically active agent administered to organisms and either the number or percentage of organisms that show a response Project: NRSCL08
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dot plot two-dimensional representation of flow data; each dot represents an individual cell or event Project: ILA29 NOTE: A scatter plot shows forward scatter (cell size) on the x-axis and side scatter (cell internal complexity) on the y-axis. A fluorescence dot plot shows one color on the x-axis (eg, fluorescein isothiocyanate [FITC]) and another color (eg, phycoerythrin) on the y-axis, with each color linked to a cell marker of interest. Fluorescence dot plots are divided into four quadrants: double negative cells or events, double positive, single positive along x-axis, and single positive along y-axis.
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double-voided specimen a urine specimen that is collected together with a blood specimen (within n minutes) to compare the concentration of an analyte (eg, glucose) in these body fluids at that time Project: GP08
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downdraft movement of air through exhaust vents located near the floor to take airborne particulates or chemical fumes that are heavier than air out of a space Project: QMS04
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download data transmitted from an information system to a clinical instrument Project: LIS02
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draft a rough or preliminary piece of writing Project: QMS02
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drainage bag a container that collects urine passed through a urinary catheter, to which it is connected through the catheter tubing Project: PRE05 NOTE 1: Also referred to as a urine ostomy bag; NOTE 2: Bags connected to a nephrostomy tube instead of a catheter are called nephrostomy bags.
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drainage fluid fluid that drains through the skin from a surgical site, wound, or other penetrating injury Project: C49 NOTE 1: The medical need is typically to determine whether the fluid is produced locally at the cutaneous site or whether it derives from deeper organ injury (eg, kidney and urinary tract, liver and gall bladder, pancreas, intestine, stomach, esophagus); NOTE 2: Quantitation of organ-specific analytes in a drainage fluid can often provide unique diagnostic information to indicate what organs might need surgical repair.
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draw quantity of blood drawn into the venous blood collection tube from a venipuncture Project: GP39, GP34 NOTE: For testing purposes, the conditions are defined as follows: 101 kPa (760 mm Hg) pressure and 20°C ambient temperature. The temperature of the blood collected is assumed to be 37°C.
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dried blood spot a specimen collected for laboratory testing, using an approved medical device composed of a specified filter paper, on which printed circles indicate the area to be filled with whole blood and air-dried for transport or storage Project: NBS03, NBS02, NBS01, NBS07, NBS04, NBS09, NBS08, NBS05, NBS10 Source: Newborn Screening Glossary NOTE 1: Specimens collected using an approved medical device should yield a reproducible volume of blood per spot (typically 75 to 100 µL for a 12.5-mm circle, 35 to 50 µL for a 10-mm circle); NOTE 2: In newborn screening, the dried blood spot specimen is ideally collected directly from a heelstick using no anticoagulant agents, because anticoagulant agents, particularly heparin and EDTA, interfere with certain assays.
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dried blood spot a cellulose-based medium onto which drops of blood have been applied and dried Project: C50 NOTE: The cellulose is manufactured in such a manner that the volume of blood applied meets a specific standard.
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dried blood spot a specimen collected for laboratory testing using an approved medical device (eg, by the US Food and Drug Administration) comprising a specified filter paper on which printed circles indicate the area to be filled with whole blood. Typically, a specimen of approximately 75 µL of whole blood is applied to a 12–13 mm diameter spot printed on the filter paper and air-dried for transport or storage Project: NBS06 NOTE: In newborn screening, the dried blood spot is ideally collected directly from a heelstick using no anticoagulants. Anticoagulants, particularly heparin and EDTA, have been shown to interfere with certain assays.
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drift a slow, {systematic}change of a metrological characteristic of a measuring instrument {or system, from the start to completion of a set of replicate measurements}(VIM93-5.16)
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drift characteristic slow change of a metrological of a measuring instrument (VIM93)
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drill See exercise Alternate Term: exercise; game Project: GP36
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driver mutation (to include variant and oncogene) changes in the DNA sequence of genes because of variants, or oncogenes that cause cells to become cancerous and grow and spread in the body Project: MM26 NOTE: Detecting driver mutations in tumor specimens can inform treatment plans to stop cancer cells from growing, including using drugs that target a specific mutation
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droplet nuclei the small residues that result from evaporation of fluid from droplets emitted by an infectious host, or created by an atomizing device, or accidentally in microbiology laboratories, autopsy rooms, etc. Project: M29 NOTE: Droplet nuclei are generally less than or equal to 5 µm in size and can remain suspended in air for extended periods of time.
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droplet precautions applies to patients with known or suspected to have serious illnesses transmitted by large particle droplets (greater than 5 µm in size)
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droplets particles of moisture produced by aerosolization that may carry an infectious agent Project: M29 NOTE 1: Droplets larger than 150 µm generally fall to a surface; NOTE 2: Droplets smaller than 150 µm generally evaporate and may remain suspended in air.
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drug any substance that, when absorbed into a living organism, may modify one or more of its functions Project: C43
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drug a substance used to treat an illness, relieve a symptom, or modify a chemical process in the body for a specific purpose Project: I/LA34
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drug effect term commonly used to describe the physiological influence of a drug on the in vivo concentration of a substance, as opposed to an in vitro effect on the analytical process Project: EP07
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drug of abuse drug used for a nontherapeutic purpose Project: C43
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dry chemistry analysis analysis that uses a test strip or reaction cartridge with no liquid reagent requirement and no liquid waste Project: POCT07
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dual-parameter display a graphical representation of data in which correlated values for two different parameters measured on the same cell are plotted on an x,y grid Alternate Term: dot plot, contour plot, cytogram, two-parameter histogram Project: H43, H42, H52 NOTE: This representation of data may also be known as dot plot, contour plot, cytogram, or two-parameter histogram.
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dual-platform method a method for the determination of absolute cell concentration using data derived both from flow cytometric measurements and a second instrument, generally a hematology analyzer Project: H43, H42 NOTE: The flow cytometer is used to obtain the fraction of the cellular subpopulation of interest present within a more abundant parent cell population, usually either total lymphocytes or total white blood cells. The absolute concentration of the parent population is provided by an independent assay of the sample on a second instrument. The product of these two measurements gives the absolute concentration of the population of interest. The disadvantage of the method is a compounding of the error inherent in each of the two measurements, and for this reason is judged inferior to single-platform methodologies.
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Duchenne muscular dystrophy a severe, progressive form of muscular dystrophy (progressive wasting of muscles) that appears in early childhood and affects leg muscles before arm muscles and the proximal limb muscles before the distal ones Project: MM17 NOTE: It is inherited as an X-linked recessive trait and characterized by an absence or decrease in the amount of the protein dystrophin.
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ducts metal pipes for the distribution of air Project: QMS04
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duodenum the proximal portion of the small intestine (Strongyloides stercoralis, Giardia lamblia) Project: M28 NOTE: Although some individuals have changed the species designation for the genus Giardia to G. intestinalis or G. duodenalis, there is no general agreement. Therefore, for this listing, we will retain the name Giardia lamblia.
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duplicate read in next-generation sequencing, independent reads that are identical in nature and are typically removed to avoid biasing determination of allele frequencies Project: MM09 NOTE: In metagenomics, “duplicate reads” typically refers to identical or nearly identical sequences that, because of artifacts in the sequencing process, appear present in numbers greatly exceeding expectations based on chance and that can produce an overestimation of the relative presence of taxa, genes, and function.
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duplication the execution of a treatment more than once under similar conditions (ISO 3534-3-1.11) Project: ISO 3534 NOTE 1: Duplication, as contrasted with replication, refers to a single element of an experiment; NOTE 2: Duplication usually involves a fresh experimental unit, such as a new sample or, when a single unit is involved, an independent retesting of the levels of the factors being studied on that unit (ISO 3534-3-1.11).
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duplication amplification of any region of DNA Project: MM19 NOTE: If an entire gene is duplicated, the second copy of the gene is often free from selective pressure (ie, variants within may have no deleterious effects to its host organism). Thus, the duplicated gene accumulates variants faster than a functional single-copy gene, over generations of organisms.
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duty cycle (magnetron cycling) Microwave power can be applied continuously but is usually pulsed. The power output of the magnetron is controlled by “cycling” the magnetron on and off at full power for some fraction of time to obtain an average power level. The duty cycle of a magnetron is the time the magnetron is ‘on’ divided by the total time of the cycling period Project: GP28 NOTE: Domestic microwave devices have relatively long cycling periods based on intervals of 1/6 min. (10 seconds) and longer, as compared to laboratory analytical grade microwave equipment, which has cycling periods of 1/60 min. (1 second), making heat control more difficult in household microwave devices.
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duty cycle proportion of time during which a device or system is usefully operated. For mass spectrometry, the part of ions of a particular m/z over which the mass analyzer can measure ions. It is expressed in Th, or in µ for an ion carrying an elementary charge, ie, z = 1 Project: C62
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duty cycle fraction of an operational cycle for which signals can be measured Project: C64
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dwell time the amount of time a mass analyzer monitors ions of a particular m/z Project: NBS04
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dwell time the amount of time the mass spectrometer is focused on and attracting ions of a particular mass Project: C50
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dye colored organic compound that, when dissolved in a suitable solvent, can impart colour to a material Project: ISO 19001 NOTE: The physical origin of colour is the selective absorbance (and/or emission) in the visible region of the electromagnetic spectrum between 400 nm and 800 nm. Dyes are molecules with large systems of delocalized electrons (conjugated p electronic system). The light absorbance characteristics of dyes are displayed by absorbance spectra, resulting from plotting absorbance of light against wavelength. The shape of the spectra and the wavelength at maximum absorbance depend on the chemical structure of the dye, the solvent, and on the conditions of the spectral measurements.
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dye intercalation the reversible inclusion of a dye between the molecules of either DNA or RNA NOTE: These dyes, eg, ethidium bromide, may be used to visualize nucleic acid on an electrophoretic gel.
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dynamic range the total span over which an analysis can provide results Project: I/LA18, I/LA23, VET03 NOTE 1: Analytically, the functional range of an assay over which concentrations of an analyte can be measured with accuracy and precision; NOTE 2: Physiologically, the full range of analyte levels to be expected in patient samples.
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dysHb See dyshemoglobin Project: POCT11
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dyshemoglobin a hemoglobin form that is not functionally capable of reversible physicochemical association with oxygen Alternate Term: dysHb Project: POCT11 NOTE: The known dyshemoglobins affecting pulse oximetry are carboxyhemoglobin (COHb), methemoglobin (MetHb), and sulfhemoglobin (SulfHb).
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dysplasia precancerous cellular changes in the cervix that include a spectrum of cellular abnormalities, described as mild, moderate, and severe or marked dysplasia Project: GP15 NOTE: Dysplasia terminology has been replaced with Bethesda terminology for Pap tests; however, it is still used for histologic specimens in many laboratories.
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D-zone test a disk diffusion test using 15-µg erythromycin and 2-µg clindamycin disks spaced 15 to 26 mm apart for Staphylococcus spp. and 12 mm apart for Streptococcus pneumoniae and β-hemolytic Streptococcus spp. to detect the presence of inducible clindamycin resistance Project: M02 Source: Microbiology Glossary
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D-zone test a disk diffusion test using clindamycin and erythromycin disks placed in close proximity to detect the presence of inducible lincosamide (clindamycin, lincomycin, pirlimycin) resistance in staphylococci and streptococci Project: VET01
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E0 the baseline effect when there is no drug present (eg, drug concentration is zero), based on pharmacokinetic/pharmacodynamic modeling Project: M23
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EBV transformed cell lines infection of cells with Epstein Barr virus and subsequent integration of viral DNA into the host genome, resulting in continued expression of viral genes and transformation of the cells Project: ILA29 NOTE: Phenotypic consequences of virally transformed cells include high saturation density, anchorage independent growth, loss of contact inhibition and oriented growth, cytoskeletal disruption, and immortalization.
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EC50 the concentration of drug at which half (50%) of the Emax is achieved, based on pharmacokinetic/pharmacodynamic modeling Project: M23
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echogenic bowel when the fetal bowel displays an echogenicity or brightness equal to or greater than that of surrounding fetal bone, typically the iliac wing, or when there are dilated fetal bowel loops, both of which are associated with an increased risk of cystic fibrosis
Alternate Term: dilated bowel Project: NBS05
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eclipse period the interval between infection with HIV and first detection of viral nucleic acid in plasma using a nucleic acid test with a low detection limit Project: M53
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ectoparasite a parasite living on the exterior of another being Project: POCT10 NOTE: Examples include lice, scabies, chiggers, and dermatophytes.
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EDTA-modified carbapenem inactivation method assay used to differentiate metallo-β-lactamases from serine carbapenemases in Enterobacterales isolates that are positive for the modified carbapenem inactivation method Project: M02, M07 Source: Microbiology Glossary
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education the act or process of imparting or acquiring knowledge, developing the powers of reasoning and judgment, and generally preparing oneself or others intellectually Project: QMS16
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effective F/P ratio the fluorescence yield of a fluorochrome-ligand conjugate (FLC) expressed as moles of equivalent soluble fluorochrome per mole of FLC (in solutions), or as molecules of equivalent soluble fluorochrome (MESF) per molecule of FLC (on stained particles) Project: I/LA24 NOTE 1: The word "ratio" is optional since it is implied by the term "F/P"; NOTE 2: The term "F/P" originally meant "fluorochrome to protein" ratio when it was applied to molar quantities of fluorochrome conjugated to the carrier protein. Since most ligands used in QFC are proteins, the term has been retained. However, FLC reagents often contain an excess of carrier protein for stability, and carrier protein should not be included in determining either molar or effective F/P ratios. For that reason, "F/P" is sometimes taken to mean "fluorochrome to probe" ratio, where the term "probe" implies an active species such as the ligand of a receptor, whether or not it is protein.
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effectiveness extent to which planned activities are realized and planned results are achieved (ISO 9000) Project: GP26, QMS06, QMS14, QMS12, QMS01 Source: Quality Glossary
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efficacy the ability of a medical device to achieve the expected result in attaining diagnosis or treatment, such as the ability of a cardiac defibrillator to revert fibrillation (ISO Guide 63- 2.4). Project: QMS06
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efficiency a statistical parameter that defines the percentage (number fraction multiplied by 100) of results that are true results as measured by an analytical method Project: I/LA20
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efficiency the degree to which a system or component performs its designated functions with minimum consumption of resources Project: AUTO08
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efficiency relationship between the result achieved and the resources used (ISO 9000) Project: QMS14, QMS12
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efficiency (of immunoassays) the percentage (number fraction multiplied by 100) of results that are true results, whether positive or negative Alternate Term: agreement Project: ILA18, I/LA23, H20
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effluent outflow or discharge of liquid waste, as from a sewage system, factory, or nuclear plant Project: GP17
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electrodeionization technology combining ion-exchange resins and ion-selective membranes with direct current to remove ionic impurities from water and maintain the resin in regenerated condition Project: GP40
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electrometer a device that conditions (ie, amplifies) a signal from a sensor and prepares it for collection and processing Project: C39
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electron ionization ionization of an atom or molecule by electrons that are typically accelerated to energies between 10 and 150 electron volts in order to remove one or more electrons from the molecule (IUPAC 2006) Project: C43, C50 NOTE 1: Electrons and photons do not affect molecules or atoms. They interact with them in ways that result in various electronic excitations including ionization. For that reason, it is recommended that the terms “electron impact” and “photon impact” be avoided; NOTE 2: This term should be used instead of electron impact, because electrons and photons do not “impact” molecules or atoms, but interact with them in ways that result in various electronic excitations, including ionization.
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electronic algorithm testing testing by electronic means that does not involve a physical sample, usually using a software program that simulates an actual instrument, producing realistic values and comprehensive flags and errors, that represent the instrument output in the scenario being tested. Alternate Term: dry testing, simulation Project: AUTO15
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electronic control control procedure or algorithm that checks the electronics, software, or other components or procedures of a diagnostic measuring system via electronic circuits or software logic Project: EP23
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electronic data interchange the interface protocols and message formats required to exchange data between information systems or computers Alternate Term: EDI Project: POCT02 NOTE 1: The acronym is general (applying to all such exchange protocols and languages); however, in some industries it has come to refer to specific implementations; NOTE 2: In the point-of-care domain, this term is occasionally used to refer to the specific interface found among point-of-care data management systems, laboratory information systems, clinical information systems, and other systems that serve as the final repository of point-of-care results.
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electronic data interchange a term used in many industries to describe protocols to exchange data between enterprise-class information systems Project: POCT01 NOTE 1: The acronym is general (applying to all such exchange protocols and languages); however, in some industries it has come to refer to specific implementations; NOTE 2: In the point-of-care domain, this term is occasionally used to refer to the specific interface found between point-of-care data management systems, laboratory information systems, clinical information systems, and other systems that serve as the final repository of point-of-care results.
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electronic health record the systemized collection of electronically stored patient health information in a digital format that is maintained by a provider, hospital, and/or health care system over time Project: M39, MM26 NOTE: Automated access to these health records enables sharing across different health care settings and has the potential to streamline the clinician’s workflow.
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electronic medical record a computerized patient medical history Alternate Term: EMR Project: POCT02, POCT07 NOTE: Hospitals are converting older paper copies of records with handwritten physician and nursing notes to computerized records that can store and transfer data in a standardized fashion.
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electronic records management system electronic system in which records are collected, organized, and categorized to facilitate their preservation, retrieval, use, and disposition Project: QMS26
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electropherogram a representation of that which is created during electrophoresis Project: MM10 NOTE: In the process of running a sequencing gel, the profile of the different colored fluorescent dyes, which is seen by the laser as the various oligonucleotides pass by, is interpreted by sequencing analysis software and an electropherogram of colored peaks is created.
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electropherogram the representation of DNA sequence as a plot of fluorescence units over time characterizing the signal strength, noise, base spacing, and base calls generated by the sequencing software Project: MM18, MM24 NOTE: The data are a series of colored peaks where each peak represents one of the four different DNA bases.
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electrophoresis a method of separating large molecules (such as DNA fragments or proteins) from a mixture of similar molecules under the influence of an electric current NOTE: Each kind of molecule travels through the medium at a different rate, depending on its electrical charge and size.
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electrophoresis a laboratory technique used to separate mixtures of ionic solutes by the differences in the rates of migration in an applied electric field Project: NRSCL8, MM10, MM17, MM24
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electrospray ionization an ionization technique that enables mass spectrometric analysis of labile and/or polar compounds Project: NBS04, NBS09 NOTE 1: The solution to be analyzed is sprayed through a capillary into a strong electric field creating fine droplets that evaporate (heated nitrogen drying gas assists the desolvation process), causing gas phase ions to be formed; NOTE 2: Because electrospray is a soft ionization technique, it produces little fragmentation of analyte molecules.
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electrostatic (energy) analyzer a device consisting of conducting parallel plates, concentric cylinders, or concentric spheres that separates charged particles according to their ratio of translational energy to charge by means of a voltage difference applied between the pair (IUPAC 2006) Project: C43
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electrostatic analyzer an energy-focusing device for producing an electrostatic field perpendicular to the direction of ion travel Project: C50 NOTE 1: Usually used in combination with a magnetic analyzer for double-focusing mass analysis; NOTE 2: The effect is to bring to a common focus all ions of a given kinetic energy (or more specifically, energy/charge).
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elevations graphic illustration of the vertical elements of a design, including casework and millwork Project: QMS04
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eligible population the subset of the target population identified by an investigator who may be invited to participate in a prospective observational or experimental study design, or whose medical records will be identified by the investigator for review in a retrospective observational study design Project: GP45 NOTE 1: The eligible population should be representative of the target population about which the investigator intends to make valid inferences about the truth of the study hypotheses; NOTE 2: Persons in the target population may not be eligible for a study because of ethical considerations of the risks in relation to benefits of participation in the study, study design issues related to efficiency, such as restricting the study to persons with more severe disease who are more likely to respond to interventions, or less likely to be lost to follow-up; NOTE 3: Inferences about the target population made from the study findings in the eligible and enrolled population are suspect if the eligible and enrolled populations differ from the target population.
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ELISA an abbreviation for enzyme-linked immunosorbent assay, a ligand binding assay in which a binding molecule (often an antibody or antigen) is attached to a solid-phase surface such as a microtiter plate well, and the extent of binding is determined by the enzymatic activity of an enzyme-conjugated ligand bound to the solid-phase surface from the solution phase Project: I/LA02, ILA29 NOTE 1: ELISA has become a term used generally to refer to solid-phase immunoassays, especially those conducted in microtiter plates, even if the label on the conjugate is not an enzyme; NOTE 2: Other platforms used for solid-phase ligand-binding assays include microbeads, sometimes called “suspension arrays,” and slide-based protein microarrays.
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Emax the maximum possible effect (of the drug), based on pharmacokinetic/pharmacodynamic modeling Project: M23
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emergency a sudden and unforeseen event that calls for immediate measures to minimize its adverse consequences Project: POCT16 NOTE: Emergencies refer to situations in which local resources are adequate to manage the crisis.
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emergency management the organization and management of resources and responsibilities for addressing all aspects of emergencies, in particular, preparedness, response, and initial recovery steps Project: POCT16
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emergency management agency agency responsible for coordinating response to any type of emergency within its jurisdiction; county, state, or national Project: GP36
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emergency operations center community, county, or state command center which, when activated, centralizes and protects leadership responsible for coordinating a disaster response Project: GP36
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emergency operations plan facility, community, county, state, or national plan describing preparedness plans Project: GP36 NOTE: The community plan is often referred to as local emergency operations plan.
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emergency power back-up power system used in case of a public system outage Project: QMS04
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emergency shower see flood shower Alternate Term: flood shower
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emission spectrum the representation of the variation in the intensity of emitted radiation as a function of the wavelength or frequency of the emitted radiation
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empirical therapy treatment initiated before determining the diagnosis of infection in a patient and/or before a specific etiological agent is identified and/or characterized as related to an infectious disease Project: M39
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employee an individual who agrees to work for an individual or entity (employer), is hired by the employer, fulfills the job requirements, works the specific job and hours, and is paid for the performance of the job completed for the employer Project: QMS16 NOTE: An employee is a member of the personnel of the organization.
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employer a person or entity that hires an individual to work for that person or entity for an agreed upon salary, which may be either hourly or a fixed salary for a specific period of working time Project: QMS16
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empyema fluid the presence of pus in a body cavity; usually refers to pus in the pleural cavity Project: H56
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en a printer’s term. An “en” is one-half the width of an “em.” Readers desiring more detailed information are referred to Wikipedia or a typesetting manual Project: AUTO12
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Encapsulating Security Payload an Internet IPsec protocol designed to provide a mix of security services—especially data confidentiality service—in the Internet Protocol (RFC 2828) Project: AUTO09
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encoded content data that has been converted into a machine-readable format, such as a bar code symbology Project: AUTO14
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encoding 1) a system of assigning numeric values to characters; 2) a means of producing a unique combination of bits (a code) in response to an analog signal (IEEE-1007) Project: AUTO01, AUTO02, AUTO03
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encryption cryptographic transformation of data (called “plaintext”) into a form (called “ciphertext”) that conceals the data’s original meaning to prevent it from being known or used. If the transformation is reversible, the corresponding reversal process is called “decryption,” which is a transformation that restores encrypted data to its original state (RFC 2828) Project: AUTO09
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end user personnel in the health care facility familiar with the medical device and its operation Project: H57
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endemic restricted to a particular geographic region Project: M54
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endogenous control endogenous controls are used in gene expression studies to normalize gene expression values in the total RNA relative to expression levels of genes whose expression levels are invariant in a given tissue or tissues Project: MM16 NOTE: Endogenous controls are not within the scope of this guideline.
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endogenous interferent physiologically occurring substance in a specimen (eg, bilirubin or hemoglobin) that causes interference with the analysis of another substance Project: EP07
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endoscopy procedure in which an instrument is used for examination of the interior of a canal or hollow organ Project: GP20, MM17
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endospore a spore produced within a spherule Project: M54
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endotoxin a thermostable lipopolysaccharide component from the cell wall of viable or nonviable gram-negative microorganisms Project: GP40
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end-point immunoassay an immunoassay where the signal is measured when the antigen antibody reaction has reached effective equilibrium and when any nonspecific component of the signal is assumed to be small and constant
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end-point polymerase chain reaction See polymerase chain reaction Project: NBS06
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end-user in vitro diagnostic medical device calibrator calibration material provided to the customer for use with a specific in vitro diagnostic medical device Project: EP32 NOTE: In CLSI EP32, the abbreviated term “end-user calibrator” is sometimes used synonymously with the full term end-user in vitro diagnostic medical device calibrator.
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end-user laboratory in the context of CLSI EP45, end-user laboratory refers to the laboratory that is verifying and implementing a reference interval that may have been established elsewhere Project: EP45
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engineering controls facilities, equipment, or processes designed to isolate, enclose, or remove the hazard in order to prevent exposure in the workplace Project: M29 EXAMPLES: Heating, ventilation, and air conditioning systems with directional airflow; biological safety cabinets; centrifuge safety cups; sharps disposal containers; self-sheathing needles; safer medical devices such as sharps with engineered sharps injury protections and needleless systems.
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engineering controls controls that isolate, minimize, or remove the blood-borne pathogens hazard from the workplace Project: X03 NOTE: That is, safer medical devices, such as sharps with engineered sharps injury protection and needleless systems as well as other medical devices designed to reduce the risk of percutaneous exposure to blood-borne pathogens. Examples include blunt suture needles and plastic or mylar-wrapped glass capillary tubes, as well as controls that are not medical devices, such as sharps disposal containers and biosafety cabinets.
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enhanced antibiogram an antibiogram for which the data are extracted, stratified, and displayed to answer specific questions or to help guide empirical antimicrobial therapy in select patient populations Project: M39 NOTE 1: Data are generally stratified by one or more variables including patient location, type of infection, specimen type, patient comorbidities (eg, cystic fibrosis, burn), patient age, and resistance phenotype (eg, methicillin [oxacillin]-resistant Staphylococcus aureus, carbapenem-resistant Enterobacterales); NOTE 2: Also known as customized antibiogram or specialty antibiogram.
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enhancement the use of a reagent that nonspecifically increases signal in an assay (e.g., the use of polyethylene glycol to increase the rate of formation of antigen-antibody complexes) Project: I/LA18
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ENQ ASCII character denoting the word “enquiry,” which requests establishment of the communication phase Project: AUTO01, AUTO02, AUTO03 NOTE: Part of the protocols in CLSI documents LIS01 and LIS02.
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enrichment (nucleic acid or cellular) the process of increasing in content or abundance, eg, to increase the abundance of one analyte within a complex mixture of nucleic acids or cellular components by the selective removal of nonanalyte nucleic acids or cell components Project: MM13
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enrichment (nucleic acid or cellular) the process of increasing in content or abundance Project: MM09 EXAMPLE: Increasing the abundance of one measurand within a complex mixture of nucleic acids or cellular components by selectively removing other nonmeasurand nucleic acids or cell components.
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enrichment process undertaken to specifically increase the concentration of an analyte Project: C64
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enrolled population 1) the subset of the eligible and target population who are contacted, invited to participate, and actually give informed consent for participation in the study; 2) the subset of the eligible and target population whose medical records are actually reviewed and from which information is actually obtained and included in the study Project: GP45 NOTE 1: The enrolled population is the achieved sample size; NOTE 2: Inferences about the target population made from the study findings in the eligible and enrolled population are subject to bias if the eligible and enrolled populations differ from the target population.
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enterprise master patient index a cross-reference of patient information that is kept current by rules to identify, match, and update data from multiple source applications Project: GP49
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entity that which can be individually described and considered. (ISO 3534-1/93-2.1) Alternate Term: item Project: ISO 3534
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entropy (thermodynamics) a thermodynamic quantity representing the amount of energy in a system that is no longer available for doing mechanical work Project: GP28
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environmental factors conditions that may affect the analysis that include, but are not limited to, temperature, airflow, humidity, vibration, and altitude Project: POCT07
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environmental factors variables that might affect the performance or efficacy of products (eg, temperature, airflow, humidity, light) Project: EP25
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environmental factors conditions that may affect the analysis that include but are not limited to temperature, airflow, humidity, barometric pressure, light, power supply, vibration, electromagnetic radiation, and water Project: EP23
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enzyme substance that acts as a catalyst in living organisms, regulating the rate at which chemical reactions proceed without itself being altered in the process Project: NBS07 NOTE: See acid α-glucosidase.
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enzyme any of various proteins… originating from living cells and capable of producing certain chemical changes in organic substances by catalytic action (RHUD1.7CD)
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enzyme activation a process by which an increase in enzyme activity is brought about by the addition of coenzymes (organic compounds serving as cosubstrates) or activators (inorganic ions, such as Mg++ or K+) (SDELMT84)
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enzyme activity that function of an enzyme that is assayed by measuring conversion of substrate to product per unit time NOTE 1: Activity can be related to the rate of loss of substrate or rate of appearance of product; NOTE 2: Activity is a measure of the amount of an enzyme in terms of the one property that differentiates it from all other proteins, its specific catalytic activity.
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enzyme conjugate one of the reagents of an immunoassay that has an antigen, analyte, or antibody complexed to an enzyme by a covalent linkage Project: I/LA18, I/LA28
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enzyme immunoassay an immunoassay that uses the catalyzing properties of an enzyme for the detection of an immunological reaction Project: M53
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enzyme inhibition a decrease in enzyme activity Project: DI01 NOTE: This may result from temperature change, substrate depletion, end-product formation, or other causes.
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enzyme system an enzyme (or enzymes) and the necessary substrates and cofactors for an enzyme reaction Project: DI01
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enzyme-linked immunosorbent assay (ELISA) a heterogeneous (requires separation of bound and free) immunoassay in which an analyte is captured by its corresponding antigen or antibody, then detected by an enzyme-conjugated reactant Project: I/LA18, POL1/2, H51
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enzyme-linked immunosorbent assay (ELISA) a ligand binding assay in which a binding molecule (often an antibody or antigen) is attached to a solid-phase surface, commonly a microtiter plate well. The antigen containing fluid is added to the antibody/antigen reaction. The extent of binding is determined by the activity of an enzyme that is conjugated with secondary antibodies that are added to the reaction along with the appropriate substrate. Color or light is used to measure the amount of product Project: H59
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enzyme-linked immunosorbent assay See enzyme immunoassay
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enzyme-linked immunospot a laboratory technique in which the secreted products of a cell are specifically and locally captured on the surface of a filter plate and then detected by an enzyme-conjugated detection cascade, and soluble substrates that give colored, insoluble products Project: I/LA26 NOTE: Originally developed to detect specific antibody-secreting cells, the enzyme-linked immunospot has been adapted to detect secretion of cytokines through the use of antibody pairs that are used in a sandwich format, similar to conventional cytokine enzyme-linked immunosorbent assays.
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eosinophilia abnormal increase in the number of eosinophils found in the blood; often found in helminthic infections, especially with tissue invasion (visceral larval migrans, trichinosis, schistosomiasis, ascariasis, strongyloidiasis); also present with other infection processes, allergic reactions (including drug induced) and with some malignant diseases Project: M28
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EOT ASCII character denoting “end of transmission,” indicating the end of a communication phase Project: AUTO01, AUTO02, AUTO03 NOTE: Part of the protocols in CLSI documents LIS01 and LIS02.
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epidemiological cutoff value the epidemiological cutoff value for each agent is the value obtained by considering the wild-type distribution, the modal minimal inhibitory concentration/minimal effective concentration for each distribution, and the inherent variability of the test. Usually, the epidemiological cutoff value encompasses at least 95% of isolates in the wild-type distribution Project: M51 NOTE: Organisms with acquired resistance mechanisms may be included among those for which the minimal inhibitory concentrations/minimal effective concentrations are higher than the epidemiological cutoff value (for disk testing, those with acquired resistance mechanisms would show a zone diameter smaller than the epidemiological cutoff value).
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epidemiological cutoff value the minimal inhibitory concentration (MIC) or zone diameter value that separates microbial populations into those with and without phenotypically detectable resistance (non-wild-type [NWT] or wild-type [WT], respectively). The ECV defines the highest MIC or smallest zone diameter for the WT population of isolates. Project: M100 EXAMPLE: Interpretive Category | ECVs | MIC, µg/mL | Zone Diameter, mm | Wild-type a | ≤ 4 | ≥ 20 | Non-wild-type | ≥ 8 | ≤ 19 |
a. In the example above, the ECV is 4 μg/mL (MIC) and 20 mm (zone diameter). • wild-type – an interpretive category defined by an ECV that describes the microbial population with no phenotypically detectable mechanisms of resistance or reduced susceptibility for the antimicrobial (antifungal) agent being evaluated. • non-wild-type – an interpretive category defined by an ECV that describes the microbial population with phenotypically detectable mechanisms of resistance and reduced susceptibility for the antimicrobial (antifungal) agent being evaluated.
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epidemiological cutoff value the minimal inhibitory concentration (MIC) or zone diameter value that separates microbial populations into those with and without acquired and/or mutational resistance based on their phenotypes (non-wild-type or wild-type), with the ECV defining the highest MIC or smallest zone diameter for the wild-type population of isolates Project: VET02, VET09 NOTE 1: Epidemiological cutoff value is also sometimes referred to as “ECOFF”; NOTE 2: See interpretive category (for epidemiological cutoff values); NOTE 3: An ECV is a stand-alone value used for the purpose of epidemiology and surveillance and not for clinical application.
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epidemiological cutoff value the minimal inhibitory concentration or zone diameter value that separates microbial populations into those with and without acquired and/or mutational resistance based on their phenotypes (non-wild-type or wild-type), with the epidemiological cutoff value defining the highest minimal inhibitory concentration or smallest zone diameter for the wild-type population of isolates Project: VET01 NOTE 1: Epidemiological cutoff value is sometimes referred to as “ECOFF”; NOTE 2: See interpretive category (for epidemiological cutoff values); NOTE 3: A cutoff value is a stand-alone value used for the purpose of epidemiology and surveillance.
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epidemiological cutoff value the minimal inhibitory concentration (MIC) or zone diameter value that separates microbial populations into those with and without phenotypically detectable resistance (non-wild-type or wild-type, respectively). The ECV defines the highest MIC or smallest zone diameter for the wild-type population of isolates Project: M02, M07 EXAMPLE: Category | Example of Categories for an
ECV of 4 µg/mL and 19 mm | MIC, µg/mL | Zone Diameter, mm | Wild-type | ≤ 4 | ≥ 20 | Non-wild-type | ≥ 8 | ≤ 19 |
• wild-type – an interpretive category defined by an ECV that describes the microbial population with no phenotypically detectable mechanisms of resistance or reduced susceptibility for the antimicrobial agent being evaluated. • non-wild-type – an interpretive category defined by an ECV that describes the microbial population with phenotypically detectable mechanisms of resistance and reduced susceptibility for the antimicrobial agent being evaluated.
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epidemiological cutoff value the minimal inhibitory concentration (MIC)/minimal effective concentration or zone diameter value that separates microbial populations into those with and without acquired and/or mutational resistance based on their phenotypes (non-wild-type or wild-type). The epidemiological cutoff value (ECV) defines the upper limit of susceptibility for the wild-type population of isolates Project: M38 EXAMPLE: | Interpretive Category | ECVs | | MIC, µg/mL | Zone Diameter, mm | | Wild-type | ≤ 4 | ≥ 20 | | Non-wild-type | ≥ 8 | ≤ 19 |
• wild-type – an ECV interpretive category defined by an ECV that describes isolates with no mechanisms of acquired resistance or reduced susceptibility for the antimicrobial agent being evaluated • non-wild-type – an ECV interpretive category defined by an ECV that describes isolates with presumed or known mechanisms of acquired resistance and reduced susceptibility for the antimicrobial agent being evaluated
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epidemiological cutoff value also called wild-type cutoff value, separates bacterial populations on the basis of minimal inhibitory concentration distributions. Epidemiological cutoff values are normally established on the basis of the minimal inhibitory concentration distribution data (phenotype) created from testing isolates derived from geographically diverse laboratory surveys Project: VET05, VET04 NOTE: Epidemiological cutoff values are species specific (unless otherwise stated) and protocol specific, but independent of the rearing conditions and pharmacokinetics of any antibiotic treatment.
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epidemiological cutoff value the minimal inhibitory concentration/minimal effective concentration value that separates fungal populations into those with and without acquired and/or mutational resistance based on their phenotypes (minimal inhibitory concentrations) Project: M57 NOTE: Often referred to as the “epidemiological cutoff” or “ECOFF.”
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epidemiologically related isolates isolates cultured from specimens (eg, patients, fomites, the environment) at a discrete time and place as part of an epidemiological investigation of an outbreak and that are presumed to be related based on the epidemiological data collected during the investigation Project: MM24
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epifluorescence method of fluorescence microscopy in which the excitation light is transmitted through the objective lens onto the specimen, and the fluorescence light is transmitted back through the objective lens to the eyepiece Project: GP40 NOTE: Fluorescence is the immediate emission of electromagnetic radiation, typically visible light, from molecules following absorption of light with a shorter wavelength.
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epithelial cell abnormalities precancerous cellular changes in the cervix that include a spectrum of cellular abnormalities such as atypical squamous cells of undetermined significance, atypical squamous cells—cannot exclude high-grade squamous intraepithelial lesion, atypical glandular cells, low-grade squamous intraepithelial lesion, koilocytosis, human papillomavirus effect, and high-grade squamous intraepithelial lesion, adenocarcinoma in situ, and all varieties of epithelial neoplasms Project: GP15 NOTE: These terms are part of the Bethesda 2001 System nomenclature. The Bethesda System is in current use in the United States and several other countries.
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epitope 1) the minimum molecular structure of the antigenic site that will react with a monoclonal antibody; 2) any site on an antigen molecule at which an antibody can bind; the chemical structure of the site determining the specific combining antibody Alternate Term: Antigenic determinant; determinant Project: ILA18, DI01, I/LA23, H56, I/LA28, I/LA34 NOTE: In the context of immunoglobulin E assays, allergenic epitopes are regions on allergens that bind directly to the immunoglobulin E binding site. They can be detected by monoclonal antibodies to (1) determine the level of allergens of a particular specificity in an environmental specimen (eg, Der p 1 and Der f 1 in house dust); and (2) demonstrate identity and qualify extracts during the manufacturing of allergen-containing reagents.
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epitope (antigenic determinant) that portion of an antigen against which the specific binding region of an antibody is directed Project: M53 NOTE: Epitopes may be linear sequences of as few as six amino acids or conformationally determined sections of the antigen; each antigen typically contains multiple epitopes.
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epitope (antigenic determinant) that portion of an antigen against which the specific binding region of a monoclonal antibody reagent is directed Project: H43, ILA29, H42, H52 NOTE 1: Epitopes may be linear sequences of as few as six amino acids or conformationally determined sections of the antigen; each antigen typically contains multiple epitopes; NOTE 2: Epitopes may be linear sequences of as few as six contiguous amino acids or conformationally determined by spatial organization of peptide domains exposed on a folded protein. Each antigen typically contains multiple epitopes.
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epitope any site on an antigen molecule at which an antibody can bind; the chemical structure of the site determining the specific combining antibody Project: I/LA26
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epitope (determinant) the minimum molecular structure of the antigenic site that will react with a monoclonal antibody; any site on an antigen molecule at which an antibody can bind; the chemical structure of the site determining the specific combining antibody Project: I/LA20 NOTE: In the context of immunoglobulin E assays, allergenic epitopes are regions on allergens that bind directly to the immunoglobulin E antibody binding site. They can be detected by monoclonal antibodies to: 1) determine the level of allergens of a particular specificity in an environmental specimen (eg, Der p 1 and Der f 1 in house dust); and 2) demonstrate identity and qualify extracts during the manufacturing of allergen-containing reagents.
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epoxy paint paint that contains resins to allow more water and chemical resistance Project: QMS04
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epoxy resin a poured, molded, solid material used in laboratory countertops, floors, or other surfaces Project: QMS04
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equipment the articles or implements used or needed for a specific purpose or activity Project: M29
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equipment single apparatus or set of devices or apparatuses needed to perform a specific task (adapted from IEV 151-11-25) Project: QMS13, QMS01 Source: Quality Glossary NOTE 1: For the purpose of QMS13, equipment includes general purpose devices; NOTE 2: For the purpose of QMS01, equipment includes general purpose devices, analytical systems, and computer system hardware and software.
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equipment error a problem with equipment and/or its software used in the performance of a test or storage of samples and/or reagents leading to an unacceptable PT result
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equipment master file paper or electronic file in which records of a given instrument or piece of equipment from acquisition to decommission are maintained Project: QMS13
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equipoise 1) an ethical basis for clinical research in which there is a state of genuine uncertainty on the part of the clinical investigator regarding the comparative therapeutic merits of each arm in a trial; 2) an alternative concept of equipoise is based on present or imminent controversy in the clinical community over the preferred treatment; according to this concept of “clinical equipoise,” the requirement is satisfied if there is genuine uncertainty within the expert medical community—not necessarily on the part of the individual investigator—about the preferred treatment Project: GP45 NOTE: Should the investigator discover that one treatment is of superior therapeutic merit, he or she is ethically obliged to offer that treatment; the current understanding of this requirement, which entails that the investigator have no “treatment preference” throughout the course of the trial, presents nearly insuperable obstacles to the ethical commencement or completion of a controlled trial and may also contribute to the termination of trials because of the failure to enroll enough patients.
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equivalence property of a set of measurement results for a specified measurand, such that the absolute value of the difference of a pair of measured values from two different measurement results is smaller than a chosen limit related to the intended clinical use of the measurement results Project: EP32
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equivalence the condition of being equal or equivalent in value, worth, function, mean, etc. Project: EP35 NOTE: For the purpose of CLSI EP35, equivalence refers to establishing evidence that the clinical parameters or clinical usefulness of results between the primary specimen type and the candidate specimen type are comparable for a given measurement procedure.
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equivalent reference fluorophores unit of fluorescence intensity; the number of reference fluorophores in solution that produce the same fluorescence signal as a single dyed microsphere or bead. The equivalent reference fluorophores value assignment is provided by the National Institute of Standards and Technology and is traceable to National Institute of Standards and Technology SRM® 1934 (or the equivalent) standard reference material Project: H62
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equivocal result a test result, within a specified range of the cutoff value, that cannot be interpreted as either positive or negative Project: MM02, MM10, MM03, MM12, MM17, M55 NOTE: In molecular genetics, equivocal test results may complicate risk interpretations.
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equivocal zone internal continuous response (ICR) interval around the cutoff within which the final result cannot be reported as either positive or negative, but is reported as “equivocal,” with or without including the actual result value Alternate Term: indeterminate zone Project: EP12, EP12-IG NOTE 1: In most cases, an equivocal result triggers follow-up steps for obtaining a binary result; NOTE 2: Many binary examinations include an internal control that can indicate when the ICR is unreliable or an output cannot be reported. An equivocal zone is different than an equivocal result; NOTE 3: Example studies in EP12 assume all binary results are available (ie, no missing or excluded results); NOTE 4: Also known as “gray zone” in the medical laboratory and as “guard band” in chemical metrology.
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ergonomics study of the efficiency of persons in their working environment (ISO 15190) Project: ISO 15190, QMS04 NOTE: This term includes biomechanics, work physiology, anthropomorphism, and man-machine interfaces (ISO 15190).
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ERR an Health Level Seven error segment (HL7 V2.6) Project: AUTO01, AUTO02, AUTO03
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erroneous result a patient result that fails its quality requirement Project: C24 NOTE 1: The quality requirement is usually expressed in terms of an allowable total error requirement. If the measurement error in a patient’s result exceeds the total error requirement, the result is erroneous; NOTE 2: May also be referred to as an incorrect result or an unacceptable result.
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error (measurement) measured quantity value minus a reference quantity value (JCGM 200:2012) Alternate Term: error of measurement; measurement error Project: EP10, JCGM 200:2012, POCT05, H26, GP34, EP06, C58, C51, C56, EP27, MM20, EP26, H60, C62, C57, MM23, POCT06, H48, EP21, C24, EP34, EP46, MM24 NOTE 1: The concept of “measurement error” can be used when there is a single reference quantity value to refer to, which occurs if a calibration is made by means of a measurement standard with a measured quantity value having a negligible measurement uncertainty or if a conventional quantity value is given. In this case, the measurement error is known. The concept also can be used if a measurand is represented by a unique true quantity value or a set of true quantity values of negligible interval. In this case, the measurement error is not known (modified from JCGM 200:2012); NOTE 2: Measurement error should not be confused with production error or mistake (JCGM 200:2012); NOTE 3: The sign of the difference must be noted; NOTE 4: Generally, a known measurement error should be corrected using the best estimate of that measurement error. The measurement uncertainty of a correction is part of the combined measurement uncertainty; NOTE 5: In C56, the “reference quantity value” would be the result from the same measurement procedure on the same sample in the absence of any hemolysis, icterus, or lipemia/turbidity interference; NOTE 6: A reference quantity is intended to be an estimate of the true quantity present in a sample; NOTE 7: For qualitative tests, an erroneous finding of the measurement procedure, eg, the presence of an analyte when the analyte is not present, and vice versa; NOTE 8: A difference between a computed, estimated, or measured value and the accepted true, specified, or theoretically correct value.
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error (systematic [of measurement]) component of measurement error that in replicate measurements remains constant or varies in a predictable manner (JCGM 200:2012) Alternate Term: systematic error of measurement; systematic measurement error Project: ISO IEC Guide 99, C51, EP06, QMS24, C24, EP19 NOTE 1: A reference quantity value for a systematic measurement error is a true quantity value, or a measured quantity value of a measurement standard of negligible measurement uncertainty, or a conventional quantity value (JCGM 200:2012); NOTE 2: Systematic measurement error, and its causes, can be known or unknown. A correction can be applied to compensate for a known systematic measurement error (JCGM 200:2012); NOTE 3: Systematic measurement error equals measurement error minus random measurement error (JCGM 200:2012); NOTE 4: “Measurement bias” is an estimate of “systematic measurement error.” NOTE 5: For qualitative tests, an erroneous finding of the test method, eg, the presence of an analyte when the analyte is not present, and vice versa.
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error (random [of measurement]) component of measurement error that in replicate measurements varies in an unpredictable manner (JCGM 200:2012) Alternate Term: random error of measurement; random measurement error Project: ISO IEC Guide 99, EP06, C51, QMS24, EP19 NOTE 1: A reference quantity value for a random measurement error is the average that would ensue from an infinite number of replicate measurements of the same measurand (JCGM 200:2012); NOTE 2: Random measurement errors of a set of replicate measurements form a distribution that can be summarized by its expectation, which is generally assumed to be zero, and its variance (JCGM 200:2012); NOTE 3: Random measurement error equals measurement error minus systematic measurement error (JCGM 200:2012); NOTE 4: The standard deviation of the random measurement error is sometimes called “imprecision.”
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error (of measurement) result of a measurement minus a true value of the measurand (VIM93) Alternate Term: measurement error; total analytical error Project: I/LA25, H54, MM10, MM12, H20 NOTE 1: Since a true value cannot be determined, in practice a conventional true value is used (VIM93); NOTE 2: When it is necessary to distinguish “error” from “relative error,” the former is sometimes called absolute error of measurement. This should not be confused with absolute value of error, which is the modulus of the error (VIM93); NOTE 3: Formerly, the term “total error” was often used in CLSI documents.
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error a deviation from truth, accuracy, or correctness; a mistake Project: GP26, GP23, QMS11, QMS24 NOTE: Error in the proficiency testing process leads to an unacceptable result. Error in proficiency testing has many subtypes and classifications. Error might be classified as to when it occurred in the proficiency testing process (eg, preexamination error, examination error, or postexamination error). Error might also be classified as to the root cause of the error, as in clerical error or transcription error, equipment error, reagent error, or methodological error.
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error (allowable) the magnitude of analytical deviation, from all sources, that a user can tolerate in a testing system and still meet the medical requirements of the test Alternate Term: allowable error Project: EP06 NOTE: The allowable error boundaries (for a single observation) are represented by the target value of the specimen plus or minus the allowable error amount.
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error 1) a false or mistaken result obtained in a study or experiment; 2) “random error” (sampling error) is that due to chance, when the result obtained in the sample differs from the result that would be obtained if the entire population (“universe”) were studied; 3) “systematic error” is that due to factors other than chance, such as faulty measuring instruments Project: GP45 NOTE 1: It is further considered in bias; NOTE 2: Several kinds of error can occur in epidemiology, for example, due to bias; NOTE 3: Two varieties of sampling error are type I, or alpha error, and type II, or beta error. In an experiment, if the experimental procedure does not in reality have any effect, an apparent difference between experimental and control groups may nevertheless be observed by chance, a phenomenon known as type I error. Another possibility is that the treatment is effective but by chance, the difference is not detected on statistical analysis—type II error; NOTE 4: In the theory of testing hypotheses, rejecting a null hypothesis when it is actually true is called type I error; accepting a null hypothesis when it is incorrect is called type II error.
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error measured quantity value minus a reference quantity value (JCGM 200:2008); deviation from truth, accuracy, or correctness; includes mistakes Project: EP23 NOTE: In EP23™, the term “error” includes but is used in a much broader sense than the VIM term “error of measurement.”
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error grid a scatterplot for comparing measurements obtained from two measurement procedures, eg, a candidate measurement procedure (y-axis) and a comparative measurement procedure (x-axis) Project: EP27 NOTE: The error grid plot includes zones indicating the potential harm associated with measurement errors.
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error of measurement See error Alternate Term: error; measurement error Project: C51
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erythrocyte a red blood cell; the hemoglobin-containing cell of the cells found in peripheral blood Alternate Term: ERC, RBC Project: NRSCL8
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erythrocyte indices quantities derived (calculated) from the measured hemoglobin concentration (Hb), the red blood cell count (RBC), and the packed (red) cell volume (PCV): MCH (mean corpuscular hemoglobin) in picograms (pg), Hb (g/L) divided by RBC (..x 1012/L); MCHC (mean corpuscular hemoglobin concentration) in grams per liter (g/L), Hb (g/L) divided by PCV (L/L); and MCV (mean corpuscular volume) in femtoliters (fL), PCV (L/L) divided by RBC (..x 1012/L) Alternate Term: red cell indices, RBC indices
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esoteric (testing) the analysis of “rare” substances or molecules that are not performed in a routine medical laboratory Project: MM20
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essential agreement (EA) MIC result obtained with the AST device that is within plus or minus one doubling dilution step from the MIC value established with the reference method. Another representation of the concept:NEA × 100/N, where NEA is the number of bacterial isolates with an EA; N is the total number of bacterial isolates tested (ISO 20776-2) Project: ISO 20776-2 NOTE: The overall EA is expressed as a percentage (ISO 20776-2).
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essential agreement minimal inhibitory concentration result obtained with the antimicrobial susceptibility testing system that is within one doubling dilution step (two-fold serial) for bacteria and two doubling dilution steps for yeast from the minimal inhibitory concentration value established with the reference method (modified from ISO 20776-2) Project: M52 NOTE 1: Another representation of the concept: NEA • 100/N where NEA is the number of microbial isolates with an essential agreement; N is the total number of microbial isolates tested (modified from ISO 20776-2); NOTE 2: The overall essential agreement is expressed as a percentage (modified from ISO 20776-2).
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essential efficacy efficacy, where, to be of benefit to a patient, the use of a medical device satisfies certain basic criteria: (i) it must not injure or otherwise harm the patient; (ii) it must perform as intended by the manufacturer; (iii) it must be used properly (ISO Guide 63-2.5)
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essential element an element that (1) a species cannot achieve normal, healthy growth or complete its normal lifecycle without and (2) is part of a molecule of an essential constituent or metabolite Project: C38 NOTE 1: A trace element that is consistently detectable in human tissues or fluids is not necessarily essential. Many trace elements are so ubiquitous in the environment (eg, aluminum, lead) that they are “normally” found in human tissues and fluids. As analytical detection limits are improved further, other rare elements could also be detected at ultratrace levels; NOTE 2: The criteria used to establish essentiality in other areas of life science, eg, plant growth can be adapted, with some qualification, to the animal kingdom; NOTE 3: The element must be specific and not replaceable by another, and it must exert its effect directly on growth or metabolism and not by some indirect effect, such as antagonism of another element present at toxic levels; NOTE 4: A number of trace elements have been clearly identified as essential for normal, healthy growth in humans. While there may be some elements that are not universally accepted because of the paucity of data supporting claims for essentiality, they may be considered borderline candidates.
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establish define, document (in writing or electronically), and implement Project: GP26, QMS01 Source: Quality Glossary
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establish the determination of the performance characteristics of a new or modified measurement procedure Project: EP25
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establishment stage of the Test Life Phases Model; the Establishment Stage includes the design, development, and validation phases performed by the developer resulting in a tangible product Project: EP45
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establishment stage of the Test Life Phases Model; for the purposes of EP19, the Establishment Stage includes the Feasibility and Design, Development, and Validation Phases performed by the developer, resulting in a tangible product Project: EP19
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establishment study in the context of CLSI EP45, a study done to establish a reference interval for a specific analyte following an accepted methodology. Some sources may refer to this study as a validation study Project: EP45
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estimate a specific value (ie, point estimate) or values (ie, interval estimate) of an estimator Project: NRSCL08, C56 NOTE 1: An estimate is calculated from a specific sample or set of observations to produce a specific value or set of values; NOTE 2: Point estimate: a value that summarizes a set of data without accounting for the precision of the estimate (eg, its uncertainty).
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estimator statistic used in estimation of the parameter (ISO 3534-1) Project: ISO 3534-1, C56 NOTE 1: An estimator differs from an estimate in that the estimator is an “equation,” while the estimate is the value of that equation calculated from the sample values; NOTE 2: Estimators have different properties (eg, unbiasedness, consistency, sufficiency, and efficiency) but they do not have the property of “correctness.” Thus, there is no such thing as a correct estimator.
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etched describes a process whereby a resultant bar code is generated by an ablative or reductive process Alternate Term: reductive bar code generation Project: AUTO14 NOTE: An initially confluent dark contrast layer (of polymer, paint, ceramic, etc.) is removed (mechanically, optically, or photochemically), exposing a lighter color beneath. Typically, this process can be observed in marker technologies that generate bar-coded tissue cassettes, microscope slides, and a growing number of specialized, small form-factor molecular diagnostics containers. This process is fundamentally different from the more typical bar code image generation process, in which darker contrast material (eg, ink) is applied or otherwise generated, (eg, by heat) to an initially light background field.
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ethylene diamine tetraacetic acid (EDTA) one of a class of aminopolycarboxylic acids that act as sequestering (also referred to as “chelating”) agents Project: MM02 NOTE 1: They form soluble complexes with metal ions, removing these ions from further reactions (MM02); NOTE 2: They are negatively charged compounds.
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etiologic agent a viable microorganism or its own toxin that causes, or might cause, human infection Project: GP05, QMS28
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etiologic agent the causative agent of a disease (e.g., the microorganism that causes a specific infectious disease) Project: H05
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evaluated method that measurement procedure for general clinical use that is being evaluated for a possible matrix effect
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evaluation analysis of completed or ongoing activities that determines or supports the accountability, effectiveness, and efficiency of an activity or program Project: QMS16, QMS14, QMS03
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evaluation any determination of the clinical or analytical performance characteristics of the test Project: EP19, H57, I/LA28
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evaluation analysis of completed or ongoing activities that determine or support the accountability, effectiveness, and efficiency of an activity or program Project: QMS05
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evaluation (study) a generic term for any investigation that measures the performance capabilities of an assay Project: M52
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evaluation of formed elements an inclusive term encompassing the tabulation of white blood cells in a representative sample of human blood by a standard classification scheme (ie, differential or “diff”), notation of the presence or absence of certain red blood cell abnormalities, and notation of platelet sufficiency and morphology Project: H20
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evaluation plan description of a planned performance evaluation (ISO 20776-2) Project: ISO 20776-2
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evaluation report description of and conclusion from a performance evaluation (ISO 20776-2) Project: ISO 20776-2
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evaluator individual responsible for measurement and assessment of performance, noting unresolved issues, and analysis of exercise results Project: GP36 NOTE 1: Selected from participating agencies, evaluators are chosen based on their expertise in the functional areas they will observe; NOTE 2: Evaluators passively assess and document participants’ performance against established emergency plans and exercise evaluation criteria; NOTE 3: Evaluators only note the actions/decisions of players without interfering with exercise flow.
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event a single particle or cell identified by a flow cytometer Project: H43, H42, H52
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event (proficiency testing) a single round of proficiency testing/external quality assessment testing, which may include more than one challenge (specimen or sample) Project: MM14, QMS24
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event an episode when the true value of the blood glucose, as measured by a stated reference method, goes below a predefined concentration (hypoglycemia) or above a predefined concentration (hyperglycemia)
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event a single unit of measurement detected and counted by flow cytometry, typically an individual cell or particle Project: H62 NOTE: A flow cytometer associates all light signals that occur without a gap in time with a single event and stores the light intensities in association with that event in the data file. If cells (or other particles) are spaced appropriately in the core stream and do not coincide in the laser beam, an event is the same as a cell or particle. If cells coincide in the laser beam, an event may be two or more cells.
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event generic term used to encompass the terms “incident,” “error,” and “accident”
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event of interest See condition of interest
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evidence of compliance documents, records, factual statements, and other verifiable information demonstrating compliance with requirements (modified from ISO 9000) Project: QMS17
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ex vivo a same-day in vitro analysis of biological samples Project: I/LA26
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examination set of operations with the object of determining the value or characteristics of a property (ISO 15189) Project: QMS02, GP26, PRE04, QMS06, QMS11, QMS13, EP12, GP33, POCT07, POCT10, PRE01, GP23, QMS25, EP23, QMS22, QMS01, EP35 Source: Quality Glossary EXAMPLE: A test procedure or measurement procedure; NOTE 1: In some disciplines (eg, microbiology), an examination is the total activity of a number of tests, observations, or measurements (ISO 15189); NOTE 2: In CLSI QMS02, the term “examination” replaces the term “test”; however, for the purposes of this guideline, readers can consider the terms equivalent; NOTE 3: Laboratory examinations that determine a value of a property are called quantitative examinations; those that determine the characteristics of a property are called qualitative examinations (ISO 15189); NOTE 4: In clinical chemistry, laboratory examinations have been called assays or tests (ISO 18113-1); NOTE 5: Examination has replaced terms such as test, assay, and analysis in CLSI POCT07. Subsequently, the adjectives preexamination and postexamination have replaced the adjectives preanalytical and postanalytical; NOTE 6: Laboratory examinations are also often called assays or tests (ISO 15189); NOTE 7: In CLSI EP35, examinations are also called measurement procedures; NOTE 8: In CLSI EP12, laboratory examinations that determine a value of a property are measurement procedures; those that determine the characteristics of a property are called qualitative examinations.
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examination (binary) an examination that produces a binary output Alternate Term: qualitative, binary examination Project: EP12 NOTE 1: Binary examinations can have an internal continuous response that has quantifiable values. However, there is no requirement to characterize these values except in proximity to the cutoff used to provide the binary result; NOTE 2: In EP12, whenever the term “qualitative examination” is used without a modifier, it is assumed to mean qualitative, binary examination.
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examination (nominal) an examination that characterizes a sample into multiple possible unordered categories Project: EP12 EXAMPLE: Blood type.
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examination (ordinal) an examination that characterizes a sample into multiple possible ordered categories Project: EP12 NOTE: Common examples produce outputs such as 0, +, ++, +++, and ++++.
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examination procedure set of operations, described specifically, used in the performance of examinations according to a given method (ISO 15198) Alternate Term: analytical phase Project: ISO 15198, GP26 NOTE: In the IVD medical device industry and in many laboratories that use IVD medical devices, an examination procedure for an analyte in biological sample is commonly referred to as an analytical method, analytical procedure, or test procedure (ISO 15198).
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examination process (analytic) processes that include all activities for performing the examinations, verifying the reliability of the results, and interpreting the findings (ISO 15189)
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excitation the transition of a fluorochrome molecule from its lowest energy state (ie, ground state) to a higher energy state following absorption of incident light (see Appendix A of I/LA24) Project: I/LA24
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excitation spectrum the spectrum of wavelengths at which a fluorescent compound absorbs light, followed by the emission of light at a different wavelength from that of the absorbed light Project: SDELMT84, DI01
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exclusion of venous thromboembolism a claim that can apply to any method, the results of which can reliably exclude venous thromboembolism Project: H59 NOTE 1: Regarding a D-dimer reagent, studies must demonstrate that the negative predictive value, sensitivity, and coefficient of variation at the threshold have sufficient power to exclude venous thromboembolism when the test is applied to patients judged to have a low or intermediate probability of venous thromboembolism determined using a pretest probability scoring algorithm; NOTE 2: As defined by the US Food and Drug Administration, a D-dimer assay with an exclusionary claim is used in conjunction with a pretest probability assessment to exclude the presence of a pulmonary embolism and/or a deep vein thrombosis. In addition to validating the assay’s threshold and establishing assay sensitivity, specificity, and negative predictive values compared with imaging studies, the clinical study must include patient follow-up to obtain clearance.
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exercise instrument to train for, assess, practice, and improve performance in prevention, protection, response, and recovery capabilities in a risk-free environment Alternate Term: game; drill Project: GP36 NOTE 1: Exercises can be used for: testing and validating policies, plans, procedures, training, equipment, and interagency agreements; clarifying and training personnel in roles and responsibilities; improving interagency coordination and communications; identifying gaps in resources; improving individual performance; and identifying opportunities for improvement; NOTE 2: An exercise is also an excellent way to demonstrate community resolve to prepare for disastrous events.
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exhaust air air that is removed from an area Project: QMS04
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exogenous developed or originating outside an organism Project: HS02 NOTE: Caused by external factors.
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exogenous developed or originating outside an organism; caused by external factors Project: POCT10
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exogenous interferent substance originating outside the body (eg, a drug or its metabolites, a specimen preservative, or a sample contaminant) that causes interference with the analysis of another substance in the specimen Project: EP07
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exome all coding regions (ie, exons) present in the genome of an organism or individual Project: MM09 NOTE: During whole-exome sequencing, the protein-coding regions of the genome are targeted for sequencing.
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exon a transcribed region of a gene that is present in the mature messenger RNA Project: MM19, NBS05
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exotoxin a soluble toxin excreted by a microorganism Project: NRSCL08
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expandability the ease with which a system or component can be modified to increase its storage or functional capacity Project: AUTO08
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expanded genetic analysis molecular method applied following the identification of a single variant allele to test for the presence of additional variants Project: NBS05
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expanded measurement uncertainty See expanded uncertainty Alternate Term: expanded uncertainty Project: C51
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expanded measurement uncertainty product of a combined standard measurement uncertainty and a coverage factor k Project: EP32 NOTE 1: The factor depends on the type of probability distribution of the output quantity in a measurement model and the selected coverage probability; NOTE 2: The expanded uncertainty of a quantity y is symbolized Uy or U(y); NOTE 3: The coverage factor should always be specified. If the term “standard uncertainty” or some variation including the word “standard” is used, the coverage factor is 1. If the term “expanded uncertainty” or some variation including the word “expanded” is used, the coverage factor is larger than 1.
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expanded scale scale in which a part of the scale range occupies a scale length that is disproportionately larger than other parts (VIM93)
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expanded uncertainty (measurement) product of a combined standard measurement uncertainty and a factor larger than the number one (JCGM 200:2012) Alternate Term: expanded measurement uncertainty Project: ISO IEC Guide 99, C51, EP30 NOTE 1: The factor depends upon the type of probability distribution of the output quantity in a measurement model and on the selected coverage probability (JCGM 200:2012); NOTE 2: The term “factor” in this definition refers to a coverage factor (JCGM 200:2012); NOTE 3: Expanded measurement uncertainty is termed “overall uncertainty” in paragraph 5 of Recommendation INC-1 (1980) (see the GUM) and simply “uncertainty” in IEC documents (JCGM 200:2012); NOTE 4: An expanded uncertainty is symbolized U; NOTE 5: The expanded uncertainty of a quantity y is symbolized Uy or U(y).
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expected range the range of values for a measurand in a typical healthy population Project: NBS03, NBS05, NBS02, NBS13, NBS01, NBS07, NBS09, NBS10 Source: Newborn Screening Glossary NOTE 1: The expected range is a population distribution, not an analytical parameter, that can be estimated by applying statistical methods to data from reference populations that are representative of the population being tested. The limits of the expected range might vary, depending on the reference population and the statistical methods used; NOTE 2: The expected range for newborn screening results might vary by calendar and gestational age; NOTE 3: For purposes of newborn dried blood spot screening, results within the expected range should exclude the presence of the congenital condition that the test is used to detect, while results outside of the expected range may need to be acted upon; NOTE 4: As used in NBS07, the range of acid α-glucosidase activity values measured in dried blood spot specimens from newborns without Pompe disease, as opposed to laboratory test results that show acid α-glucosidase activity values below the predetermined cutoff (ie, a result outside of the expected range, or an out-of-range result); NOTE 5: The analytically validated calibration range should ideally encompass the population expected range and the range surrounding the value used to distinguish screen-positive and screen-negative results; NOTE 6: Expected ranges may be specified separately for subpopulations such as full-term newborns, preterm and low birth weight newborns, and older infants; NOTE 7: As used in NBS07, the laboratory test result of any satisfactory dried blood spot specimen that shows acid α-glucosidase activity values at or above the predetermined cutoff is a screening result that is out of the expected range requiring follow-up (ie, a laboratory test result outside of the expected range of normal/negative testing results established for a particular condition, including carrier results, that indicates the need for additional testing); NOTE 8: As used in NBS09, the range of C26:0-lysophosphatidylcholine values measured in dried blood spot specimens from newborns without adrenoleukodystrophy disease, as opposed to laboratory test results that show C26:0-lysophosphatidylcholine values above the predetermined cutoff (ie, a result outside of the expected range, or an out-of-range result); NOTE 9: As used in NBS09, the laboratory test result of any satisfactory dried blood spot specimen that shows C26:0-lysophosphatidylcholine values at or above the predetermined cutoff is out of the expected range and requires follow-up; NOTE 10: Also called “reference range” and “normal range,” although the preferred terms are “biological reference interval” or “reference interval”; NOTE 11: See in-range and out-of-range.
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expected range as used in NBS06, the range of T-cell receptor excision circle values in term newborns without severe combined immunodeficiency or other T-cell immunodeficiencies Project: NBS06 NOTE 1: The expected range is a population distribution and not an analytical parameter. The analytically valid calibration range should ideally encompass the population expected range; NOTE 2: As used in NBS06, the laboratory test result of any satisfactory newborn screening specimen that shows T-cell receptor excision circle values at or above the predetermined cutoff. A laboratory test result that is outside of the expected range of normal/negative testing results established for a particular condition (includes carrier results) that indicates the need for further testing; NOTE 3: As used in NBS06, the laboratory test result of any satisfactory newborn screening specimen that shows T-cell receptor excision circle values below the predetermined cutoff would be outside the expected range, or out of range.
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experimental standard deviation for a series of n measurements of the same measurand, the quantity "s" characterizing the dispersion of the results and given by the formula:xi being the result of the i-th measurement and x being the arithmetic mean of the n results considered NOTE 1: A valid statement of reproducibility requires specification of the conditions changed; NOTE 2: The changed conditions may include:principle of measurement, method of measurement, observer, measuring instrument, reference standard, location, conditions of use, and time; NOTE 3: Reproducibility may be expressed quantitatively in terms of the dispersion characteristics of the results; NOTE 4: Results are here usually understood to be corrected results.
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expert system a software system consisting of a knowledge base, inference engine, and explanation unit Project: AUTO08 NOTE: The knowledge base contains rules from experts, the inference engine uses this knowledge to reach conclusions given certain facts, and the explanation unit serves to explain how the conclusions were reached.
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expert system antimicrobial susceptibility testing software that alerts users to atypical susceptibility testing results Project: M52
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expiration date date after which the product, when stored under recommended conditions, should no longer be used Project: GP39, GP34
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expiration date upper limit of the time interval during which the performance characteristics of a material stored under specified conditions can be assured Alternate Term: expiry date NOTE: Expiry dates are assigned to in vitro diagnostic reagents, calibrators, control materials, and other components by the manufacturer based on experimentally determined stability properties (adapted from EN 375:2001, §3.6).
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expiry date upper limit of the time interval during which the performance characteristics of a material stored under specified conditions can be assured (ISO 18113-1) Alternate Term: expiration date Project: ISO 18113-1, ISO 18113-2, ISO 18113-3, EP25 NOTE 1: Expiry dates are assigned to IVD reagents, calibrators, control materials and other components by the manufacturer, based on experimentally determined stability properties (ISO 18113-1); NOTE 2: Guidelines for determining the stability of IVD medical devices are found in EN 13640 (ISO 18113-1); NOTE 3: Adapted from EN 375:2001, definition 3.6 (ISO 18113-1). NOTE 4: Also referred to as “expiration date.”
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expiry date See expiration date
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exploratory biomarker type of biomarker with the most weakly established clinical validity. Exploratory biomarkers are insufficient for regulatory decision making NOTE: They are typically used in the early stages of clinical development when hypotheses are being developed and tested, in situations of enduring uncertainty about disease targets, in situations of unrestrained inconsistency in drug response, in the selection of new compounds, or to bridge the results of animal model studies to clinical expectations.
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exposure a dose of drug administered to the body as measured in plasma or other biological fluids Project: M23 NOTE: Various measures of acute or integrated drug concentrations can be used, such as maximum and minimum concentration (Cmax, Cmin) and area under the curve.
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exposure control plan (ECP) a written plan required by OSHA that identifies those tasks and procedures in which occupational exposure may occur and that identifies the positions whose duties include those tasks and procedures identified as having occupational exposure Project: X03 NOTE: The ECP requires the employer to identify the individuals who will receive the training, protective equipment, vaccination, and other protections of the standard. The plan must be reviewed and updated at least annually.
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exposure incident a specific eye, mouth, other mucous membrane, nonintact skin, or parenteral contact with blood or other potentially infectious materials that results from the performance of an employee's duties Project: X03
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expression the conversion of the genetic instructions present in a DNA sequence into a unit of biological function in a living cell Project: MM13, MM19, MM22, MM24 NOTE: Expression typically involves the process of transcription of a DNA sequence into an RNA sequence followed by translation of the RNA into protein; the RNA may be spliced before translation to remove introns and form mature RNA.
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expression (antigen) in H62, the intracellular or cell surface presence of a protein molecule
Project: H62
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expression profiling the measurement of the activity (ie, expression) of thousands of genes at once to create a global picture of cellular function, often using DNA microarrays Project: MM22
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extended measuring interval the interval within which measurand concentration values are measured with acceptable accuracy by diluting a specimen before taking a measurement within the analytical measuring interval Project: EP34
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extensible markup language (XML) a meta-language widely used on the Web and for business-to-business data exchange Project: POCT01 NOTE: XML is to data and information as HTML is to documents and presentations.
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extensible markup language (XML) a language widely used for data exchange in electronic communications Alternate Term: XML Project: POCT02 NOTE: XML is to data and information as HyperText Markup Language (HTML) is to documents and presentations (HTML is another widely utilized Internet language format).
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extension the 5′ to 3′ synthesis of DNA, starting from an annealed primer to generate a complementary strand of DNA Project: MM09
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extensively drug-resistant tuberculosis Mycobacterium tuberculosis strains that are resistant to rifampin, isoniazid, at least one fluoroquinolone, and at least one of three injectable antimycobacterial agents (ie, kanamycin, amikacin, and capreomycin) Project: M48
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external assessment systematic process conducted by an organization external to the laboratory to collect and analyze data to determine compliance with specified requirements Project: QMS17, QMS01 Source: Quality Glossary NOTE 1: External assessment can also be referred to as an audit, inspection, site visit, or survey; NOTE 2: For the purposes of QMS17, proficiency testing is excluded; NOTE 3: The terms “mock inspection” or “self-assessment” can be used when a laboratory assesses itself for compliance using an external assessment organization’s requirements. In this case, the laboratory is doing an “internal” assessment of itself.
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external assessment organization for purposes of QMS17, refers to all authorities providing audits, site visits, inspections, or surveys Project: QMS17 NOTE: An external assessment organization can also be referred to as the assessment organization.
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external asset (or external specimen) an asset or specimen that was previously accessioned into at least one referring (external, outside) laboratory’s information system before receiving it into the performing laboratory for testing Project: AUTO14 NOTE 1: An external specimen or asset will have one external accession or case identification for each referring laboratory that has accessioned it; NOTE 2: The universal location identifier of the referring laboratory is always different from the universal location identified of the performing laboratory, but the accession or case identification generated by the referring laboratory can overlap with a current or future accession or case identification generated by the performing laboratory that belongs to a different specimen and patient.
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external control in FISH, usually a reference slide that is hybridized in parallel with the test slide Project: MM07 NOTE: An external normal male control slide is usually required to confirm that hybridization was successful for tests involving targets on the Y chromosome.
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external control cells of known phenotypic expression, present in a separate sample distinct for a patient or unknown sample, analyzed to define levels of antigenic expression and serve as an indicator of assay specifications being fulfilled Project: H52, H62 NOTE: Positive and/or negative expression and fluorescent intensity of such cells serve as process controls. External controls are generally used when internal controls are impractical or not available, because external controls are inferior by not ensuring that the patient sample was tested in the exact sample manner.
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external control control material that mimics patient specimens and monitors the testing process from specimen application to result interpretation Project: MM19, MM22, MM24
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external failure cost cost occurring after delivery or shipment of a product or during or after provision of service to the customer Project: QMS20
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external laboratory see referring laboratory Project: AUTO14
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external quality assessment a program in which multiple samples are periodically sent to members of a group of laboratories for analysis and/or identification, in which each laboratory’s results are compared with those of other laboratories in the group and/or with an assigned value Alternate Term: proficiency testing Project: EP31
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external quality assessment evaluation of the laboratory’s performance on examination of samples of external origin for the purposes of determining adequacy of the laboratory’s preexamination, examination, and postexamination activities (ISO/IEC 17043) Alternate Term: EQA Project: H43, ISO Guide 43-1, GP26, H42, H26, MM14 NOTE 1: Used to establish between-laboratory and between-instrument comparability that is, if possible, in agreement with a reference standard (where one exists). External quality assessment schemes may be regional, national, or international. They may also be limited to the users of a particular instrument. It is sometimes also referred to as “proficiency testing,” especially when the external agency is a regulatory agency; NOTE 2: Interlaboratory comparisons and other performance evaluations that may extend throughout all phases of the testing cycle, including interpretation of results; determination of individual and collective laboratory performance characteristics of examination procedures by means of interlaboratory comparison; NOTE 3: The primary objectives of external quality assessment are educational and may be supported by additional elements.
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external quality assessment evaluation of the pulmonary laboratory’s performance on a specific quality method (mechanical or biologic) for the purposes of determining adequacy of the laboratory’s pretesting, testing, and posttesting activities (modified from ISO Guide 43) Project: QMS07
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external quality assessment interlaboratory comparisons and other performance evaluations that may extend throughout all phases of the testing cycle, including interpretation of results; determination of individual and collective laboratory performance characteristics of examination procedures by means of interlaboratory comparison Project: QMS24
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external quality assessment evaluation of the laboratory’s performance on examination of samples of external origin for the purposes of determining adequacy of the laboratory’s preexamination, examination, and postexamination activities (ISO/IEC 17043) Project: H52 NOTE: Used to establish between-laboratory and between-instrument comparability that is, if possible, in agreement with a reference standard (where one exists). External quality assessment schemes may be regional, national, or international. They may also be limited to the users of a particular instrument. It is sometimes also referred to as “proficiency testing,” especially when the external agency is a regulatory agency.
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external quality control for CLSI document C50, external quality control and assurance or proficiency testing is the evaluation of analytical performance that includes a sample for which the analyst does not know the expected measurement result Alternate Term: external quality assurance; EQA; proficiency testing; PT Project: C50 NOTE 1: A “blank” quality control sample is not acceptable as an external (“blind”) quality control material, although it is appropriate as an internal (“bench”) quality control material; NOTE 2: Standards are acceptable external (“blind”) quality control specimens provided the analyst does not know the expected result for the standard.
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external RNA control the RNA species that are added to an RNA sample prior to enzymatic manipulations with the purpose of qualitatively assessing technical performance of the amplification or hybridization or the performance of the assay platform Project: MM16
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extracorporeal life support cardiopulmonary bypass that circulates the blood outside of the body Alternate Term: extracorporeal membrane oxygenation Project: NBS03 NOTE: This procedure requires exposure to red blood cells and should be considered a transfusion of blood products for the purposes of newborn screening.
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extracted ion chromatogram chromatogram created by plotting the intensity of the signal observed at a chosen m/z value or series of values in a series of mass spectra recorded as a function of retention time (IUPAC 2006) Project: C43
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extracted ion chromatogram a postacquisition process by which the ion current of one (or several) m/z values acquired in a spectral scan mode are selected and displayed as a function of time Project: C50 NOTE: This function simulates selected ion monitoring, but offers no enhancement of sensitivity.
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extracted ion chromatogram a plot of signal intensity of one or more m/z values as a function of time from a series of continually collected mass spectra Project: C64
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extraction See nucleic acid extraction
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extraction blank a blank that incorporates only the extraction agents in subsequent testing
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extraction hood cabinet or cover above a laboratory device for the extraction of air or fumes directly to the exterior of a building, which prevents their general circulation (modified from ISO 15190) Alternate Term: fume hood
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extraction hood cabinet or cover above a laboratory device for the extraction of air or fumes which prevents their general circulation (ISO 15190) Alternate Term: fume hood Project: ISO 15190
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extralabel use the use of an approved human or animal drug in animals in a manner that is not in accordance with the approved labeling Project: VET01, VET06, VET09
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extrapolate to estimate (the value of a variable) outside the tabulated or observed range Project: H54 NOTE: International normalized ratios above 4.5 would be extrapolated, while those between 1 and 4.5 would be interpolated.
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extremely low birth weight birth weight < 1000 g Project: NBS03
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extrinsic blood coagulation pathway the activation of Factor X by Tissue Factor/VIIa complex
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extrinsic coagulation pathway the activation of the clotting cascade, which starts with the interaction of factor VII and tissue factor Project: POCT14
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extrinsic factor pathway mechanism of the coagulation pathway in vivo is tissue factor binding to activated Factor VII which activates Factor X and Factor IX Project: H48 NOTE 1: Activated Factor X converts prothrombin to thrombin, with activated Factor V, merges with extrinsic pathway into common pathway; NOTE 2: This pathway is measured by the prothrombin time; NOTE 3: Activation of Factor IX by VIIa/tissue factor complex occurs in vivo only. Factor IX is not assessed in the prothrombin time.
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exudate as a subtype of pleural fluid, due to inflammation and characterized by high protein and presence of cells
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exudate the accumulation of a fluid having a high concentration of protein in a body cavity caused by increased capillary permeability usually secondary to inflammation Project: M54
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exudate a fluid with a high concentration of protein or cells that accumulates in a body cavity as a result of increased capillary permeability Project: H56
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eyewash station unit designed to allow people to flush their eyes and face with water in case of a chemical or biological spill Project: QMS04
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f prefix indicating that the pharmacokinetic parameter values or pharmacokinetic/pharmacodynamic index values are based on unbound (free) fractions of the drug Project: M23
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F cell a non-nucleated erythrocyte or red cell containing hemoglobin F in addition to other hemoglobin types NOTE: It is found in all individuals of all ages, as distinct from fetal red cells, which contain hemoglobin F as the sole or predominant hemoglobin type and are only found in the in utero fetus, newborn, and pregnant female circulation or fluids containing blood.
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face velocity the speed of the air moving into a cabinet or hood measured at the front opening Project: QMS04
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facilitator individual responsible for keeping participant discussions on track with the exercise design objectives and making sure all issues and objectives are explored as thoroughly as possible within time constraints during a discussion-based exercise Alternate Term: controller Project: GP36
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factor inhibitor antibodies that neutralize the activity of a specific clotting factor Project: H48 NOTE: Some inhibitors are so strong that they may affect other factors.
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factor sensitivity (of a reagent) responsiveness of the reagent to one or more specific factor deficiencies Project: H48 NOTE: Variation in responsiveness is likely due to differences in the activator and/or phospholipids used in the reagent.
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Factor VIII a plasma glycoprotein which, when activated by thrombin, functions as a cofactor in the conversion of Factor X to Factor Xa Project: H51 NOTE: It is normally carried and stabilized by von Willebrand factor; its reduction in plasma is the cause of hemophilia A.
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factorial experiment experimental design in which all possible treatment combinations formed from two or more factors, each being studied at two or more levels, are examined so that interactions (differential effects) as well as main effects can be estimated
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facultative anaerobe a microorganism that can multiply in the presence or absence of oxygen Project: M56
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failure in the broadest sense, a case when the system does not meet customer expectations Project: EP18, POCT07, QMS20, GP47 NOTE 1: Failure includes the laboratory’s inability to perform its intended functions satisfactorily or within specified performance limits; NOTE 2: Errors of measurement and errors of use are subsets of failures.
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failure in the broadest sense, a case when the system does not meet the user’s expectation Project: EP23 NOTE 1: This includes the inability to perform its intended functions satisfactorily or within specified performance limits; NOTE 2: Errors of measurement and errors of use are subsets of failures.
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failure cause physical or chemical processes, design defects, quality defects, part misapplication, or other processes which are the basic reason for failure or which initiate the physical process by which deterioration proceeds to failure (MIL-STD-1629A. Procedures for Performing a Failure Mode, Effects and Criticality Analysis. 24 November 1980.)
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failure effect consequence(s) a failure mode has on the operation, function, or status of an item. Failure effects are classified as local effect, next higher level, and end effect (MIL-STD-1629A. Procedures for Performing a Failure Mode, Effects and Criticality Analysis. 24 November 1980.)
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failure mode manner by which a failure occurs Project: EP18, POCT07, EP23, GP47
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failure mode and effects analysis analysis technique for system reliability, based on assumptions of possible failure states of each component of a device or system (IEC 60812) Alternate Term: FMEA Project: POCT02
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failure modes and effects analysis 1) systematic review of an instrument system or process that examines how failures can affect the instrument system or process, the test results, or the testing personnel; 2) systematic review of a system or process that examines how failures can affect performance Project: EP18, POCT07, GP33 NOTE 1: Failure modes and effects analysis involves identification of potential failure modes, determining the consequences of each failure, and reviewing the control measures implemented to prevent or detect the failure; NOTE 2: If estimating the risk of the failures and the risk of harm is part of the analysis, the technique is called “failure mode, effects, and criticality analysis”; NOTE 3: Failure modes and effects analysis is considered a “bottom-up” analysis; NOTE 4: See CLSI document EP18 for further information.
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failure modes and effects analysis systematic review of a system or process that examines how failures can affect performance NOTE 1: Failure modes and effects analysis involves identification of potential failure modes, determining the consequences of each failure, and reviewing the control measures implemented to prevent or detect the failure; NOTE 2: If estimating the risk of the failures and the risk of harm is part of the analysis, the technique is called “failure modes, effects, and criticality analysis.”
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Failure Reporting and Corrective Action System a process by which failures are identified and analyzed so that corrective actions can be implemented Project: EP18
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failure reporting, analysis, and corrective action system a process whereby a system is tested, and failures are observed and classified by severity and frequency of occurrence Project: POCT07 NOTE 1: The failures are ranked by criticality, the product of severity, and frequency of occurrence; NOTE 2: The most important problems are corrected; NOTE 3: See CLSI document EP18 for further information.
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false negative See false-negative result Alternate Term: false-negative result Project: I/LA28
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false negative an observation for which no event alarm occurs, although there is a relevant symptomatic event Project: MM19
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false negative a negative test result for a disease or condition when the disease or condition is present Project: M53, MM22, MM24
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false positive a positive test result for a disease or condition when the disease or condition is not present Project: M47, M53, MM19, MM22, MM24 NOTE: For blood cultures, 1) a culture that yields a microbial isolate(s) that is determined not to be the cause of bloodstream infection, or 2) a culture with objective evidence of microbial growth (ie, an instrument signal that indicates microbial growth) but for which subcultures and stains are negative.
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false positive See false-positive result Alternate Term: false-positive result Project: I/LA28
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false-negative (clinical) newborn dried blood spot screening result a screen-negative result reported in an affected newborn Project: NBS07 NOTE: As used in NBS07, a screen-negative result of a newborn dried blood spot screening algorithm (based on the detected acid α-glucosidase enzyme activity above the cutoff) reported for a newborn later diagnosed with Pompe disease.
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false-negative fraction ratio of subjects who have the disease, but who have a negative test result, to all subjects who have the disease; FN / (FN + true positive [TP]); equivalent to (1 − sensitivity) Project: EP24
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false-negative rate rate of negative test results for a disease or condition when the disease or condition is present Project: POCT07
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false-negative rate the rate needed for calculating negative predictive value incorporating prevalence
Project: MM12 [1 - P (T + | D + ) ] P (D +) ÷ 1 - P(T +)
Where: T = test result, D = disease/state of interest, and P(D+) = prevalence of disease or state of interest (ie, probability that the disease or state of interest is present in the target population).
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false-negative ratio the ratio of subjects who have the disease, but who have a negative test result, to all subjects who have the disease (false negatives + true positives); false-negative ratio = false negatives/(false negatives + true positives) Project: GP10, MM12
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false-negative result a negative test result for a patient or specimen who is positive for the condition or constituent in question Alternate Term: false negative Project: POL1/2, I/LA23, MM01, H20
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false-negative result a negative test result for a subject in whom the condition of interest is present (as determined by the diagnostic accuracy criteria) Project: EP33 NOTE: In the context of EP33, a false-negative result indicates that a delta check alert did not occur when there was a sample issue or patient condition change that should have been identified.
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false-negative result a negative test result for a disease or condition when the disease or condition is present Project: MM21
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false-negative result a negative test result for a patient or specimen that is positive for the condition or constituent being investigated Alternate Term: false negative Project: MM09, MM12, MM17
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false-negative result a negative test result for a patient or specimen that is known or subsequently proved to be positive for the condition or constituent in question Alternate Term: false negative Project: I/LA28
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false-negative result negative test result for a subject in whom the disease or condition of interest is present Project: EP24, H60 NOTE 1: Alternatively, a person who has a condition but is incorrectly identified as negative for having the condition; NOTE 2: The term is often unclear in lupus anticoagulant testing because a gold standard test is lacking.
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false-negative screening result screen-negative result in an affected newborn Project: NBS01, NBS09, NBS05, NBS03 Source: Newborn Screening Glossary NOTE 1: A screen-negative result indicating that an individual is not at increased risk for the primary target disease when the individual is found later to be affected; NOTE 2: For quantitative tests such as immunoreactive trypsinogen, this refers to an “in-range” result in an affected child; NOTE 3: For qualitative tests such as DNA analysis, this may include failure to detect cystic fibrosis transmembrane conductance regulator gene variants; NOTE 4: As used in NBS09, a screen-negative result of a laboratory screening algorithm (based on the detected C26:0-lysophosphatidylcholine concentration below the cutoff) reported for a newborn later diagnosed with adrenoleukodystrophy; NOTE 5: See primary target disease.
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false-positive (clinical) newborn dried blood spot screening result a screen-positive result reported in an unaffected newborn Project: NBS07 NOTE: As used in NBS07, the positive result of a newborn dried blood spot algorithm (based on the deficiency of acid α-glucosidase activity) that is obtained for a newborn who does not have Pompe disease (including carriers for a acid α-glucosidase gene mutation).
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false-positive fraction ratio of subjects who do not have the disease, but who have a positive test result, to all subjects who do not have the disease; FP / (FP + true negative [TN]); same as (1 − specificity) Project: EP24
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false-positive rate the rate needed for calculating positive predictive value incorporating prevalence
Project: MM12 P (T+ | D- ) [1 - P (D+)] ÷ P(T +)
Where: T = test result, D = disease/state of interest, and P(D+) = prevalence of disease or state of interest (ie, probability that the disease or state of interest is present in the target population).
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false-positive rate rate of positive test results for a disease or condition when the disease or condition is not present Project: POCT07
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false-positive rate proportion of unaffected individuals with positive test results Project: I/LA25
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false-positive ratio the ratio of subjects who do not have the disease, but who have a positive test result, to all subjects who do not have the disease (false positives + true negatives); false positives/(false positives + true negatives) Project: GP10, MM12
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false-positive result a positive test result for a patient or specimen that is negative for the condition or constituent in question Alternate Term: false positive Project: NRSCL8, I/LA23, MM12, H20 | | | Test Method Results | | Reference Method Results | Positive | Negative | | Positive | TP (True Positive) | FN (False Negative) | | Negative | FP (False Positive) | TN (True Negative) |
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false-positive result a positive test result for a disease or condition when the disease or condition is not present Project: MM21
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false-positive result a positive test result for a patient or specimen that is negative for the condition or constituent being investigated Alternate Term: false positive Project: MM12, MM17, MM09
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false-positive result a positive test result for a subject in whom the condition of interest is absent (as determined by the diagnostic accuracy criteria) Project: EP33 NOTE: In the context of EP33, a false-positive result refers to a delta check alert that does not identify the type of change of interest to the laboratory.
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false-positive result a positive test result for a patient or specimen who is negative for the condition or constituent in question Alternate Term: false positive Project: MM01
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false-positive result positive test result for a subject in whom the disease or condition of interest is absent Project: EP24, H60 NOTE 1: Alternatively, a person who does not have the condition but is incorrectly identified as positive for having the condition; NOTE 2: The term is often unclear in lupus anticoagulant testing because a gold standard test is lacking.
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false-positive result a positive test result for a patient or specimen that is known or subsequently proved to be negative for the condition or constituent in question Alternate Term: false positive Project: I/LA28
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false-positive screening result screen-positive result in an unaffected newborn Project: NBS09, NBS01, NBS05, NBS03 Source: Newborn Screening Glossary NOTE 1: A screen-positive result indicating that an individual is at increased risk for a target disease when the individual is found later to be unaffected; NOTE 2: For quantitative tests such as immunoreactive trypsinogen, this refers to “out-of-range” results in an unaffected child; NOTE 3: For qualitative tests such as DNA analysis, this may include detection of cystic fibrosis transmembrane conductance regulator (CFTR) variants in a carrier or detection of CFTR variants that are not actually present; NOTE 4: As used in NBS09, a screen-positive result of a laboratory screening algorithm (based on the detected C26:0-lysophosphatidylcholine concentration above the cutoff) reported for a newborn who does not have adrenoleukodystrophy; NOTE 5: See primary target disease.
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family history the genetic relationships and medical history of a family Project: MM19 NOTE: When represented in diagram form using standardized symbols and terminology, it is usually referred to as a pedigree.
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Faraday cage an enclosure surrounding an electrochemical measurement system that serves as a shield against interference from ambient electromagnetic signals Project: C39
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fastidious requiring specialized conditions for growth Project: M54, M56
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fasting glucose the concentration of glucose in whole blood or plasma after refraining from consumption of food or sugar-containing beverages for at least eight hours Project: POCT13 NOTE: In contrast, see nonfasting glucose.
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fatality usual term for deceased person resulting from an accident or disaster, to be distinguished in emergency parlance from “casualty” Project: GP36
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fault state of an item, characterized by the inability to perform a required function, excluding inabilities due to preventive maintenance, other planned actions, or lack of external resources Project: EP23
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fault tree analysis systematic review of an instrument or system to identify potential sources of failure that starts by assuming a main system failure and determines what could cause it Project: EP18, POCT07 NOTE 1: Fault tree analysis is considered a “top-down” analysis; NOTE 2: Fault tree analysis is more efficient than failure modes and effects analysis for analyzing combinations of failure events and human-use failures; NOTE 3: Fault tree analysis and failure modes and effects analysis are often used together to evaluate complex systems for a comprehensive top-down and bottom-up risk analysis; NOTE 4: See CLSI document EP18 for further information.
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fault tree analysis (FTA) systematic review of a system or product to identify sources of potential failure; particularly useful in safety and reliability analyses Project: ISO 15198 NOTE First, a list of potential failure modes is developed. For each, an analysis is conducted to (1) determine the primary causes; (2) the secondary causes behind the primary causes; and (3) possibilities to mitigate the primary and the secondary causes.
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fault tree gates BASIC – the lowest level event in a tree branch; AND – the output occurs if and only if all the input (lower in tree) events occur; OR – the output occurs if and only if at least one of the input (lower in tree) events occur; PAND – the output occurs if and only if all input (lower in tree) events occur in a particular order Project: EP18
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Fc the portion and/or fraction of the IgG molecule derived from papain digestion that consists of the C-terminal half of the H chain. Certain biological properties are associated with this fragment, which sometimes can be easily induced to form crystals Project: DI01
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Fc receptor a protein found on the surface of certain cells—including natural killer cells, macrophages, neutrophils, lymphocytes, and mast cells—that contribute to the protective functions of the immune system Project: ILA29 NOTE: The name is derived from the receptor’s binding specificity for a part of an antibody known as the Fc (fragment, crystallizable) region. Fc receptors bind to antibodies that are attached to infected cells or invading pathogens. Their activity stimulates phagocytic or cytotoxic cells to destroy microbes, or infected cells by antibody-mediated phagocytosis or antibody-dependent cell-mediated cytotoxicity.
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F-distribution {a parametric} probability distribution of a continuous random variable, which can take any value from 0 to + ¥ (ISO 3534-1-1.41) Project: ISO 3534-1- NOTE: This is the distribution of the quotient of two independent X 2 {chi-squared} distributed random variables, each one divided by its number of degrees of freedom (ISO 3534-1-1.41).
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feasibility a part of the Feasibility and Design Phase in the Establishment Stage of the Test Life Phases Model. This phase includes consideration of a potential test method, by the developer, concerning various issues that are relevant to the advisability of developing a new test method Project: EP19 NOTE: Issues could include the potential market for the test method, client expectations, and strategic plans for the institution.
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feature a defined segment of single-stranded nucleic acid immobilized on a solid substrate (ie, microarray) that is used to identify specific DNA or RNA molecules having a complementary sequence Project: MM12
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feature a single miniaturized hybridization reaction area on the solid surface of the microarray where multiple copies of the single nucleic acid probe are immobilized Project: MM22, MM24
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feed water the water that is introduced into a purification process Project: GP40
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Felgett advantage for weak signals, if multiple mass spectra are averaged, the signal-to-noise ratio for a peak corresponding to an analyte signal will improve when compared to random chemical or electronic noise present in the spectrum Project: C50 NOTE: The increase in signal-to-noise ratio observed is proportional to the square root of the number of scans averaged.
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fetal lung immaturity the absence of lung maturity in a fetus, primarily due to an insufficient quantity of pulmonary surfactant that is nearly always associated with preterm birth Project: C58
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fetal lung maturity the presence of a functional fetal lung as indicated by an adequate amount of pulmonary surfactant Project: C58
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fetal red blood cell a nucleated normoblast (red blood cell precursor) or non-nucleated erythrocyte containing hemoglobin F as the predominant hemoglobin type and produced by an in utero fetus NOTE: It may be found in maternal circulation, as red cells, which contain hemoglobin F as the predominant hemoglobin type, but distinct from those F cells present in adult circulation in the nonpregnant individual.
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fibrinogen a plasma glycoprotein that is converted to fibrin by thrombin and supports platelet aggregation Project: H51
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fibrinogen assay the assay of fibrinogen concentration commonly measured by the rate at which it is converted to fibrin by the action of thrombin Project: H30 NOTE 1: It is described in CLSI/NCCLS document H30; NOTE 2: Other methodologies include precipitation/gravimetric, immunological, and nephelometric procedures.
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fiducial refers to the use of geographic markings on a microarray that permit the orientation of that device as to left, right, up, and down Project: MM12 NOTE 1: Fiducial markings are typically fluorochrome labeled oligonucleotides comprised of irrelevant sequence; such markers do not hybridize to the target sequence, and are therefore detected as fluorescent spots on the microarray independent of the controls or of the test samples; NOTE 2: Fiducial markings are typically fluorochrome labeled oligonucleotides comprised of irrelevant sequence; such markers do not hybridize to the target sequence, and are therefore detected as fluorescent spots on the microarray independent of the controls or of the test samples.
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fiducial error (of a measuring instrument) error of a measuring instrument divided by a value specified for the instrument (VIM93) NOTE: The specified value is generally called the fiducial value, and may be, for example, the span or the upper limit of the nominal range of the measuring instrument.
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field one specific attribute of a record which may contain aggregates of data elements further refining the basic attribute Project: LIS02
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field correction correction applicable to a device already released by the manufacturer Project: HS11 NOTE: A correction may be performed without removing the device to another location or returning it to the manufacturer.
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filariform larvae slender, infective larvae of Strongyloides stercoralis and hookworm Project: M28
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filler a person or service that produces the observations requested by the placer Project: AUTO01, AUTO02, AUTO03
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filtration a purification process in which the passage of fluid through a porous material results in the removal of impurities based on the physical interaction of the impurities with that porous material Project: GP40
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finding conclusion drawn by evaluating the collected audit evidence against the audit criteria (modified from ISO 9000, ISO 19011) Project: QMS15
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fine needle aspiration the process of obtaining a sample of cells and bits of tissue for examination by applying suction through a fine needle attached to a syringe Project: MM17
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fire egress route used to get out of a building in case of a fire Project: QMS04
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fire rating rating of a wall or door used to protect an area from a fire for a certain amount of time Project: QMS04 NOTE: Normally listed in hours of 1, 2, 3, or as smoke containment.
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firewall a security component/device protecting a network (as a configuration with high confidentiality level) against areas of low confidentiality level (eg, the Internet); it can also be used within a network to protect a specific sensitive part of a network (eg, a laboratory information system) Project: POCT02 NOTE 1: The primary function of a firewall is to let “good” traffic pass through while “bad” traffic gets blocked by analyzing and filtering the “good” data packages; NOTE 2: Firewalls intercept attacks before the operating system can even acknowledge them; NOTE 3: A software firewall (often called “personal firewall”) is used to protect a specific computer against the outside. This software is nestled between the network drivers and the operating system, relieving the operating system from the filtering task and protecting it from getting infected.
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firewall an internetwork gateway that restricts data communication traffic to and from one of the connected networks (the one said to be “inside” the firewall) and thus protects that network’s system resources against threats from the other network (the one that is said to be “outside” the firewall) (RFC 2828) Project: AUTO09
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firmware computer programs contained permanently in a hardware device (as read-only memory) Project: I/LA33
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first isolate refers to the initial microbial isolate of a given species (with antimicrobial susceptibility testing results reported) recovered from a single patient during the time period analyzed (eg, one year) for the antibiogram regardless of specimen source, specimen type, antimicrobial susceptibility profile, or other phenotypical characteristics (eg, biotype) Project: M39 NOTE: If analysis of a subset of isolates is being performed (eg, isolates from blood cultures or methicillin [oxacillin]-resistant Staphylococcus aureus isolates), “first isolate” would refer to the first isolate in that particular subset (ie, the patient’s first blood isolate or methicillin [oxacillin]-resistant Staphylococcus aureus isolate, respectively).
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first morning specimen (overnight, early-morning, eight-hour) a urine specimen collected immediately upon awakening in the morning Project: GP08 NOTE: This is also known as an overnight, early-morning, or 8-hour specimen.
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first-order degradation a product degradation reaction rate that can be described by a linear differential equation, leading to an exponential relationship between the product concentration and the reaction time Project: EP25
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first-order kinetics degradation a product degradation reaction rate that can be described by a linear differential equation, leading to an exponential relationship between the product concentration and the reaction time
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first-tier screen (for newborn screening) a single assay, combination of assays, physiological measurement, or assessment performed on all newborns to screen for a disease, group of diseases, or phenotypic difference as the first step in the laboratory screening algorithm Alternate Term: first-tier screening; first-tier testing Project: NBS03, NBS08, NBS13, NBS09, NBS10 Source: Newborn Screening Glossary NOTE 1: Also called “primary screening test”; NOTE 2: See laboratory screening algorithm, screening test, second-tier screen, and third-tier screen.
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first-tier testing primary testing that in some instances may require additional testing before reporting the primary test result, or subsequent to reporting the primary test result, as the standard of care dictates Project: GP49 NOTE: The second-tier test is also referred to as a “reflex test.”
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fishbone diagram diagram that shows the causes of a certain event Project: EP23 NOTE: Common uses of the diagram are product design and quality defect prevention to identify potential factors causing an overall effect.
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FITC the form of fluorescein most commonly conjugated to ligand molecules Alternate Term: Fluorescein isothiocyanate Project: I/LA24 NOTE: This is often used to describe any covalent fluorescein conjugate regardless of the actual conjugation chemistry used.
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fit-for-purpose an approach to analytical validation in which the method is validated as appropriate to the intended use of the data and associated regulatory requirement Project: H62
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fitness for purpose a term used to indicate that a method or service fits the analyst’s defined purpose for that measurand Project: EP32
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fixation the process by which biological and autolytic processes of a biological specimen are halted by chemical means Project: I/LA28 NOTE: The goal of fixation is to result in a piece of tissue or cellular preparation that is stable for storage and analysis later.
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fixed casework system premanufactured casework system that is fixed (bolted) to the floor, wall, and/or each other Project: QMS04
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fixed cost a periodic cost that remains more or less unchanged irrespective of output level or sales revenue (BusinessDictionary.com)
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flagging an instrument function identifying a sample or blood film for further attention or review Project: H20
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flame mode in the flame mode, a factor can be applied to results generated by direct ion-selective electrode systems that makes the results comparable to those generated by indirect systems for patient specimens normal in protein and lipid content Project: C29
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flammable liquid a liquid with a flash point less than 38°C (100°F) Project: QMS04
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flash point the lowest temperature that the vapor above a liquid will ignite when an ignition source is introduced Project: QMS04
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flection the point at which the vertical (straight) walls of the specimen container bend to form the base Project: AUTO01, AUTO02
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flexibility the ease with which a system or component can be modified for use in applications or environments other than those for which it was specifically designed Project: AUTO08
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flexible casework system premanufactured casework system that is easily changeable in aspects, including countertop height and storage components Project: QMS04
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flood shower a shower located in laboratories that is used for emergency purposes, eg, in case of accidental chemical spills, biological spills, or fire Alternate Term: emergency shower Project: QMS04 NOTE: Also called an emergency shower.
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floor plans graphic drawings created to show the layout of a space from the perspective of looking down upon it Project: QMS04
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flow chart diagram, often using geometric symbols, showing the sequence of activities and decisions made in a process Alternate Term: process map Project: QMS18, QMS02, QMS01 Source: Quality Glossary
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flow crossmatch a test for compatibility between recipient and donor by testing recipient cells with donor cells Alternate Term: flow cytometric crossmatch Project: ILA29 NOTE: If the recipient has antibody against antigens present on the donor cells, binding will occur. A labeled secondary antibody is added, which will attach to the bound antibody on the cells. Detection of antibody binding is achieved by comparing the level of fluorescence from the secondary antibody between the test serum and the negative control.
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flow cytometer a microphotometer in which the sample consists of a stream of cells or other particles, ideally flowing in single file through a sensing region from which optical signals are collected as each particle is illuminated one at a time Project: I/LA24
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flow cytometry the analysis of cells or microparticles on an instrument in which one cell or particle at a time passes through the aperture and is analyzed by detecting fluorescent staining Project: ILA29
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flow cytometry a methodologically oriented subdiscipline of analytical cytology that measures cells in suspension in a liquid vehicle as they pass, typically one cell at a time, by a measurement station Project: H44 NOTE: The measurement represents transformations of changes in the output of a detector (or detectors) due to changes in scattered light, absorbed light, light emitted (fluorescence) by the cell, or changes in electrical impedance, as the cell passes through the measuring station.
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flow cytometry standard data file standard for the output files generated by cytometry instruments Project: H62
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fluorescein isothiocyanate a chemical that is commonly used to label proteins and, when excited at an appropriate wavelength (typically a “blue” 488 nm argon laser) of ultraviolet light, will emit a fluorescent signal detectable by appropriate instrumentation Project: I/LA26 NOTE: Fluorescein isothiocyanate is excited maximally at approximately 490 nm with an emission maximum at 520 nm.
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fluorescein isothiocyanate the most common fluorochrome used for cell immunophenotyping Alternate Term: FITC Project: H42, H43, H52 NOTE: Fluorescein conjugates absorb maximally at approximately 490 nm, close to the 488-nm emission of argon lasers, and emit maximally near 525 nm. Each conjugated fluorescein molecule adds a net negative charge to the antibody, and therefore may change its potential binding characteristics.
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fluorescence brief electromagnetic radiation emitted as a result of absorption of radiation (photons) by an atom, molecule, or ion Project: NRSCL8, I/LA24 NOTE: Generally, fluorescent radiation has a longer wavelength than the absorbed radiation.
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fluorescence brief visible electromagnetic radiation signal emitted because of absorption of radiation (photons) by an atom, molecule, or ion Project: I/LA28
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fluorescence compensation a mathematical or electronic correction applied to flow cytometric data to account for the overlapping fluorescence emission from one fluorophore into the wavelength region where a second is to be measured when both are present on the same cell; the desired result is that each corrected signal should reflect the emission of a single fluorophore Project: H62 NOTE 1: Compensation is achieved by subtracting a fraction of one measured fluorescent signal from each of the other fluorescent signals; NOTE 2: The correction needed is determined by measuring the signal from appropriate single-stained controls in each detector; NOTE 3: The number of signals involved is equal to the number of fluorophores (N) used, and the number of compensation coefficients to be determined is represented by an N × N dimensional matrix. Values for the correlation coefficients are determined by inverting the spillover matrix generated by analyzing single-color controls; NOTE 4: See spillover matrix, compensation matrix, and spectral overlap.
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fluorescence energy transfer immunoassay a type of sandwich fluorescence immunoassay of an antigen with multivalent antigenic determinants in which antibodies are labeled with donor and acceptor fluorescence markers Project: H59 NOTE 1: The reaction of at least two antibodies with the targeted antigen, resulting in the approximation of these two determinants closer than a critical distance of 50 to 70 Angstroms that quenches the fluorescence; NOTE 2: The reduction in fluorescence emission is proportional to the antigen concentration.
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fluorescence enhancement the increased fluorescent emission due to a change in the environment of the excited molecules Project: NRSCL08
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fluorescence excitation transfer nonradiative energy exchange between a fluorescer (donor) and a quencher (acceptor) Project: NRSCL08 NOTE: Caused by a dipole-dipole resonance energy transfer mechanism that exists when there is overlapping of the fluorescer emission spectrum and the acceptor absorption spectrum.
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fluorescence immunoassay (FIA) a generic term for an immunoassay in which the analyte content of the sample is measured by the amount of fluorescence from bound antibody or antigen NOTE: Immunoassays that use a fluorogenic enzyme substrate (eg, methylumbelliferone phosphate) can also be classified as fluorescence immunoassays.
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fluorescence immunoassay a type of immunoassay in which the antigen or, as in the case of D-dimer, antibody is labeled with a fluorescent compound that emits light at a wavelength when excited by a light at a different wavelength or by a chemical reaction Project: H59
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fluorescence in situ hybridization (FISH) a technique in which genes are localized in chromosome preparations of cell nuclei using fluorescently labeled probes Project: MM05 NOTE: In the context of molecular diagnosis of hematological malignancies, FISH is used to detect chromosomal rearrangements of specific genes.
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fluorescence intensity a measurement of the active, or apparent, amount of fluorophore bound to a particle or cell
Project: H42, H43, H52, H62 NOTE 1: Increasing intensity is reflected in a fluorescence signal appearing in a higher channel number. Under appropriate conditions, fluorescence intensity can be related to the number of binding sites a cell has for a particular fluorochrome-conjugated reagent; NOTE 2: Expressed as mean fluorescence intensity (MFI), median fluorescence intensity (MdFI), or geometric mean fluorescence intensity. In situations for which either MFI or MdFI may apply, H62 uses MFI/MdFI. This term does not indicate a mathematical ratio.
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fluorescence intensity 1) the reading on an instrument response scale caused by detection of a portion of the fluorescence emission from excited fluorochromes; 2) a measure of fluorescence radiant power Project: I/LA24
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fluorescence minus one a staining tube that contains all but one of the antibodies/fluorophores in a multicolor panel; it is used to interpret flow cytometry data and to identify and gate cells in the context of data spread in a given panel Project: H62 NOTE 1: For some applications, it is useful to omit more than one antibody/fluorophore; when this is done, the staining tube is often referred to as FMx (fluorescence minus x number of antibodies/fluorophores); NOTE 2: “Full (panel) minus one” recently replaced “fluorescence minus one” in the flow cytometry vernacular. The definition (and “FMO” abbreviation) is the same.
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fluorescence quenching any interaction of the fluorescence molecule with a solvent, solutes, or other environmental factors that lowers the fluorescence quantum yield Project: NRSCL08, I/LA24 NOTE: As used in this document, fluorescence quenching may also be due to decreased absorptivity of the fluorochrome.
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fluorescence resonance energy transfer a type of fluorescent immunoassay, in which a donor molecule (which is usually the substrate) is excited, electronically or by an external light source, and instead of emitting light, the excitation energy transfers to a nearby acceptor molecule (which is the product) Project: H59 NOTE: The excited states of one or both of the donor and acceptor can decay with fluorescence emission. When energy transfer is observed, a reduction in the emission intensity of the donor/substrate with a concomitant increase in the emission intensity from the acceptor/product is observed. The intensity of the longer wavelength emission from acceptor/product is proportional to its amount.
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fluorescence resonance energy transfer the principle of transfer of fluorescent light energy from one dye to another dye, a process which can serve as a label for nucleic acid probes Project: MM03 NOTE 1: Fluorescent energy can be transferred from one dye to another dye located on the same probe (eg, 5′ nuclease assay probes or molecular beacons) or from one dye on one probe to another dye on a second probe that hybridize in a head-to-tail configuration to target nucleic acid (eg, fluorescence resonance energy transfer hybridization probes); NOTE 2: For some probe designs, the transferred energy is absorbed and emitted at a different wavelength. For other probes, the transmitted energy is quenched and no light emission occurs.
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fluorescence spillover overlapping fluorescence emission from one fluorochrome into the wavelength region where a second is to be measured when both are present on the same cell Project: H62 NOTE 1: A fluorophore’s spillover signal intensity in the secondary detector (spillover value) is proportional to its signal intensity in the primary detector; NOTE 2: The number of spillover signals (N) is equal to the number of fluorophores used, and mathematically inverting the N × N spillover matrix generates the compensation coefficients needed for each fluorophore at each detector; NOTE 3: See percent spillover and spillover matrix.
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fluorescence system a fluorescer and other components necessary to produce the measured fluorescence signal that is modulated by the analyte Project: NRSCL08
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fluorescence yield product of the concentration of a fluorochrome in solution or suspension and the quantum yield of the fluorochrome molecule Project: I/LA24
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fluorescer a substance that fluoresces when excited by electromagnetic radiation Alternate Term: fluophor Project: DI01, I/LA23
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fluorochrome reagent that emits visible light when irradiated with excitation light of a shorter wavelength (ISO 19001) Project: ISO 19001, MM22, MM24
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fluorochrome a substance that fluoresces when excited by electromagnetic radiation Project: I/LA24 NOTE: This term is synonymous with, and in I/LA24 supersedes, the terms "fluorescer," "fluorophore," and "fluorophor."
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fluorochrome chemical compound that has the property of absorbing light at one wavelength and emitting light of a longer wavelength Project: H44
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fluorochrome-ligand conjugate as used in this document, a reagent for staining receptor bearing microparticles in which a fluorochrome is covalently attached to a ligand for that particular receptor Project: I/LA24 NOTE: The ligand is most often an antibody raised against the receptor.
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fluorograph graphical representation of the results obtained from real-time polymerase chain reaction amplifications that use fluorescent dyes Project: MM03 NOTE: It plots fluorescence or change in fluorescence as a function of polymerase chain reaction cycle number.
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fluorometer an instrument that measures the intensity of fluorescence Project: DI01
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fluorometer a generic term for any instrument used to measure fluorescence intensity and possibly other qualities of fluorescence emission such as spectral distribution or anisotropy Project: I/LA24 NOTE: This term is synonymous with, and in I/LA24 supersedes, the term "fluorimeter."
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fluorophore fluorescent molecule that absorbs light energy and is promoted to an excited state that is released as fluorescence, in the absence of a quencher, when the fluorophore falls back to the ground state and releases the excess energy Project: MM03, MM22, MM24
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fluorophore a chemical moiety that fluoresces Project: H62 NOTE 1: A chemical that after stimulation with one wavelength of light emits light of a different, usually longer, wavelength; NOTE 2: In flow cytometry, “fluorophore” is often used interchangeably with “fluorochrome” or with the short form, “fluor.”
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FN the number of false-negative results
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follow-up (for newborn screening) actions taken to ensure that a newborn whose specimen is unacceptable or whose screening result warrants additional action receives appropriate repeat screening, diagnostic testing, clinical evaluation, and/or intervention Project: NBS05, NBS02, NBS13, NBS09, NBS03, NBS10 Source: Newborn Screening Glossary NOTE: See intervention.
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follow-up algorithm (for newborn screening) documented process used to ensure that newborn screening results are communicated to the newborn’s specimen submitter and/or health care provider and that additional screening and/or diagnostic testing and clinical evaluation is completed. For affected babies, this process also includes ensuring that treatment is initiated and outcomes are monitored Project: NBS07, NBS06, NBS02, NBS13, NBS10 Source: Newborn Screening Glossary NOTE: See follow-up, short-term follow-up, and long-term follow-up.
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font a specific member of a type family such as roman, boldface, or italic type Project: AUTO12 NOTE: Point size may or may not be an integral component of a font description, depending on whether or not a scalable outline font is being used.
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foot-candle unit of light on a surface one square foot in areas with a uniform distribution of a specific amount Project: QMS04
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force majeure any situation such as an “act of God” (ie, natural disaster), war, strike or labor dispute, embargo, government order, or any other such event for which neither the supplier nor the organization is liable for any failure of or delay in performance of an agreement for the period that such failure or delay is due to causes beyond its reasonable control Project: QMS21
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forensic testing testing performed for administrative or legal purposes and not for patient care Project: C52, C63
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form a paper or electronic document on which information, data, or results are recorded Project: QMS06, GP26, QMS02, QMS26, QMS25, QMS01 Source: Quality Glossary NOTE: When completed, a form becomes a record.
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formalin-fixed, paraffin-embedded tissue that has undergone a method for preserving cell morphology, as well as nucleic acids and proteins, in a tissue or cytology specimen Project: MM23
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forward angle light scatter measurement of light at a low radial angle relative to the incident light source Alternate Term: FSC, FS, low angle light scatter Project: H42 NOTE: Measured values are a function of the cross sectional area and refractive index of a cell or particle and the wavelength used for measurement. It is commonly used as an estimate of the relative size of a cell or particle.
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forward group tests red blood cells with reagent anti-A and anti-B to determine the red cell antigens present on the red cell Project: I/LA33 NOTE 1: A positive reaction of hemagglutination indicates the presence of the corresponding antigen on red blood cells; a negative reaction (no hemagglutination) indicates the absence of the corresponding red cell antigen; NOTE 2: Formerly known as forward type or front type.
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forward scatter measurement of light at a low radial angle relative to the incident light source Project: H52 NOTE: Measured values are a function of the cross-sectional area and refractive index of a cell or particle and the wavelength used for measurement. It is commonly used as an estimate of the relative size of a cell or particle.
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fosmid a type of cosmid (ie, a hybrid plasmid that contains a lambda phage cos sequence) that is based on the bacterial F-plasmid. These constructs can hold DNA inserts up to 40 kb Project: MM21
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four phases of emergency management four activities that together and sequentially summarize the emergency planning cycle: mitigation, preparedness, response, recovery Project: GP36
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FP the number of false-positive results
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fraction a part of the whole of anything
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fractional carboxyhemoglobin (FCOHb) the substance fraction of carboxyhemoglobin Project: C25, C41
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fractional oxyhemoglobin the oxyhemoglobin substance fraction of the total hemoglobin NOTE 1: Formally termed the oxyhemoglobin fraction of total hemoglobin; NOTE 2: Of the two abbreviated forms of this term, "fractional oxyhemoglobin," or "oxyhemoglobin fraction," the former is the recommended version because it reads, sequentially, identically to the formal symbol. The term "oxyhemoglobin" alone is also acceptable if unambiguous in the context; NOTE 3: "Fractional" and "saturation," or "saturation as % of total hemoglobin," should not be used because of the potential for confusion and awkwardness in phraseology.
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fractionation process undertaken to divide a mixture into multiple components with common characteristics or properties Project: C64
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fragile site a nonstaining gap in the chromatin of a metaphase chromosome, eg, the fragile site at Xq27 in the fragile X syndrome
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fragment analysis electrophoretic analysis of DNA that has been digested with one or more restriction endonucleases Project: MM19
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fragmentation the dissociation of a precursor ion into two or more product ions Project: C64
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frame a subdivision of a message, used to allow periodic communication housekeeping, such as error checks and acknowledgments Project: LIS01
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free fraction the fraction of total analyte not bound to receptor
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free hormone fraction a number between zero and unity indicating what proportion of hormone is in free, nonprotein-bound form Project: C45 NOTE: Alternatively, the free fraction may be expressed as a percentage, which in the case of free T4 leads to more convenient figures.
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free immunoglobulin E human immunoglobulin E that circulates in blood in an unbound state, free of therapeutically administered humanized immunoglobulin G antihuman immunoglobulin E, soluble immunoglobulin E receptors, or other binding factors Project: I/LA20 NOTE: Research assays for free immunoglobulin E that use the alpha chain of the high affinity fragment crystallizable-epsilon receptor receptor as the immunoglobulin E detection reagent have been developed but are not yet commercially available.
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free thyroid hormone index tests all tests in which an estimate of total T4 or total T3 is required Alternate Term: FTI tests Project: C45 NOTE: This definition concerns two distinct categories of tests. First, those in which the total hormone measurement is combined either with a thyroid hormone binding ratio test (eg, T3-uptake) or a measurement of thyroxine binding globulin. This approach leads to indices that correlate with, but cannot be considered as unambiguous estimates of the true free thyroid hormone concentration. The second category comprises techniques like indirect equilibrium dialysis, ultrafiltration, symmetric dialysis, and gel equilibration that may yield valid estimates of the free thyroid hormone fraction so that, after multiplication with the total concentration, a valid approximation of the true free thyroid hormone concentration is obtained. It is recommended to reserve the term “free thyroid hormone index” for the first category of tests only, since it would be rather confusing when at least in theory potential reference measurement procedures would be classified under that name.
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freedom from bias (of a measuring instrument) ability of a measuring instrument to give indications free from systematic error (VIM93)
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frequency the number of occurrences of a given type of event or the number of observations in a specified class (ISO 3534-1/93-2.11) Project: ISO 3534
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frequency distribution the empirical relationship between the values of a characteristic {and/or random variable} and their frequencies or their relative frequencies (ISO3534-1/93-2.15) Project: ISO 3534-1
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frequency distribution the empirical relationship between the values of a characteristic and the frequencies or their relative frequencies Project: ISO 3534
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fresh isolate isolate recovered from a clinical sample within the previous seven days that has not been frozen or subcultured more than five times (ISO 20776-2) Project: ISO 20776-2
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full mutation in trinucleotide repeat disorders, the expanded allele that reaches or exceeds a size threshold such that the abnormal phenotype is expressed, eg, greater than 200 CGG repeats in the fragile X syndrome
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full-scale exercise multiagency, multijurisdictional activity involving actual deployment of resources in a coordinated response as if a real incident had occurred Project: GP36 NOTE 1: A full-scale exercise tests many components of one or more capabilities within emergency response and recovery, and is typically used to assess plans, procedures, and coordinated responses under crisis conditions; NOTE 2: Characteristics of a full-scale exercise include mobilized units, personnel, and equipment; a stressful, realistic environment, and scripted exercise scenarios.
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full-scan acquisition method of mass spectral data acquisition that detects all masses within a specific mass range Project: NBS04, NBS09
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fully automated system a system in which sample and reagent uptake, sample and reagent interaction, chemical and biological analysis, reaction measurement, result interpretation, and result report are mechanized Project: I/LA33
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fume hood See extraction hood.
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function checks activities performed to evaluate critical operating characteristics (eg, stray light, zeroing, electrical levels, optical alignment, background counts, counting efficiency) according to the accepted method of operation for each type of device or instrument Project: QMS13, QMS23 NOTE: Function checks must be within the manufacturer’s established limits before examinations are conducted (42 CFR 493).
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functional exercise activity designed to evaluate capabilities and multiple functions using a simulated response Project: GP36 NOTE 1: A functional exercise is typically used to: evaluate the management of emergency operations centers, command posts, and headquarters; and assess the adequacy of response plans and resources; NOTE 2: Characteristics of a functional exercise include simulated deployment of resources and personnel, rapid problem solving, and a highly stressful environment.
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functional hemoglobin hemoglobin forms in which the iron is in the ferrous (II) state and that can bind reversibly with molecular oxygen components Alternate Term: active hemoglobin, effective hemoglobin
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functional oxygen saturation See oxygen saturation
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functional resolution the size of copy number variant that can be detected in a particular genomic region Project: MM21 NOTE 1: It is dependent upon both the number of probes for a particular copy number variant necessary for a confident detection and the marker density in a given genomic region; NOTE 2: The smallest reliably detected copy number aberration or absence of heterozygosity region for a microarray platform.
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functional sensitivity the measurand concentration at which precision of a measurement procedure, under stated experimental conditions, meets a stated performance requirement Project: EP17 NOTE 1: It is typically determined from a precision profile; NOTE 2: The term “limit of quantitation” with stated requirement for accuracy is recommended.
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fungemia the presence of fungi (ie, yeasts or molds) in the bloodstream Project: M47
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gag multimer an engineered reagent used to identify antigen-specific T-cells that recognize the core protein of HIV Project: I/LA26
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game See exercise Alternate Term: exercise; drill Project: GP36
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gamete donor the donation of an egg or sperm for the intention of achieving a pregnancy NOTE 1: Egg donation is the process by which a woman provides one or several (usually 10–15) eggs for purposes of assisted reproduction or biomedical research. For assisted reproduction purposes, egg donation involves the process of in vitro fertilization, because the eggs are fertilized in the laboratory. After the eggs have been obtained, the role of the egg donor is complete; NOTE 2: Sperm donation refers to provision by a man, known as a sperm donor, of his semen with the intention that it be used to achieve a pregnancy in a woman without the process of sexual fertilization. Pregnancies are most commonly achieved via sperm donation by the use of artificial insemination.
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gamma globulin one of several groups of blood plasma proteins, divided into fractions, based on electrophoretic mobility somewhat slower than beta globulin Project: DI01
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gap analysis a process to determine actions to take to move an entity from its current state to a desired future state Project: QMS19, QMS01 Source: Quality Glossary NOTE 1: Also called need-gap analysis, needs analysis, and needs assessment; NOTE 2: Gap analysis consists of 1) listing of characteristic factors (such as attributes, competencies, performance levels) of the present situation (“what is”), 2) listing factors needed to achieve future objectives (“what should be”), and then 3) highlighting existing gaps that need to be filled.
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gas exchange indices the several quantities that may be used to assess pulmonary gas exchange and intrapulmonary shunting Project: NRSCL08 NOTE 1: These are determined by calculation from both measured and estimated values of other quantities; NOTE 2: The correlation between each of the indices and the shunt fraction, Qsp/Qt is relatively low (r2 < 0.5); NOTE 3: They include: 1) arterial oxygen tension-inspired oxygen fraction ratio - the ratio of the measured tension of oxygen in arterial blood to the fraction of inspired oxygen; 2) alveolar oxygen tension - the partial pressure of oxygen in alveolar gas as estimated by the alveolar air equation; this quantity is required for calculation of some gas exchange indices, such as the oxygen tension gradient and ratio; 3) alveolar-arterial oxygen tension difference (A//aDO2//[PAO2 - PaO2]) - the gradient between the estimated oxygen tension for alveolar air and the oxygen tension measured in arterial blood; 4) arterial-alveolar oxygen tension ratio (PaO2/PAO2//a/A ratio) - the ratio of the oxygen tension as measured in the arterial blood to the estimated oxygen tension in alveolar gas; also designated the a/A ratio, which if unambiguous in context, is acceptable.
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gate a set of parameters used to electronically select particular cells for evaluation Project: I/LA26, H42, H43, H52 NOTE 1: Typically, a region of interest is defined based on one set of parameters (such as forward angle light scatter vs side scatter), and other parameters (such as fluorescence) are evaluated only for cells within that defined region; NOTE 2: Typically, a region of interest is defined based on one set of parameters (such as CD45 vs side scatter), and other parameters (such as fluorescence and light scatter) are evaluated only for cells within that defined region.
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gate an electronic partition by the flow cytometer to select a population of interest for analysis Project: ILA29
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gauging (of a measuring instrument) operation of fixing the positions of the scale marks of a measuring instrument (in some cases of certain principal marks only), in relation to the corresponding values of the measurands (VIM93)
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gel electrophoresis a process that causes separation of molecules in an electric field within a matrix of agarose or polyacrylamide according to size and charge Project: MM02
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gel electrophoresis separation of molecules in an electric field within a matrix of agarose or polyacrylamide according to size and charge Project: MM10, MM12, MM01
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gel electrophoresis separation of molecules, according to size and charge in an electric field within a matrix of agarose or polyacrylamide Project: MM22, MM24
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gene a chromosomal segment that codes for a single polypeptide chain Project: MM02
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gene a chromosomal segment that codes for a single polypeptide chain or a structural molecule Project: MM18
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gene array solid supports on which a collection of gene-specific nucleic acids have been placed at defined locations, either by spotting or direct synthesis. In array analysis, a nucleic acid–containing sample is labeled and then allowed to hybridize with the gene-specific targets on the array Project: MM24 NOTE: See also microarray.
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gene dosage measuring the quantity of a variety of measurands, including DNA, RNA, and protein, by comparison with a known standard; can be used to determine the number of copies of a sequence of DNA (ie, to test for duplication and deletion mutations), either by visual comparison of band intensity or numerical quantification by densitometry Project: MM17 NOTE: If extra copies of a gene are present, intensity is greater than 100% on a gel or film; if one copy of the gene is missing, the intensity is approximately 50%.
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gene panel a group of genes or variants that cause indistinguishable phenotypes and are concurrently sequenced using next-generation sequencing Project: MM09 NOTE 1: The gene panel is sequenced or investigated as a group and generally associated with similar clinical conditions and/or used for similar clinical indications tested in a similar manner; NOTE 2: This definition of “gene panel” refers to a specific phenotype or condition.
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gene rearrangement the normal process by which immunoglobulin genes are assembled into DNA sequences capable of coding for immunoglobulin or T-cell receptor genes Project: MM02 NOTE: Gene rearrangement occurs as a normal part of the developmental maturation of B- and T-lymphocytes.
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gene scanning analysis of DNA by indirect means, as opposed to direct identification by sequencing, aimed at identifying regions of gene sequence alterations NOTE: Scanning is applied as a two-tier process in which a first step (eg, denaturing gradient gel electrophoresis, single-stranded DNA, single-stranded conformation polymorphism [heteroduplex], denaturing high-performance liquid chromatography, temperature gradient capillary electrophoresis, or conformational sensitive gel electrophoresis) identifies a portion of an individual’s gene that differs from a known normal pattern, such as by differences in migration on a gel under specified conditions. This technique can, in pieces (or groups of pieces in a multiplex amplification), cover either the entire coding region or select regions of a gene. Once a region that is different from normal is identified, direct sequencing of a small amplified DNA fragment can localize the specific sequence alteration (base pair substitution, insertion, or deletion).
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gene sequencing process of recording the exact sequence of nucleotides in a given gene fragment Project: NBS05, NBS09
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generator a firm or institution that creates waste Project: GP05
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generic ISI an international sensitivity index determined for a thromboplastin that is not instrument-specific (ie, determined for a group of instruments that uses the same general method for endpoint detection, such as manual, photo-optical, or mechanical methods) Project: H54, H47
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genetic counseling process of helping people understand and adapt to the medical, psychological, and familial implications of genetic contributions to disease. This process integrates the following: 1) interpretation of family and medical histories to assess the chance of disease occurrence or recurrence; 2) education about inheritance, testing, management, prevention, resources, and research; and 3) counseling to promote informed choices and adaptation to the risk or condition Project: MM20
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genetic variant a DNA sequence that varies from a reference DNA sequence Project: NBS05 NOTE 1: In NBS05, “genetic variant” refers to a DNA sequence that varies from a reference DNA sequence in the cystic fibrosis transmembrane conductance regulator (CFTR) region; NOTE 2: Also called “variant” or “CFTR variant.”
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genetically modified organism microorganism that has had its genetic material purposely modified or altered through genetic engineering in a manner that does not occur naturally Project: M29
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genome the complete genetic content of an organism Project: MM13, MM18
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genomic DNA total DNA from an organism or a cell, which includes both the chromosomes within the nucleus and the DNA in mitochondria Project: MM17, MM09
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genomics the study of the genome, which includes genome mapping, gene sequencing, and gene function Project: MM13
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genotype 1) the genetic makeup of an organism or group of organisms, with reference to a single trait, set of traits, or an entire complex of traits (RHUD1.7CD); 2) the specific allelic composition of a gene or set of genes established at the DNA level Project: MM10, MM12, MM01, MM22, MM24
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genotype the genetic makeup of an organism or group of organisms, with reference to a single trait, set of traits, or an entire complex of traits Project: MM09, MM17 NOTE: The specific allelic composition of a gene or set of genes, established at the DNA level.
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genotype phenotype correlation the association between the presence of a certain mutation or mutations (genotype) and the resulting pattern of abnormalities (phenotype)
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genotyping technology that detects small genetic differences and determines differences in genetic complement by comparing a DNA sequence with that of another sample or a reference sequence Project: MM24
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genus rank in taxonomic lineage Project: MM18 NOTE: Genus is one rank higher than species.
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geometric mean the mean of n positive numbers obtained by taking the nth root of the product of the numbers Project: H57 NOTE: A detailed description and an example can be found in CLSI document H47.
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germicide a general term that indicates an agent that kills pathogenic microorganisms on inanimate surfaces Project: I17
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germicide a substance that destroys microorganisms, especially pathogens Project: M29 NOTE: Technically, a germicide does not destroy spores.
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germline the cell line from which the egg or sperm cells (gametes) are derived Project: MM13, MM19 NOTE: A germline variant is the presence of an altered gene within the egg or sperm (germ cell), such that the altered gene can be passed to subsequent generations.
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gestational age time since conception, measured in weeks and days or in completed weeks only Project: NBS10 Source: Newborn Screening Glossary NOTE: The most precise estimate of gestational age is derived from in vitro fertilization information, followed by ultrasonographic metrics, followed by the time from the first day of the last menstrual period.
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gestational age time from the first day of the last menstrual period Project: I/LA25 NOTE: This can be determined directly by asking a woman the date of her last menstrual period (ie, using her “dates”) or indirectly by using an ultrasound scan measurement (usually the crown-rump length or a biparietal diameter). Ultrasound measures that confirm the last menstrual period provide the most accurate assessment of gestational age. Gestational age can be calculated to the day. When tabulated, gestational age is grouped into “completed” weeks; so for example, 16 weeks 0 days to 16 weeks 6 days are all classified as 16 completed weeks.
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gestational age the length of the pregnancy at birth (measured from the first day of the last menstrual period), in completed weeks Project: NBS03, NBS05
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global efficacy a combined level of safety provided by unconditional, conditional, and descriptive safety plus efficacy (ISO Guide 63-2.6)
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Global System for Mobile Communications standard for digital mobile communications, with a capability for international roaming Project: AUTO09 NOTE: Global System for Mobile Communications is operated in the 900-MHz and 1800-MHz frequency bands in Europe and Asia, and in the 800-MHz and 1900-MHz frequency bands in the US. Traditional Global System for Mobile Communications handsets allow data rates of up to 14.4 kbit/s. Some extensions (HCSCD, GPRS) may increase the transfer data rate.
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globulin a group of proteins that occurs in plant and animal tissue, characterized by low solubility in distilled water (as compared with albumin) and increased solubility when salt is added Project: DI01
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glucose level the specific concentration of glucose in the sample matrix specified in the device claim (eg, glucose in interstitial fluid, glucose in capillary blood obtained at a specified anatomical site, or glucose in plasma) Project: POCT05
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glucose meter a small, portable, medical device used for determining the approximate concentration of glucose in the blood at a specific point in time Project: POCT17 NOTE: It can be a component of a blood glucose monitoring system that converts the product of a chemical reaction into the glucose concentration of the sample.
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glucose monitoring the process of measuring glucose in vivo or in vitro over time for the purpose of gathering clinical information Project: POCT05
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glucose monitoring system a combination of an instrument, a disposable element, and ancillary materials such as lancing devices and control solutions used for monitoring glucose levels in blood or other body fluids Project: POCT13, POCT17 NOTE 1: ISO 15197 defines a blood-glucose monitoring system as a “measuring system consisting of a portable instrument and reagents used for the in vitro monitoring of glucose concentrations in blood”; NOTE 2: A system intended for the quantitative measurement of blood glucose as an aid to monitor the effectiveness of glycemic control.
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glycogen principal carbohydrate reserve; glucosan of high molecular weight; found within vacuoles of many of the protozoa Project: M28
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glycohemoglobin (GHB) the generic term for a family of compounds arising from the nonenzymatic reaction between the free aldehyde group of glucose or other sugars and the unprotonated form of the free amino groups of hemoglobin Project: C44 NOTE: The terms "glycated hemoglobin" and "glycohemoglobin" are synonymous.
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glycolysis process by which glucose is converted into lactate with the subsequent formation of ATP (SDELMT84) NOTE: In vitro, this process can lower glucose concentration in a blood sample by the action of red blood cells.
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glycolytic inhibitor agent that inhibits the use of glucose by blood cells Alternate Term: antiglycolytic agent Project: GP39, GP34
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glycoprotein Ib-IX the major platelet membrane receptor for von Willebrand factor Project: H51
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goal (allowable total error) aspirational performance characteristic for allowable total error that may or may not be achievable by currently available testing technology but should be achieved for optimal patient testing Project: EP46
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goal broad statement describing a desired future condition or achievement without describing specific parameters Project: QMS06, QMS16, QMS03, QMS12, QMS01 Source: Quality Glossary NOTE 1: An example is “improve laboratory service”; NOTE 2: “Goal” is not synonymous with “objective.”
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gold standard a nonspecific term that indicates that a process or material(s) is the best available approximation of the truth Project: GP10, I/LA23 NOTE: Its use is deprecated.
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Good Clinical Laboratory Practices a set of guidelines designed to facilitate uniform and consistent data generation and reporting. Good Clinical Laboratory Practices encompasses both quality assurance and quality control principles into its standards
Project: H62
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good laboratory practice a quality system concerned with the organizational process and the conditions under which nonclinical health and environmental safety studies are planned, performed, monitored, recorded, reported, and archived Project: H62
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good laboratory practice embodies a set of principles that provides a framework within which laboratory studies are planned, performed, monitored, recorded, reported, and archived Project: I/LA28 NOTE: These studies are undertaken to generate data by which the hazards and risks to users, consumers, and third parties, including the environment, can be assessed for pharmaceuticals, agrochemicals, cosmetics, food and feed additives, contaminants, novel foods, and biocides. Good laboratory practice helps assure regulatory authorities that the data submitted are a true reflection of the results obtained during the study, and therefore can be relied upon when making risk/safety assessments.
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good-quality spectrum an information-rich spectrum with many well-defined peaks and high signal-to-noise Project: M58
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graded challenge See graded survey Alternate Term: graded event, graded challenge Project: MM14
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graded event See graded survey Alternate Term: graded survey, graded challenge Project: MM14
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graded survey survey/event/challenge in which the participants’ results as a group meet predetermined goals (eg, 80% consensus) and are valid, and from which the individual participant’s performance can be evaluated or scored Alternate Term: graded event, graded challenge Project: MM14
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gram-negative refers to bacteria that do not retain the primary violet stain in the decolorization step in the procedure originally described by Gram Project: GP40
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gram-positive refers to bacteria that absorb and retain the primary violet stain in the decolorization step in the procedure originally described by Gram Project: GP40
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grand mean overall mean calculated after multiple runs or days of analysis Project: EP10, POL1/2
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granulation the quality of being homogeneous NOTE: As applied to blood, it refers to cellular elements.
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granuloma a chronic inflammatory tissue response characterized by activated histiocytes and possibly giant cells Project: M54
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graphical symbol visually perceptible figure used to transmit information independently of language (ISO/IEC 80416-1) Project: ISO/IEC 80416-1, ISO 18113-1
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Graves’ disease hyperthyroidism caused by stimulating autoantibodies directed against the thyroid-stimulating hormone receptor of the thyroid gland Project: NBS10 Source: Newborn Screening Glossary
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gravimetry the process of measuring the mass (weight) of a substance Project: POL1/2
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grind to homogenize by friction (eg, with a sterile mortar and pestle or tissue grinder) Project: M54
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gross square footage square footage that includes usable space and the space necessary to accommodate walls, columns, shafts, plumbing, and other support features Project: QMS04
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grossing station equipment used in the dissection of gross anatomy specimens Project: QMS04
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group purchasing organization an entity that helps health care providers achieve savings and efficiencies by aggregating purchasing volume and using that leverage to negotiate discounts with manufacturers, distributors, and other suppliers Project: QMS21
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growth medium cell culture nutrient solution intended to promote adhesion of dispersed (eg, trypsinized) cells to a culture vessel surface and/or to support mitotic division of cells Project: M41
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growth promotion administration of an antimicrobial, usually as a feed additive, over a period of time to growing animals that results in improved physiologic performance (ie, weight gain, feed conversion) NOTE: Although this has been sometimes referred to as "subtherapeutic" use, it implies only a lower dosage and longer duration of medication than for a therapeutic use of a feed additive.
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guanine-cytosine content the percentage of nitrogenous bases on a DNA molecule that are guanine or cytosine Project: MM22, MM24
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guidelines principles and procedures to set basic requirements; recommended actions
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gypsum board wall or ceiling sheets made from gypsum Project: QMS04 NOTE: Also called "sheet rock."
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hacking a method used to modify a computer program or electronic device in a skillful or clever way, with harmful intent Project: QMS22 NOTE: Hacking may involve the use of software or other devices that allow unauthorized access to computer system information without any interaction with individuals.
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Hamming distance the number of bases that are different between two different sequences, which may be complementary Project: MM09 NOTE: The minimum Hamming distance is the minimum number of bases that need to be different between the two sequences to prevent hybridization of complementary sequences.
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hand hygiene the action of hand cleansing by washing hands with soap and water or a soap solution or by the application of a waterless antimicrobial hand rub (eg, alcohol or chlorhexidine-based hand rubs), to the surface of the hands
Project: POCT04 NOTE: When performed correctly, hand hygiene results in the reduction of microorganisms.
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handling preexamination and postexamination activities involving the specimen Project: PRE04 NOTE: Proper mixing of the specimen collection tube at the time of collection, storing the specimen at an appropriate temperature, allowing sufficient time to clot (for serum specimens), and packaging for transport are forms of handling.
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hands-free describes something operable without the use of a person’s hands Project: QMS04 NOTE: The term is generally used to describe handwash sinks and can include electric-eye operators or foot pedal controls.
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handwash sink a sink that is dedicated to handwashing only and is not used for any procedural purposes Project: QMS04
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hapten a substance with a single epitope that can react with a previously existing antibody but cannot stimulate more antibody production unless combined with other molecules (ie, it is not immunogenic by itself) Project: DI01
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hard ducted describes air ducts that connect directly to an instrument, so fumes or contaminants can be transported directly to the outside of the building Project: QMS04
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hard ionization an ionization process that produces extensive fragmentation Project: C50
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hard stop a clinical decision support tool that cannot be overridden at the point of computerized order entry
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hard wired describes electrical or communication wires directly connected to the unit instead of through an outlet Project: QMS04
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hardware the physical computer equipment, connections, and wiring to connect a communication network Project: POCT02
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hardware token a small physical device that an authorized user of computer services is given to aid in authentication Alternate Term: security token Project: AUTO09 NOTE: The token can also store cryptographic keys and biometric data.
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harm injury or damage to the health of people, or damage to property or the environment (ISO/IEC Guide 51) Project: ISO 14971, EP18, ISO 18113-1, EP23, EP27 NOTE: In EP23 and EP27, damage to property or the environment is considered harmful only if that damage directly harms people.
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harmonization an understanding so as to develop confidence in an acceptance of assessment using different approaches and a willingness to work towards convergence of these methods (WHO) NOTE: Towards this end, harmonization will be addressed as a two-step process: in the short term, to increase/strive for worldwide understanding of various methods used; in the long term, to identify areas for convergence and work toward this convergence (WHO).
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harmonization in glycohemoglobin (GHB) testing, the process by which GHB test results among laboratories are made comparable to a common reference Project: C44
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harmonization the process of recognizing, understanding, and explaining differences while taking steps to achieve uniformity of results, or at a minimum, a means of conversion of results such that different groups can use the data obtained from assays interchangeably Project: I/LA28
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harmonization achievement of equivalent measured quantity values (within clinically meaningful limits) for human samples examined for a stated measurand among two or more in vitro diagnostic medical devices by applying an international consensus protocol in their calibration hierarchies when fit-for-purpose higher-order reference materials or reference measurement procedures are not available Project: EP32 NOTE 1: Harmonization is a calibration hierarchy model used to achieve metrologically traceable quantity values for human samples (ISO 17511); NOTE 2: Harmonization is a special case of non–SI-traceable (International System of Units) standardization in which the calibration of two or more in vitro diagnostic medical devices is traceable to an international harmonization protocol that defines the highest level of metrological traceability for the stated measurand with no traceability to SI; NOTE 3: Harmonized is the condition in which harmonization (equivalence among quantity values) is achieved among two or more in vitro diagnostic medical devices (ISO 21151); NOTE 4: Harmonization is one of the calibration hierarchy models described in ISO 17511 to achieve metrologically traceable quantity values for human samples.
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harmonization reference material reference material used as a calibrator for an international harmonization protocol (ISO 21151) Project: EP32 NOTE: Specifications for these materials are included in the harmonization protocol (ISO 21151).
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hash function an algorithm that computes a value based on a data object (such as a message or file; usually variable-length; possibly very large), thereby mapping the data object to a smaller data object (the “hash result”) which is usually a fixed-size value (RFC 2828) Project: AUTO09
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Hashimoto’s thyroiditis an autoimmune disease that causes chronic inflammation and, frequently, consequential failure of the thyroid gland Project: NBS10 NOTE: Also known as “Hashimoto’s disease.”
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hazard potential source of harm (ISO 15190) Project: ISO 15190, M29, HS11, ISO 18113-1, ISO 18113-2, ISO 18113-3, ISO/IEC Guide 51:1999, ISO/DIS 14971, POCT02, EP18, EP23 NOTE 1: A hazard may harm either a health care provider or a health care recipient (ISO/IEC Guide 51); NOTE 2: Depending on the measurand and the nature and extent of the measurement error, an incorrect in vitro device examination result could be considered a hazard. See ISO 14971 for guidelines.
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hazard for purposes of emergency planning, an occurrence or situation which is both plausible and potentially disruptive of services. See hazard vulnerability analysis Project: GP36
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hazard a dangerous phenomenon, substance, human activity, or condition that may cause loss of life, injury or other health impacts, property damage, loss of livelihoods and services, social and economic disruption, or environmental change Project: POCT16
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hazard analysis study of the chains of cause and effect between identified hazards, the hazardous situations to which they might lead, and the resulting harm Project: EP18 NOTE 1: The purpose of a hazard analysis is to derive sufficient information for the assessment of the risks involved and the identification of preventive measures; NOTE 2: For additional information on hazard analysis, see ISO 14971.
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hazard notice a formal communication that may be distributed from a variety of different sources alerting the public to a possible hazard Project: HS11
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hazard reduction an active or passive process, procedure, or method that reduces or eliminates the hazard of the waste Project: GP05 NOTE: Examples include storing radioactive waste for decay, autoclaving infectious waste, and neutralizing waste mineral acids.
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hazard statement phrase assigned to a hazard class and category that describes the nature of the hazard or hazards (see A Guide to the Globally Harmonized System of Classification and Labelling of Chemicals [GHS]) Project: GP17
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hazard vulnerability analysis an analysis of the various risks or emergencies likely to be experienced by a community, facility, or laboratory, and the severity of impact potentially resulting from each Project: GP36 NOTE: An emergency operations plan should be developed in response to a hazard vulnerability analysis.
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hazardous material any substance that poses an immediate or potential threat to human health or to the environment, and that requires special handling, processing, or disposal because it is toxic, infectious, carcinogenic, explosive, or reactive Project: ISO 14971, QMS28 NOTE: Hazardous wastes, regulated medical wastes, and most forms of low-level radiactive waste are hazardous materials.
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hazardous material as referenced in Department of Transportation regulations, a substance or material that has been determined by the Secretary of Transportation to be capable of posing an unreasonable risk to health, safety, and property when transported in commerce, and which has been so designated Alternate Term: HAZMAT Project: GP05 NOTE: Hazardous wastes, regulated medical wastes, and most forms of low-level radioactive waste are hazardous materials.
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hazardous situation circumstance in which people, property, or the environment are exposed to one or more hazards (ISO/IEC Guide 51) Project: ISO 18113-1, ISO 18113-2, ISO 18113-3, ISO/IEC Guide 51, ISO/DIS 14971, EP18 NOTE: Incorrect in vitro diagnostic examination results can contribute to a hazardous situation for a patient. See ISO 14971:2007, Annex H (ISO 18113-1).
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hazardous waste waste that is potentially harmful to human beings, property, or the environment (ISO 18113-1) Project: ISO 15190, ISO 18113-1, ISO 18113-2, ISO 18113-3, QMS28 NOTE 1: Includes waste that is flammable, combustible, ignitable, corrosive, toxic, reactive, injurious, or infectious (ISO 18113-1); NOTE 2: Regulated hazardous waste is chemical waste that singly, or in combination, poses an immediate or potential threat to human health or to the environment and that, singly or in combination, requires special handling, processing, or disposal; NOTE 3: This includes chemical wastes that might be flammable, explosive, reactive, corrosive, toxic, carcinogenic, infectious, bioconcentrative, potentially lethal, irritating, or strongly sensitizing; EXAMPLES: Used reagent strips contaminated with human blood; reagent solution containing sodium azide; decommissioned instruments containing heavy metals (ISO 18113-1).
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hazardous waste regulated hazardous waste is chemical waste that singly, or in combination, poses an immediate or potential threat to human health or to the environment and that, singly or in combination, requires special handling, processing, or disposal Project: GP05 NOTE: This includes chemical wastes that may be flammable, explosive, reactive, corrosive, toxic, carcinogenic, infectious, bioconcentrative, potentially lethal, irritating, or strongly sensitizing.
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hazardous waste waste that is potentially flammable, combustible, ignitable, corrosive, toxic, reactive, or injurious to people or the environment (ISO 15190) Project: M29
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hazards and operability study risk analysis method based on guidewords used for the proactive investigation of failure conditions within a system or device (IEC 61882) Alternate Term: HAZOP Project: POCT02
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HAZMAT See hazardous material Project: GP05
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HAZMAT employee as referenced in Department of Transportation regulations, a person who is employed by a HAZMAT employer and directly affects hazardous materials (HAZMAT) transportation safety, including an owner-operator of a motor vehicle that transports HAZMAT; and any other employed person (including a self-employed person) who loads, unloads, or handles HAZMAT; tests, reconditions, repairs, modifies, marks, or otherwise represents packagings as qualified for use for the transportation of HAZMAT; prepares HAZMAT for transportations; is responsible for safety of transporting HAZMAT; or operates a vehicle used to transport HAZMAT Project: GP05
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HAZMAT employer as referenced in Department of Transportation regulations, a person who uses one or more of its employees in connection with transporting HAZMAT in commerce; causing HAZMAT to be transported or shipped in commerce; or representing, marking, certifying, selling, offering, reconditioning, testing, repairing, or modifying packagings as qualified for the use in transportation of HAZMAT Project: GP05
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Hb See hemoglobin
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HDL cholesterol cholesterol bound to a high-density lipoprotein
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health care application software application used for clinical patient care that contains patient information Project: AUTO14 NOTE 1: Such software typically contains an application programming interface that allows an end user to interact with information in a local or remote database; NOTE 2: Health care applications include instrument software, testing device software, middleware, and laboratory information system software
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health care delivery organization an organization, or group of related organizations, involved with the delivery of health care services Project: AUTO11 NOTE: A hospital is an example of a health care delivery organization, as are a group of physician practices acting in concert in an area.
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health care provider individual authorized to deliver health care to a patient (ISO 17593) Project: ISO 17593, GP33, POCT08, PRE05, PRE01, GP23, POCT15 NOTE 1: A health care provider is an individual, such as a doctor, nurse, technician, technical specialist, or appropriate assistant, who provides instruction to a self-testing patient (ISO 17593); NOTE 2: This is a global term used to describe a person obtaining the specimen or sample and can include physicians, nurses, laboratorians, respiratory therapists, care assistants, and phlebotomists.
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health care provider individual authorized to deliver health services to a patient (ISO 18113-1) Project: ISO 18113-1, ISO 18113-2, ISO 18113-3 EXAMPLES: physician, nurse, ambulance attendant, dentist, diabetes educator, laboratory technician, medical assistant, medical specialist, respiratory care practitioner (ISO 18113-1).
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health care provider health care professional, usually in the community, who provides basic health care for an individual Project: NBS03
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health care provider health care professional (eg, primary care provider, neonatologist, pediatrician, disease specialist) who provides health care for an individual
Project: NBS09, NBS02, NBS05, NBS10 NOTE: See primary health care provider and specialty care provider.
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health information exchange the electronic sharing of health-related information among organizations within a region, community, or hospital system according to nationally recognized standards
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Health Level 7 the Health Level 7 organization (www.hl7.org), an American National Standards Institute–accredited standards development organization focused on messaging to support the exchange of clinical and administrative health care data Project: POCT01 NOTE: The Health Level 7 standard specifies a transport-independent messaging framework and structure that enables disparate health care information systems to exchange data.
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Health Level 7 an American National Standards Institute–accredited standards development organization focused on messages that support the exchange of clinical data (www.hl7.org) Alternate Term: HL7 Project: POCT02 NOTE: The Health Level 7 standard specifies a message framework and structure that enables disparate health care information systems to exchange data.
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Health Level Seven the highest level (application) communications model for open systems interconnection Project: AUTO01, AUTO07, AUTO02, AUTO03 NOTE: Level 7 supports security checks, participant identification, availability checks, exchange mechanism negotiations, and data exchange structuring.
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Health Level Seven International (HL7) an international standard for interfaces used in health care Alternate Term: HL7 International Project: AUTO14
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health services research the multidisciplinary field of scientific investigation that studies how social factors, financing systems, organizational structures and processes, health technologies, and personal behaviors affect access to health care, the quality and cost of health care, and ultimately our health and well-being Project: GP45 NOTE: Its research domains are individuals, families, organizations, institutions, communities, and populations.
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Healthcare Informatics Standards Board an organization that coordinates activities of all standards developers in the healthcare informatics area of American National Standards Institute organizations Project: AUTO01, AUTO07, AUTO02
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Healthcare Information Technology Standards Panel an organization that coordinates activities of all standards developers in the health care informatics area of American National Standards Institute organizations (http://www.hitsp.org/) Project: AUTO03
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heat-induced antigen retrieval the process of antigen retrieval mediated by heating the tissue section, on a slide in a buffer Project: I/LA28 NOTE 1: Heat sources include water baths, steamers, pressure cookers, autoclaves, and microwave ovens. Buffers include an agent such as citrate, at a specified pH (commonly neutral [pH 6-7] or high pH [pH 9-11]), and may include detergents or chelators such as EDTA or ethylene glycol tetraacetic acid; NOTE 2: See antigen retrieval.
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heavy polypeptide chain a polypeptide with a molecular mass of about 50,000 Daltons Project: NRSCL08 NOTE 1: When paired with another heavy chain and linked to two light chains, it forms the immunoglobulin molecule; NOTE 2: The heavy chains of the IgA, IgD, IgE, IgG, and IgM immunoglobulins are denoted, respectively, as alpha, delta, epsilon, gamma, and mu chains.
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helical cone beam computed tomography See spiral cone beam computed tomography Project: H59
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HELLP syndrome a life-threatening pregnancy complication considered a variant of preeclampsia with features including Hemolysis, Elevated Liver enzymes, and Low Platelets (HELLP) Project: NBS03 NOTE: HELLP syndrome occurs in approximately 10% of pregnant women with preeclampsia or eclampsia.
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helminth may refer to a nematode (roundworm), cestode (tapeworm), or trematode (fluke) Project: M28
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hemadsorption adherence of certain red blood cells to the surface of monolayered cells Project: m41 NOTE: Hemadsorption is mediated by expression of viral hemagglutinin proteins on the surface of cells infected by certain viruses (eg, influenza) and can occur in the absence of cytopathic effect.
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hemagglutination in viral culture, the clumping of certain red blood cells that can be observed in culture supernatants containing hemagglutinin proteins shed by cells infected by certain viruses (eg, influenza) Project: M41
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hemagglutination 1) the clumping of red blood cells; 2) agglutination reactions using erythrocytes. (Cf. DI1)
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hematocrit the measure of the ratio of the volume occupied by the red blood cells to the volume of whole blood, expressed as a fraction or percentage Project: POCT13, POCT17
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hematocrit effect the influence of hematocrit on the ability for the device to obtain an accurate result Project: POCT07
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hematoma localized collection of extravasated blood, usually clotted, in an organ, space, or tissue, usually due to a break in the wall of a blood vessel (Dorland's Illustrated Medical Dictionary. 33rd ed. Elsevier, Inc.; 2019) Project: PRE02
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hematopoietic cell transplantation a term adopted by the Primary Immune Deficiency Transplant Consortium that refers to the intravenous infusion of hematopoietic cells collected from bone marrow, peripheral blood, or umbilical cord blood of a living related or unrelated donor to reconstitute hematopoietic function in patients with damaged or defective bone marrow or immune systems Project: NBS06 NOTE 1: Alternatively referred to as a “hematopoietic stem cell transplant”; NOTE 2: Peripheral blood cells collected for transplant are enriched through positive selection to increase the relative proportion of potential pluripotent stem cells capable of developing into normal hematopoietic (blood) cells; NOTE 3: Hematopoietic cell transplantation is a recommended treatment for severe combined immunodeficiency and many other primary immunodeficiencies.
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hematopoietic stem cells stem cells that give rise to other blood cells through hematopoiesis, which occurs in the red bone marrow in the core of most bones Project: NBS09
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hemiglobin hemoglobin in which the iron atoms have been oxidized to the ferric state and which has then been bonded with cyanide ions Alternate Term: methemoglobin, ferrihemoglobin Project: H15
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hemiglobincyanide hemoglobin in which the iron atoms have been oxidized to the ferric state and which has then been bonded with cyanide ions Alternate Term: cyanmethemoglobin, cyanferrihemoglobin, methemoglobincyanide Project: H15
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hemizygous describes an individual who has only one member of a chromosome pair or chromosome segment rather than the usual two; refers in particular to X-linked genes in males who, under usual circumstances, have only one X chromosome or individuals who have a deletion at corresponding loci on one of the homologous chromosomes Project: MM17
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hemodialysis a procedure used to remove toxic substances from blood in patients with severe renal failure Project: POCT14
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hemoglobin the iron-containing red pigment-protein of erythrocytes Alternate Term: Hb; Hgb Project: POCT11 NOTE: Hemoglobin occurs most commonly with the iron in the ferrous (II) state in two forms: deoxygenated (deoxyhemoglobin, HHb) and oxygenated (oxyhemoglobin, O2Hb), which work in concert to transport oxygen to and from the tissues.
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hemoglobin A1c hemoglobin that is irreversibly glycated at one or both N-terminal valines of the beta-chains and is a major component of glycohemoglobin Alternate Term: HbA1c Project: C44
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hemoglobin derivatives a hemoglobin type characterized by the heme-iron portion of the molecule Project: C25
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hemoglobin oxygen saturation the amount of oxyhemoglobin in blood expressed as a (percent) fraction of the total amount of hemoglobin able to bind oxygen (ie, oxyhemoglobin plus deoxyhemoglobin) Project: C46
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hemoglobin variant a hemoglobin type is characterized by the protein moiety of the molecule Project: NRSCL08 NOTE: Most specifically by the difference from hemoglobin A1. (Cf. C25)
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hemoglobinometer a photometer whose measurement scale has been calibrated directly in units of hemoglobin concentration Project: H15
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hemoglobinopathy an inherited blood disorder characterized by the presence of a structural hemoglobin variant or a quantitative difference in globin chain production Project: NBS08
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hemoglobin-oxygen binding capacity the maximum amount of oxygen that can be carried by the hemoglobin in a given quantity of blood Alternate Term: BO2 Project: NRSCL08 NOTE: This is represented by: BO2 = [ctHb - (cdysHb)] · bO2, where bO2 = 1.39 mL/g and cdysHb is the concentration of dysfunctional or inactive hemoglobin.
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hemoglobins all those hemoglobin derivatives normally present in circulating blood. They include deoxyhemoglobin, oxyhemoglobin, carboxyhemoglobin, and hemiglobin (methemoglobin). Please see the current edition of CLSI/NCCLS document C46—Blood Gas and pH Analysis and Related Measurements for more detailed information Project: H15
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hemolysate the product that results from the lysis of whole blood Project: H09 NOTE: See also erythrolysate.
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hemolysis the breaking down of red blood cells with liberation of hemoglobin (RHUD-1.7CD) Project: C37
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hemolysis the breakdown of red blood cells in serum or plasma, which frees the hemoglobin from the cells and creates a reddish tinge Project: POCT04 NOTE: Hemolysis interferes with some laboratory tests.
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hemolysis the breakdown of erythrocytes in blood, which frees the hemoglobin and intracellular contents from the cells Project: C56 NOTE: Serum or plasma prepared from hemolyzed blood has visible red color when released hemoglobin exceeds 200 mg/L (20 mg/dL). The serum or plasma concentrations of other abundant red cell components such as potassium, phosphate, and lactate dehydrogenase also may be increased.
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hemothorax as a subtype of pleural fluid, blood in the pleural space due to direct hemorrhage from an interrupted blood vessel
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heparin (unfractionated) a mixture of complex glycosaminoglycans (mucopolysaccharides) of widely varying molecular weight (5000 to 50 000 Da) derived from animal tissues, used for prevention and treatment of venous and arterial thrombosis Project: POCT14
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heparin a polysaccharide characterized by its anticoagulant properties Project: NRSCL08, H47 NOTE: There are a variety of heparin “types,” which have different affects on the activated partial thromboplastin time and prothrombin time coagulation tests. Unfractionated heparin is a class of intravenous drugs that indirectly (through antithrombin) inhibit the enzymes thrombin and to some extent, factor Xa. The activated partial thromboplastin time is proportionately prolonged in the presence of unfractionated heparin. Low molecular weight heparin is a class of heparin drugs consisting of smaller, more uniform-sized heparin molecules that inhibit mainly factor Xa, and minimally, and not in a dose-dependent manner, affect the activated partial thromboplastin time. Pentasaccharide is a heparin analog of five heparin subunits that inhibits factor Xa and only marginally affects the activated partial thromboplastin time.
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heparinized specimens anticoagulated with a heparin salt(s) Project: C29
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hertz the derived standardized international (SI) units of inductance, defined as the frequency of one cycle per second, having units of S-1 (reciprocal seconds) Project: GP28
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heterocytotropic that which attaches to other kinds of cells Project: DI01
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heteroduplex analysis electrophoretic technique in which the DNA to be analyzed is first heated and allowed to cool slowly to allow base pairing among the DNA fragments present Project: MM05 NOTE: These annealed products are separated by nondenaturing gel electrophoresis, in which fragments will be separated by both size and DNA sequence composition.
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heterogeneic with a different genetic constitution Project: DI01
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heterogeneous immunoassay an immunoassay that requires the physical separation of free labeled antigen (or antibody) from the labeled antigen (or antibody) bound in an immune complex before measurement of the quantity of label (Cf. DI1) Project: DI01, I/LA23
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heterogeneous immunoassay an immunoassay that requires one or more steps to separate the bound from the free indicator Project: H59
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heterologous derived from another species Project: DI01
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heterologous interpolation a calibration scheme in which the standard or reference (calibration) dose-response curve is constructed using reagents that have a different (heterologous) specificity from those being used to measure the analyte of interest Project: I/LA34, I/LA20 NOTE 1: This assay involves the performance of two (or more) simultaneously performed assays with different sets of reagents. The first is the calibration portion of the assay that can be illustrated by a total serum immunoglobulin E standard (calibration) curve. The second portion of the assay involves the measurement of immunoglobulin E antibody to a defined allergen specificity (eg, Ambrosia artemisiifolia, common/short ragweed). Once the analyte (immunoglobulin E) is bound in both the calibration and antibody detection sections of the assay, the same conjugated, antihuman immunoglobulin E detection reagent is added to both. The response results (counts per minute–bound, optical density, fluorescence signal units) generated in the immunoglobulin E anti-short ragweed portion of the assay are interpolated from the (heterologous) total serum immunoglobulin E calibration curve in international units per milliliter (IUA/mL) or mass units per milliliter (ng/mL) of immunoglobulin E, which are calibrated back to an immunoglobulin E primary reference standard. Parallelism between the heterologous calibration curve and dose-response curve of test specimens analyzed at multiple dilutions is a requirement for the successful use of the heterologous interpolation calibration scheme; NOTE 2: Parallelism between the heterologous calibration curve and dose-response curve of test specimens analyzed at multiple dilutions is a requirement for the successful use of the heterologous interpolation calibration scheme.
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heterophil term applied to antigens that occur in more than one species of animal and that may be immunologically related to antigens also found in plants or microbes Project: DI01
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heterophile antibodies antibodies produced against poorly defined antigens that react with immunoglobulins from two or more species Project: I/LA30
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heterophile antibody antibody produced against poorly defined antigens that react with immunoglobulins from two or more species, or exhibit rheumatoid factor activity and bind to the Fc portion of human or animal immunoglobulins Project: H59
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heterophilic antibodies antibodies in test sera that can bind to immunoglobulins from other species (eg, human antimouse immunoglobulins) NOTE: The observed reactivity may be specific, as seen with sera from animal handlers or subjects that have received a therapeutic monoclonal antibody drug or immune serum, or nonspecific as a result of human autoantibody cross-reactivity (eg, rheumatoid factor). In either case, these heterophile antibodies can induce false-positive or false-negative clinical test results depending on the assay design.
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heterophilic antibody an antibody that has an affinity for an antigen other than its specific antigen Alternate Term: heteroantibody
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heteroresistance presence of two or more mycobacterial populations of a strain with different drug susceptibilities Project: M24 NOTE: Heteroresistance is expected when drug resistance is emerging during inadequate therapy.
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heteroresistance presence of preexisting subpopulations of microbial cells exhibiting higher levels of resistance toward an antimicrobial agent while the majority of the cell population within the same culture is phenotypically susceptible to the same antimicrobial agent Project: M02, M07
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heteroscedasticity changes in the variability of a measurement procedure due to changes in the measurand level Project: EP14 NOTE: For example, when the standard deviation is significantly greater at the high end versus the low end of a measuring interval.
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heterospecificity describes an antiserum with reactivity against a variety of antigens Project: NRSCL08
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heterotropic characteristic of tissues grafted into a site that is anatomically different from its site in the donor Project: DI01
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heterozygosity the presence of two different genotypes (single nucleotide polymorphisms) at a locus Project: MM21
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heterozygous having the two alleles at corresponding loci on homologous chromosomes different for one or more loci Project: MM17, MM09, NBS09 NOTE: In NBS09, “heterozygous” is used rather than “carrier” to describe females who have one variant in the ABCD1 gene, because “carrier” usually denotes that the individual will not be affected by a disease, which is not true for women who are heterozygous for adrenoleukodystrophy.
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heterozygous two genes at corresponding loci on homologous chromosomes having different nucleic acid sequences Project: MM19
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Hgb See hemoglobin.
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HHS abbreviation for the (US) Department of Health and Human Services, or its designee (US CFR 493 February 28, 1992)
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high-complexity testing laboratory tests in which the risk of erroneous results is high due to complicated reagent preparation, complex equipment, complicated troubleshooting, and maintenance NOTE: Test performance and interpretation of results requires extensive knowledge of factors that could influence test results.
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high-density storage system storage shelving that is stacked together in several rows with one or two aisles Project: QMS04 NOTE: Units are moved to create access aisles as needed.
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high-efficiency particulate air filter used to remove from the air 99.97% of particulates having a diameter of 0.3 μm Project: QMS04
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high-level protocol a protocol describing the content of messages passed between systems Project: AUTO01, AUTO02, AUTO03
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high-performance liquid chromatography an analytical technique for performing chromatographic separations of organic compounds in which the eluent, or carrier, is a liquid under pressure Alternate Term: HPLC
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Hill coefficient in pharmacokinetic/pharmacodynamic modeling, refers to the slope of the dose or exposure-response curve. The larger the value, the steeper the slope Project: M23
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HIPAA the acronym for the Health Insurance Portability and Accountability Act of 1996 NOTE: The Administrative Simplification provisions of the Health Insurance Portability and Accountability Act of 1996 (HIPAA, Title II) require the Department of Health and Human Services to establish national standards for electronic healthcare transactions and national identifiers for providers, health plans, and employers. It also addresses the security and privacy of health data.
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HIS the computer system used for management of data collected and generated by various services, laboratories, and facilities served by a hospital Project: AUTO01
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HIS abbreviation for Hospital Information System Project: AUTO02, AUTO03
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HIS (hospital information system) the computer system used for management of data collected and generated by various services, laboratories, and facilities served by a hospital Project: AUTO10
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HISB abbreviation for Healthcare Informatics Standards Board Project: AUTO02
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histochemical stain stain performed on a tissue specimen to aid in visualizing structures, including fungi Project: M54
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histogram a graph of a frequency distribution in which rectangles on the horizontal or x-axis are given widths proportional to the intervals of the quantities being displayed, and heights proportional to the frequency of occurrence of quantities within that interval Project: NRSCL08
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histogram See single-parameter display Alternate Term: single-parameter display Project: H52
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histogram channel number the ordinal number beginning at zero that represents the relative position of a particular bin in a histogram Project: I/LA24 NOTE: When analog signals are digitized, the histogram channel number represents the relative strength of the original analog signal.
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histomorphology the cellular and architectural (eg, stromal, epithelial) features of a tissue Project: I/LA28 NOTE: As used in immunohistochemistry, it is the cell-type localization of the antibody-antigen reaction.
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hit rate proportion of the number of examination results from a sample that are declared positive Project: EP12
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hit rate proportion of the number of measurement results deemed to indicate presence of a measurand (positive detection result) to the total number of measurement results obtained Project: EP17
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HITSP abbreviation for Healthcare Information Technology Standards Panel Project: AUTO03
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HIV seroreversion reversal of a confirmed HIV serological test result from positive to negative (loss of detectable antibody) Project: M53
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HL7 abbreviation for Health Level Seven Project: AUTO01, AUTO02, AUTO03
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homebrew assay in the United States, a term that refers to an in vitro diagnostic that is a laboratory-developed test using separately purchased reagents that are not assembled in a kit and are without instructions for use from the manufacturer of the reagents Project: I/LA28 NOTE: The analytical and clinical performance characteristics of the finished assay are the responsibility of the laboratory director.
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homeostasis state of equilibrium of the internal body Project: GP48
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homo a combining form that denotes “like” Project: DI01
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homocytotropic characteristic of antibodies that attach specifically to certain kinds of cells in the same species as that in which they are made Project: DI01
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homogeneity the condition of being of uniform structure or composition with respect to one or more specified properties Project: C37, EP30 NOTE: The converse of homogeneity is known as “heterogeneity.”
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homogeneous simultaneous amplification of the target and detection of the product in which data collection occurs throughout the process Alternate Term: kinetic “real-time” assay Project: MM06
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homogeneous immunoassay an immunoassay in which no separation step is performed; an immunoassay that requires only the mixing of a sample (analyte) and immunochemical reagents (antibodies or antibody conjugates) with no wash step(s) to disturb the binding equilibrium before the bound fraction is measured Project: I/LA23 NOTE: The measurand (analyte) must produce a detectable dose-response signal upon binding that distinguishes it from unbound analyte.
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homogeneous immunoassay an immunoassay that does not require a step for the separation of the bound and free indicator Project: H59
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homogeneous polymerase chain reaction polymerase chain reaction and amplicon detection performed in a single tube without an intervening separation or wash step NOTE: Detection can be performed with specific reagents, such as molecular beacons. This is in contrast to heterogeneous polymerase chain reaction, in which the polymerase chain reaction amplicons are separated from amplification reagents before detection, usually by electrophoresis.
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homogeneous, kinetic polymerase chain reaction See real-time polymerase chain reaction Alternate Term: real-time polymerase chain reaction Project: MM03
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homogenization the process by which high-molecular-weight genomic DNA and other high-molecular-weight cellular components are sheared to create a homogenous lysate; it is necessary to reduce the viscosity of the cell lysates created by disruption before final isolation Project: MM13 NOTE: Incomplete homogenization results in inefficient binding of DNA and/or RNA and therefore significantly reduced yields during purification.
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homogenize to reduce a patient sample to a small, uniform size dispersed in a liquid Project: M54
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homologous derived from an animal of the same species Project: DI01
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homologous interpolation a calibration scheme in which the standard or reference (calibration) dose-response curve is constructed using reagents that have the same (homologous) specificity from those being used to measure the analyte of interest Project: I/LA34, I/LA20 NOTE 1: In this assay, both the calibrator and test specimens are analyzed using the identical assay reagents; NOTE 2: In an assay that measures ragweed-specific immunoglobulin E antibody, for instance, the calibration curve is constructed with multiple dilutions of a serum containing a predefined amount of ragweed-specific immunoglobulin E antibody. Test sera are simultaneously analyzed using the same reagents for immunoglobulin E antiragweed. When complete, the response results (counts per minute–bound, absorbance, fluorescence signal units) generated for the test sera are interpolated from the immunoglobulin E antishort ragweed calibration curve that has been precalibrated in arbitrary units or mass units per volume (eg, ng/mL). Depletion analysis, with or without elution, can be used to prepare an immunoglobulin E antibody reference serum that has an assigned mass/volume quantity of allergen-specific immunoglobulin E antibody; NOTE 3: Homologous interpolation is the conventional calibration scheme used by most clinical immunoassays; however, it has been rarely applied to immunoglobulin E antibody assays, because large amounts of serum-containing immunoglobulin E antibodies of all clinically relevant specificities are difficult to prepare. Moreover, because epitope specificities are rarely defined and they may differ with respect to the reference and test sera, homologous interpolation within the context of immunoglobulin E assays is impractical.
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homozygous having the two alleles at corresponding loci on homologous chromosomes identical for one or more loci Project: MM17, MM19, MM09
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horizontal exit route used to escape a fire that moves in a horizontal direction, such as a direct route to the outside or into another building through a fire-rated wall
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hospital disinfectant a US Environmental Protection Agency-registered agent with demonstrated effectiveness against Staphylococcus aureus, Salmonella choleraesuis, and Pseudomonas aeruginosa and may also be effective against specifically named organisms such as Mycobacterium tuberculosis, pathogenic fungi, or certain viruses Project: M29
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hospital information system a data management system that usually supports functions external to the laboratory, eg, admission, discharge, and transfer functions Project: AUTO02, AUTO03
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hospital information system the computer system used to manage data collected and generated by various services, laboratories, and facilities served by a hospital/health care system Alternate Term: health care information system Project: I/LA33, POCT07
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hospital/health care information system the computer system used to manage data collected and generated by various services, laboratories, and facilities served by a hospital or a health care system Project: M39
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hot zone the site of an overt incident of any type
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housekeeping proteins proteins that are constitutively expressed under all physiological conditions and are important for maintaining basic cellular function Project: M58
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human factors engineering interdisciplinary approach for evaluating and improving the safety, efficiency, and robustness of work systems NOTE: Human factors engineering addresses multiple aspects of work, including task analysis and design; device evaluation and usability; communication, collaboration, and teamwork; training; and systems resilience, adaptation, and failure.
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human papillomavirus the most common sexually transmitted virus and causative agent in the pathogenesis of cervical cancer and its precursor lesions in almost all cases Alternate Term: HPV Project: GP15
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humoral immunity immune responses that involve secretion of specific antibodies produced by B-cells Project: NBS06
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hybrid anything derived from heterogeneous sources, or composed of heterogeneous elements Project: NRSCL08
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hybridization base pairing of complementary strands of nucleic acid by hydrogen bond formation; the binding of probe to specific nucleic acid sequences or amplification products Project: NRSCL08, MM10, MM12, MM01, MM22, MM24 NOTE 1: Hybridization can be performed with both nucleic acid target and probe in solution or with the nucleic acid target retained within a tissue specimen; this latter form of hybridization is referred to as “in situ hybridization”; NOTE 2: Hybridization can be performed with both nucleic acid target and probe in solution, with nucleic acid target attached to a solid support, or with either one bound to a solid support such as a microtiter plate or membrane; NOTE 3: Hybridization can be performed with both nucleic acid target and probe in solution, or with either one bound to a solid support such as a microtiter plate, glass, or membrane.
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hybridization a base pairing of complementary strands of nucleic acid by hydrogen bond formation; the binding of probe to specific nucleic acid sequences or polymerase chain reaction amplification products Project: I/LA28, MM09 NOTE: Hybridization can be performed with both nucleic acid target and probe in solution or with either bound to a solid support, such as a microtiter plate, glass, or membrane.
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hybridoma a cell made in the laboratory by fusing a normal cell with a cancer cell to combine certain features of each Project: NRSCL08 NOTE: Most specifically, a cell line derived by the fusion of a B cell and a plasmacytoma cell, usually for the production of monoclonal antibodies.
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hydrolysis probe in real-time polymerase chain reaction, during the primer extension step, Thermus aquaticus polymerase with a 5´–3´ exonuclease activity cleaves a fluor/quencher-labeled probe hybridized to the complementary target sequence. As in other real-time polymerase chain reaction methods, the resulting fluorescence signal permits quantitative measurements of the accumulation of the product during the exponential stages of the polymerase chain reaction Project: MM19
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hyperacute rejection a severe, nonreversible rejection of transplanted tissue that is mediated by preformed antibody response Project: ILA29
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hyperglycemia high blood glucose levels or blood glucose higher than the target range for the patient Project: POCT13 NOTE: Blood glucose may be considered “high” at various glucose concentrations, eg, greater than 140 mg/dL (7.8 mmol/L), 160 mg/dL (8.9 mmol/L), or 180 mg/dL (10 mmol/L), for different clinical settings in different publications.
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hyperglycemia threshold glucose level that is considered high as determined by the clinician Project: POCT05 NOTE: The hyperglycemia threshold does not need to be the same as the alert threshold for hyperglycemia.
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hyperglycemic event an instance or instances in which the glucose level is at or above the hyperglycemia threshold Project: POCT05 NOTE: Multiple glucose levels above the hyperglycemic threshold during this interval are considered a single hyperglycemic event.
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hypersensitivity reactions undesirable (ie, damaging, discomfort-producing, and sometimes fatal) reactions produced by the normal immune system. Hypersensitivity reactions require a presensitized (immune) state of the host
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Hypertext Transfer Protocol a Transmission Control Protocol–based, application-layer, client-server, Internet protocol used to carry data requests and responses in the World Wide Web (RFC 2828) Project: AUTO09
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hyperthyroidism excess of thyroid hormone, usually due to the overproduction of thyroid hormone by the thyroid gland Project: NBS10 Source: Newborn Screening Glossary NOTE: Also called “overactive thyroid.”
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hyperthyrotropinemia a biochemical pattern of elevated serum thyrotropin (ie, thyroid-stimulating hormone) levels accompanied by in-range thyroid hormone levels Project: NBS10 Source: Newborn Screening Glossary
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hypertrypsinogenemia an elevated concentration of trypsinogen in blood specimens, as in the dried blood spot specimens obtained from newborns Project: NBS05 NOTE: The meaning of “elevated health care professional (eg, primary care provider, neonatologist, pediatrician, disease specialist) who provides health care for an individual” varies depending on the immunoreactive trypsinogen method used and the cutoff value selected.
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hypha (pl. hyphae) a septate or aseptate filament of a fungus Project: M54
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hypoglycemia an abnormally low level of glucose in the blood (eg, blood glucose concentration below 70 mg/dL [3.9 mmol/L]) Project: POCT13, POCT17
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hypoglycemia threshold glucose level that is considered low as determined by the clinician Project: POCT05 NOTE: The hypoglycemia threshold does not need to be the same as the alert threshold for hypoglycemia.
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hypoglycemic event an instance or instances in which the glucose level is at or below the hypoglycemia threshold Project: POCT05 NOTE: Multiple glucose levels below the hypoglycemic threshold during this interval are considered a single hypoglycemic event.
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hypothesis 1) in a trial, a statement relating to the possible different effect of the interventions on an outcome; 2) a supposition, arrived at from observation or reflection, that leads to refutable predictions Project: GP45 NOTE 1: The null hypothesis of no such effect is amenable to explicit statistical evaluation by a hypothesis test, which generates a P-value.
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hypothesis testing in Statistics, the testing of two or more statistical hypotheses that are mutually exclusive so that exactly one hypothesis can be accepted at a specified confidence level Project: NRSCL08
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hypothyroidism disease of the endocrine system in which the thyroid gland fails to produce sufficient thyroid hormone to meet the metabolic demands of the body Project: NBS10 Source: Newborn Screening Glossary NOTE 1: Also called “underactive thyroid”; NOTE 2: See primary congenital hypothyroidism, central congenital hypothyroidism, subclinical congenital hypothyroidism, and transient congenital hypothyroidism.
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hypothyroxinemia low total thyroxine levels commonly observed in preterm, low birth weight, or sick newborns in the absence of elevated thyroid-stimulating hormone and not due to central congenital hypothyroidism Project: NBS10 Source: Newborn Screening Glossary
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iatrogenic anemia a condition of lowered hematocrit and hemoglobin count resulting from large or frequent removal of blood specimens, usually for laboratory testing Project: GP42, GP48, PRE02
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IC50 concentration of antiviral agent that inhibits virus production by 50% as measured, for example, by plaque formation, DNA synthesis, or antigen-production Project: M33 NOTE: Antiviral susceptibility results have been traditionally expressed as IC50 values.
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icterus serum with yellow color resulting from elevated bilirubin in the blood Project: C37 NOTE 1: Typically due to an increase of bile pigments in the blood, especially bilirubin, and often symptomatic of certain diseases, such as hepatitis; NOTE 2: A sample from a patient with icterus can produce erroneous test results due to either direct optical interference or chemical interference or both.
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icterus a yellow color resulting from an increased concentration of bilirubin Project: C56
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identification the process of establishing a claim to be a particular user Project: AUTO11 NOTE: Identification normally involves supplying a user identification, radio frequency identification badge, bar-coded badge without password, etc.
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identifier a single data element that is intended to indicate a person (patient), object derived from a person (patient), or the location of a person or specimen at the time of an event in health care Project: AUTO14 NOTE: Many professional medical societies, international standards organizations, and governments require a minimum of a two-identifier match in order to uniquely identify a patient or specimen in health care
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identity the extent to which two sequences (nucleotide or amino acid) are invariant Project: MM18
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idiospecificity a characteristic that describes the reactivity of an antiserum with a unique subset of a broad antigen class Project: DI01, I/LA23
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idiotype the characteristic of an antigen that makes it unique among all others of the same isotype Project: NRSCL08 NOTE: The term is usually applied to a monoclonal immunoglobulin, and the idiotypic characteristic has been shown to be located in the F(ab) combining site. (Cf. DI1)
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IEEE abbreviation for Institute of Electrical and Electronics Engineers, Inc. Project: AUTO01, AUTO07, AUTO02, AUTO03
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IEEE 1073 a family of standards for medical device communications that are optimized for the acute care setting Project: POCT01, POCT02 NOTE 1: Devices include patient monitors, ventilators, infusions pumps, pulse oximeters, etc.; standards include IEEE Standard 1073 and lower-layers IEEE Standard 1073.3.2; also referred to as “medical information bus”; NOTE 2: These are internationally harmonized as the ISO/IEEE 11073 set of standards.
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IFCC abbreviation for International Federation of Clinical Chemistry and Laboratory Medicine Project: AUTO01, AUTO02, AUTO03
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ignitable a substance that, under standard temperature and pressure, is capable of causing fire through friction, absorption of moisture, or other spontaneous chemical change and that, when ignited, will burn vigorously and persistently Project: GP05
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illuminate as used in I/LA24, to supply a measurand with a source of light for purposes of exciting fluorochrome molecules with which the measurand may be labeled Alternate Term: Illumination Project: I/LA24 NOTE 1: Fluorochrome molecules in the measurand are illuminated by incident light from the fluorometer; NOTE 2: These terms are often used interchangeably with the terms "excite/excitation." However, illumination is predetermined by instrument conditions alone, whereas excitation depends further on fluorochrome and environmental factors.
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image cytometer any of a group of instruments comprising fluorescence microscopes and microphotometers, image and scanning cytometers, and confocal microscopes that illuminate and collect optical signals from a microscopic field Project: I/LA24 NOTE: Image cytometers generally use microscope objectives (lenses with relatively high numerical aperture [N.A.] and magnification) to maximize illumination and detection efficiency.
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immature reticulocyte fraction a quantitative expression of the maturation state of the entire reticulocyte population in the peripheral blood Project: H44 NOTE 1: This has been expressed in terms of mean fluorescence intensity using thiazole orange on multiparameter flow cytometry instruments and as a fractional expression of the subpopulation of the reticulocytes having the highest fluorescence RNA intensity or RNA content; NOTE 2: Previously called reticulocyte maturation index.
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immature reticulocyte fraction a quantitative expression of the maturation state of the entire reticulocyte population in the peripheral blood Project: H44 NOTE 1: This has been expressed in terms of mean fluorescence intensity using thiazole orange on multiparameter flow cytometry instruments and as a fractional expression of the subpopulation of the reticulocytes having the highest fluorescence RNA intensity or RNA content; NOTE 2: Previously called Reticulocyte maturation index.
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immediate action act or deed performed without hesitation upon recognition or awareness of a nonconforming event Alternate Term: remedial action NOTE: The action should be documented.
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immediate container packaging that protects the contents from contamination and other effects of the external environment (ISO 18113-1)
Alternate Term: primary container Project: ISO 18113-1, ISO 18113-2, ISO 18113-3 EXAMPLES: Sealed vial, ampoule or bottle, foil pouch, sealed plastic bag (ISO 18113-1); NOTE: Does not include package liners (ISO 18113-1).
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immersion oil liquid medium, occupying the space between the object and microscope objective, used to optimize the resolution of the image being magnified Project: HS02, POCT10
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immune assay See immunoassay
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immune complex a complex formed of antigen and specific antibody molecules Project: NRSCL08, ILA29 NOTE: May also include complement components and other molecules as well.
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immune threshold the minimal level of specific antibody required for the protection of a person against an infectious agent Project: I/LA18
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immunoassay a diagnostic test that uses a specific antibody or antigen to detect the presence of an analyte Project: POCT15
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immunoassay any laboratory method for detecting a substance by using an antibody reactive with it (RHUD2CD) Project: I/LA34 NOTE: Immunoassays can be competitive or noncompetitive, solid or liquid phase, isotopic or nonisotopic, labeled antigen or immunometric (labeled antibody), single or dual site, homogeneous (no separation step), or heterogeneous (separation step). The majority of clinically used total immunoglobulin E and allergen-specific immunoglobulin E assays are noncompetitive heterogeneous immunometric assays.
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immunoassay a ligand-binding assay that uses a specific antigen or antibody capable of binding to the analyte Project: C45, NRSCL8
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immunoassay an analytical procedure in which antibodies are used to detect or quantify the corresponding antigen Alternate Term: immune assay Project: H59 NOTE: Immunoassays can be used to quantify D-dimer and some methods that may be employed are nonlabeled immunoassays/microparticle agglutination immunoassays, indicator-labeled immunoassays, and sandwich immunoassays.
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immunoassay any laboratory method for detecting a substance by using an antibody (pair) that is reactive with or binding to the measurand or substance of interest
Project: I/LA20, C63 NOTE: Immunoassays can be competitive or noncompetitive, solid or liquid phase, isotopic or nonisotopic, labeled antigen or immunometric (labeled antibody), single or dual site, homogeneous (no separation step), heterogeneous (separation step), or manual or automated with robotic autoanalyzers. The majority of clinically used total immunoglobulin E and allergen-specific immunoglobulin E assays are noncompetitive heterogeneous immunometric assays.
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immunoassay any laboratory method for detecting an analyte using an antibody reactive with it Project: I/LA28 NOTE: An immunoassay is a ligand-binding assay that uses a specific antigen or antibody capable of binding to the analyte.
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immunoassay a biochemical test that detects the presence of antigen or antibody in a biological specimen using the binding of an antibody to an antigen Project: M53
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immunocytochemical assay an immunoassay that detects an antigen present in a specimen that is contained within intact or histologically sectioned cells or tissues Alternate Term: immunohistochemical assay Project: MM04, H56, I/LA28 NOTE: Such an assay is also referred to as an immunohistochemical assay; the process that encompasses the preparation and examination of tissues stained in this way is variously referred to as immunocytochemistry, immunohistochemistry, immunohistology, or immunomicroscopy, among others.
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immunocytology localization of immunoreactive substances within cells of a cytological specimen that have been specifically labeled with an antibody Alternate Term: immunocytochemistry Project: H56
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immunodiffusion an immunological method for measuring antigens (eg, serum proteins) in which a small amount of serum (eg, 5 μL) is pipetted into a well cut into a porous agarose gel Project: I/LA20 NOTE 1: In the single immunodiffusion or Mancini assay, the gel contains antibody specific for the analyte of interest. As the analyte migrates through the gel by diffusion, it binds to antibody and forms a precipitin line at a point of optimal antigen-antibody binding or equivalence. In the double immunodiffusion assay, antigen and specific antibody are pipetted into separate wells in the same gel and they diffuse in all directions. A precipitin line forms at equivalence (the point of maximal antigen-antibody cross-linking). The shape and location of lines and diameter of precipitin rings provide information about the analyte’s quantity and quality; NOTE 2: Immunodiffusion is not used to measure immunoglobulin E antibodies in serum because of its inadequate lower limit of detection. Rather, it can be used by allergen manufacturers to qualify allergen extracts as part of a quality assurance program.It is also used in clinical immunology laboratories to evaluate patients suspected of having hypersensitivity pneumonitis who frequently have precipitins (precipitating antibodies) in their blood.
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immunogen any substance that elicits a cellular and/or humoral immune response and the production of antibody in a biological system Project: ILA18, I/LA23, I/LA34
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immunogenicity the ability of a biomolecule to elicit an antibody response Project: I/LA34
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immunoglobulin any of several classes of structurally related glycoproteins that function as antibodies or receptors and are found in plasma, other body fluids, and in the membranes of certain cells Project: DI01, MM05, I/LA28
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immunoglobulin a glycoprotein composed of two heavy and two light chains that functions as an antibody Project: I/LA34, NBS06, I/LA20 NOTE: Human immunoglobulins have been subdivided into different classes or isotypes (immunoglobulin M, immunoglobulin G1, immunoglobulin G2, immunoglobulin G3, immunoglobulin G4, immunoglobulin A1, immunoglobulin A2, immunoglobulin D, immunoglobulin E), each of which possesses a unique set of antigenic markers, physiochemical properties, and each of which produces a different pattern of effector functions (receptor binding, complement activation, opsonization). All antibodies are immunoglobulins, but it is not certain that all immunoglobulins possess antibody function.
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immunoglobulin class a classification of immunoglobins based on antigenic and structural differences of the heavy chain Alternate Term: immunoglobulin isotype Project: MM05, M36, NRSCL8 NOTE: There are five immunoglobulin classes: immunoglobulin G, immunoglobulin A, immunoglobulin M, immunoglobulin D, and immunoglobulin E.
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immunoglobulin E human immunoglobulin E is an immunoglobulin of the approximate molecular weight of 190 000, which exists normally in monomeric form and constitutes approximately 0.0005% of the total serum immunoglobulins Project: I/LA34, I/LA20 NOTE: It binds with high affinity to fragment crystallizable-epsilon receptor 1 mainly expressed on mast cells and basophils and fragment crystallizable-epsilon receptor 2 receptors on a number of other cells. Immunoglobulin E mediates the production and release of vasoactive mediators following the binding of allergen.
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immunoglobulin fragment a variable region of the IgG immunoglobulin molecule containing an antibody-combining site Alternate Term: antigen-binding fragment Project: NRSCL08 NOTE 1: Obtained by treating the molecule with the enzyme papain, specific fragments include: 1) F(ab) Fragment - the fragment consisting of a single antibody-combining site, embodied in an intact light chain and the F(d) fragment of one heavy chain, held together by means of a disulfide bond; 2) F(ab') Fragment - the fragment obtained after papain treatment and reduction, and consisting of an intact light chain and the F(d') fragment of one heavy chain, held together by means of a disulfide bond; 3) F(ab')2 Fragment - the fragment obtained after papain treatment without subsequent reduction and consisting of a dimer of two F(ab') fragments held together by two disulfide bonds; 4) F(c) Fragment - the crystallizable fragment containing the complement and rheumatoid factor-binding regions and consisting of two heavy chain fragments joined by two disulfide bonds; 5) F(d) Fragment - the fragment obtained after papain treatment and reduction, and consisting of that portion of the heavy chain joined to an intact light chain in the F(ab) fragment; 6) F(d') Fragment - the fragment obtained after papain treatment and reduction, and consisting of that portion of the heavy chain that is joined to an intact light chain in the F(ab') fragment.
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immunoglobulin isotype See immunoglobulin class Project: MM05
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immunoglobulin subclass a subdivision of immunoglobulin classes based on structural and antigenic differences in the H chain Project: NRSCL08 NOTE: For humans, there are four IgG subclasses: IgG1, IgG2, IgG3, and IgG4. For IgA, there are two subclasses: IgA1 and IgA2; IgM subclasses have been postulated; IgD and IgE subclasses are unknown.
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immunohematology the study of antigen-antibody reactions as they relate to transfusion medicine Project: I/LA33
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immunohistochemical of or relating to the application of histochemical and immunologic methods to chemical analysis of living cells and tissues Project: MM17
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immunohistochemical assay an immunoassay that detects an antigen present in a specimen that is contained within intact or histologically sectioned tissue Project: I/LA28 NOTE: Such an assay is also referred to as an “immunocytochemical assay”; the process that encompasses the preparation and examination of tissues stained in this way is variously referred to as “immunocytochemistry,” “immunohistochemistry,” “immunohistology,” or “immunomicroscopy,” among others.
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immunohistology localization of immunoreactive substances within cells or tissues of a histological specimen that have been specifically labeled with an antibody Alternate Term: immunohistochemistry Project: H56
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immunophenotyping characterization of cells by the identification of cell-surface or intracellular antigens, using antibody reagents that recognize specific cell-associated molecules Project: H42, H43, H52 NOTE: In H42, the cells that are immunophenotyped are lymphocytes and hematopoietic stem and progenitor cells; NOTE 2: In H52, the cells that are immunophenotyped are red blood cells and white blood cells.
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immunoprecipitation the separation of an antigen from a solution by the formation of a large insoluble complex with its specific antibody Project: NRSCL08
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immunoprecipitin analysis an immunoassay that relies on formation of a precipitate of antibody and antigen
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immunoreactive trypsinogen one of the secretory products of the pancreas, thus facilitating the use of its level in blood as a specific marker for pancreatic function Project: NBS05 NOTE: The acinar cells of the pancreas secrete two major forms of enzymatically inactive trypsinogen, which are subsequently activated to trypsin upon cleavage of a hexapeptide from the N-terminus.
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immunoreactivity See reactivity Project: I/LA28
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impedance the total electrical resistance measured between two electrodes Project: H58
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impedance aggregometry an in vitro platelet aggregation assay, primarily done in whole blood or diluted whole blood that measures the change in resistance between two electrodes caused by platelet clumping following activation of platelets by agonists Project: H58
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implementation putting into service, an instrument or method, by means of a definite plan or process Project: H57
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implementation the act of accomplishing some aim, executing some order, or carrying into effect Project: I/LA33
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implementation stage of the Test Life Phases Model; putting into service an instrument or test method by the end user for means of a definite plan or process Project: EP19, EP45
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implementation plan detailed listing of activities, costs, expected difficulties, and schedules that are required to achieve the objectives of the strategic plan Project: QMS13
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importer person/entity who imports a device into a country and furthers the marketing of a device from the original place of manufacture to the ultimate user ( ISO CD 18112-1) Project: ISO CD 18112-1
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importer person or legal entity who brings goods, or causes goods to be brought into a country from another country (ISO 18113-1)
Project: ISO 18113-1, ISO 18113-2, ISO 18113-3 NOTE 1: Importers are not permitted to repackage the goods or change their container, packaging or labelling in some jurisdictions, including the EU and USA (ISO 18113-1); NOTE 2: Adapted from US Code of Federal Regulations (CFR), Title 21, Part 803 — Medical Device Reporting Regulation 803.3 (m) (ISO 18113-1).
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imprecision (uncertainty of measurement) parameter, associated with the result of measurement, that characterizes the dispersion of the values that could reasonably be attributed to the measurand (the quantity intended to be measured) Project: POCT07
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imprecision dispersion of independent results of measurements obtained under specified conditions Project: EP10, EP14, I/LA23, C58, I/LA26, C48, H54, MM10, MM12, H57, C34, MM06, H59, GP34, MM19, MM01, C56, MM20, C40, MM22, H60, C62, C57, MM23, POCT13, POCT06, EP33, H48, C63 NOTE 1: For quantitative measurement procedures, it is expressed numerically as standard deviation or coefficient of variation; NOTE 2: It is expressed numerically as standard deviation or coefficient of variation; NOTE 3: It is expressed numerically as standard deviation or coefficient of analytical variation; NOTE 4: See precision.
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imprecision the random dispersion of a set of replicate measurements and/or values expressed quantitatively by a statistic, such as standard deviation or coefficient of variation Project: POCT14, H20, EP12, H26, EP23, ep21, EP27, EP09, EP26, EP05, C24, EP34, EP07, EP31 NOTE 1: It is defined in terms of repeatability and reproducibility; NOTE 2: The words “imprecision” and “precision” are often inappropriately interchanged; NOTE 3: It is expressed numerically as standard deviation or coefficient of variation; NOTE 4: See precision (of measurement); NOTE 5: For a qualitative, binary examination, imprecision can be characterized by the range of the interval from C5 to C95.
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imprecision the presence of random error, variability, or inconsistency Project: POCT04
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imprecision extent to which replicate measures disagree with one another, regardless of their relationship to a reference value Project: POCT05 NOTE: Imprecision is expressed numerically as standard deviation or coefficient of variation.
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imprecision for quantitative measurement procedures, dispersion of independent results of measurements obtained under specified conditions Project: NBS05 NOTE: Imprecision is expressed numerically as the standard deviation or the coefficient of variation (standard deviation divided by the mean measurement procedure result).
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imprecision for quantitative test methods, dispersion of results of replicate measurements obtained under specified conditions Project: EP19 NOTE: It is expressed numerically as the standard deviation or the coefficient of variation.
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Improvement Management Program an ongoing quality assessment and improvement process that establishes the most important monitoring targets to ensure the organization's ability to provide optimal customer satisfaction
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in cis two or more variants on the same parental gene Project: NBS05 NOTE: Two or more variants in the cystic fibrosis transmembrane conductance regulator gene on a single allele of chromosome 7
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in control characterization of a process when results from a control sample or a series of control samples are within the acceptable control range Project: POL1/2
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in silico an analysis performed on a computer or through computer simulation Project: M64, MM22, MM24
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in silico a biological experiment or simulation performed on a computer Project: C64
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in trans two variants on different parental genes Project: NBS05 NOTE 1: Variants in the cystic fibrosis transmembrane conductance regulator gene are on different alleles of chromosome 7; NOTE 2: Parental alleles can contain more than one variant.
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in vitro a Latin term, meaning “in glass,” used to describe diagnostic tests that analyze processes or quantities that originate inside the body (in vivo) based on samples of body fluids or tissues in glass (test tubes) or other controlled, artificial environments Project: POL1/2
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in vitro diagnostic (IVD) term used to describe those reagents, instruments, and systems intended for use in the diagnosis of disease or other conditions, including a determination of the state of health, in order to cure, mitigate, treat, or prevent disease or its sequelae. Such products are intended for use in the collection, preparation, and examination of specimens taken from the human body Project: NRSCL08
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in vitro diagnostic device a device intended by the manufacturer for in vitro examination of specimens derived from the human body solely or principally to provide information for diagnostic, monitoring, or compatibility purposes Project: MM09, MM17 NOTE: Like other medical devices, in vitro diagnostic devices are subject to regulatory approval by national and international authorities.
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in vitro diagnostic device in Europe, any medical device that is a reagent, reagent product, calibrator, control material, kit, instrument, apparatus, equipment, or system, whether used alone or in combination, intended by the manufacturer to be used in vitro for the examination of specimens, including blood and tissue donations, derived from the human body, solely or principally for the purpose of providing information (Directive 98/79/EC) Project: MM19 NOTE 1: In the United States, the US Food and Drug Administration defines in vitro diagnostic devices as those reagents, instruments, and systems intended for use in diagnosis of disease or other conditions, including a determination of the state of health, to cure, mitigate, treat, or prevent disease or its sequelae. Such products are intended for use in the collection, preparation, and examination of specimens taken from the human body; NOTE 2: In the United States, the US Food and Drug Administration regulates in vitro diagnostic devices, and these are subject to premarket and postmarket controls.
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in vitro diagnostic device term used to describe reagents, instruments, and systems intended for use in the diagnosis of disease or other conditions, including a determination of the state of health, to cure, mitigate, treat, or prevent disease or its sequelae. Such products are intended for use in the collection, preparation, and examination of specimens taken from the human body Project: MM22
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in vitro diagnostic instrument equipment or apparatus intended by a manufacturer to be used as an IVD medical device (ISO 18113-1) Alternate Term: IVD instrument Project: ISO 18113-1 NOTE: Adapted from EN 591:2001, definition 3.5 (ISO 18113-1).
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in vitro diagnostic instrument equipment or apparatus component of an in vitro diagnostic examination procedure that is used for detecting, measuring, controlling, or computing a quantity in a sample Project: AUTO11
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in vitro diagnostic medical device device, whether used alone or in combination, intended by the manufacturer for the in vitro examination of specimens derived from the human body solely or principally to provide information for diagnostic, monitoring, or compatibility purposes and including reagents, calibrators, control materials, specimen receptacles, software, and related instruments or apparatus or other articles (ISO 18113-1) Project: ISO 18113-1, ISO/DIS 14971
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in vitro diagnostic medical device a harmonized definition of medical device, including in vitro diagnostic medical device, has been proposed by the Global Harmonization Task Force, but has not yet been adopted by the participating countries;the European union, the United States, and Canada consider calibrators and control materials to be IVD medical devices and must be labelled as such;in Japan, IVD regulations do not apply to calibrators and control materials, unless they are part of a kit; accessories are IVD medical devices, according to EU definition, only when they are specifically intended for diagnostic use by their manufacturer Project: ISO/TR 18112
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in vitro diagnostic medical device a device, whether used alone or in combination, intended by the manufacturer for the in vitro examination of specimens derived from the human body solely to provide information for diagnostic, monitoring, or compatibility purposes and including reagents, calibrators, control materials, specimen receptacles, software, and related instruments or apparatus or other articles (GHTF/SG1/N045:2008) Project: GP16, ISO 18113-1, H26, EP23
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in vitro diagnostic medical device device for in vitro examination that includes, for example, reagents, calibrators, sample collection devices, control materials, and related instruments or apparatus, and that provides information that may be used for diagnostic, monitoring, or compatibility purposes Project: ISO CD 18113-1, ISO CD 18113-2, ISO CD 18113-3 NOTE: Taken from the Global Harmonization Task Force (GHTF) harmonized definition of medical device.
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in vitro diagnostic mobile application an application installed on a mobile device that allows an in vitro diagnostic system to be monitored and controlled Project: AUTO11
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in vitro diagnostic product chemical, biological, or immunological components, solutions, or preparations intended by the manufacturer to be used as an IVD medical device (adapted from EN375.2001, §3.9) Project: EP25 NOTE: For the purposes of EP25, “IVD product” also includes reagents, calibrators, controls, diluents
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in vitro diagnostic reagent chemical, biological, or immunological component of an in vitro diagnostic examination procedure that produces a signal by chemical or electrochemical reaction for the purpose of detecting or measuring a quantity in a sample (modified from ISO/DIS 17593)
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in vitro diagnostic reagent in vitro diagnostic medical device which is a reagent, calibrator, control material, or kit containing the components of an IVD assay (ISO/CD 18112-1) Project: ISO CD 18112-1 NOTE: For a harmonized definition of IVD medical device, see Global Harmonization Task Force (GHTF), Information Document Concerning the Definition of theTerm “Medical Device,” Proposed Final Document SG1/N029R13.
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in vitro diagnostic reagent chemical, biological, or immunological components, solutions, or preparations intended by the manufacturer to be used as an IVD medical device (ISO 18113-1)
Alternate Term: IVD reagent Project: ISO 18113-1 NOTE: Adapted from EN 375:2001, definition 3.9 (ISO 18113-1).
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in vitro diagnostic reagent chemical, biological, or immunological component, solution, or preparation intended by the manufacturer to be used as an IVD medical device (ISO 19001) Project: ISO 19001
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in vitro diagnostic software system a data management system for managing in vitro diagnostic testing in a health care delivery organization Project: AUTO11
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in vitro diagnostic system an in vitro diagnostic instrument or in vitro diagnostic software system Project: AUTO11
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in vitro diagnostic use diagnostic product cleared or approved by a national regulatory body for one or more specific intended uses with established analytical and clinical performance characteristics
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in vitro postantibiotic effect (PAE) the difference in the time for the number of exposed vs nonexposed bacteria to exhibit a 1-log10 increase in colony-forming units
Project: VET02 NOTE 1: It is measured after a complete removal of the antimicrobial agent to which the microorganism was exposed in vitro. The exposure concentrations relative to the minimal inhibitory concentration (MIC) should be indicated; NOTE 2: The in vitro PAE may vary as a function of the magnitude of the drug concentrations to which the bacteria were exposed relative to the MIC of that microorganism.
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in vitro stimulation a term used to indicate that an activating agent has been added to cells (often peripheral blood mononuclear cells) in culture Project: I/LA26 NOTE 1: The purpose is often to induce the expression of new cell surface markers (eg, activation markers) or other target molecules (eg, intracellular cytokines) on or in cells; NOTE 2: In vitro stimulation is a term also used to indicate that cells in culture have been induced to proliferation.
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in vivo postantibiotic effect (PAE) the difference in time for the number of bacteria in a tissue of treated vs untreated animals to exhibit a 1-log10 increase in colony-forming units after the unbound drug concentrations in serum or the infection site fall below the minimal inhibitory concentration of the microorganism Project: VET02
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inaccuracy numerical difference between a value and the true value Project: LA01, MM10, MM12, POCT04
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inaccuracy numerical difference between a measured value and the value of the measurand Project: C56, H60
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inactive hemoglobin See dyshemoglobin
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inactive leaf door section that is normally fixed in a closed position unless manually unlatched to open Project: QMS04
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inadequate blood volume a blood culture bottle containing less than 80% of the recommended minimum volume indicated on the bottle label Project: M47
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inborn errors of metabolism a phenotypically and genetically heterogeneous group of disorders caused by a defect in a metabolic pathway, leading to malfunctioning metabolism and/or the accumulation of toxic intermediate metabolites Project: NBS03 NOTE: Inborn errors of metabolism include amino acid breakdown disorders, fatty acid oxidation disorders, organic acid disorders, and enzymopathies.
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incidence an expression of the rate at which a certain event occurs, for example, the number of new cases of a specific disease occurring during a specific period Project: NRSCL08, GP45, H59 NOTE 1: The number of instances of illness or other outcomes commencing, or of persons falling ill, during a given period in a specified population; NOTE 2: More generally, the number of new events, eg, new cases of a disease in a defined population, within a specified period of time.
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incidence rate at which new cases of a disease occur in a population in a specified time Project: M53
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incident an individual occurrence or event
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incident command system a type of command structure specifically useful for management of emergency operations Project: GP36 NOTE 1: Incident command system implementation confers a standardized, scalable command and control structure that can include and coordinate diverse responders, such as public health authorities, medical workers, firefighters, and law enforcement personnel; NOTE 2: A useful, National Incident Management System–compliant resource for hospitals and health care is the Hospital Incident Command System, which adapts incident command systems specifically to a hospital environment. Hospital Incident Command System is the property of the California Emergency Medical Services Authority.
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incident light as used in I/LA24, the light supplied by a fluorometer to illuminate a measurand for purposes of exciting fluorochrome molecules with which the measurand may be labeled Project: I/LA24
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incidental finding as applied to next-generation sequencing, the results of a deliberate search for pathogenic or likely pathogenic alterations in genes that are not relevant to a diagnostic indication for which the sequencing test was ordered Project: MM26
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incision a cut into the skin, using a blade, causing blood to escape from the capillaries Project: GP42, NBS01
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incomplete agglutination any agglutination reaction that does not proceed to an apparent agglutination Project: DL01 NOTE: Caused by various conditions (eg, antibody without free valency to participate in lattice formation, a prozone phenomenon, hypoviscosity of the assay medium, excessive distance between particles due to high ionic strength of the reaction mixture, which precludes antibody bridging).
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incomplete anti-HIV antibody response the failure to produce the full complement of anti-HIV antibodies required to meet the criteria for HIV infection by supplemental serological testing Project: M53 NOTE 1: This result is also known as an indeterminate Western blot result; NOTE 2: This result is also known as an indeterminate result.
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inconclusive result as used in NBS06, a result from a newborn screening laboratory assay that cannot be classified as positive or negative Project: NBS06
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inconclusive screening result as used in NBS07, a result from a newborn screening laboratory assay that cannot be classified as positive or negative Project: NBS07
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inconsistent result results of two or more retests of the same newborn screening specimen that are sufficiently disparate from each other as to make the combined result uninterpretable Source: Newborn Screening Glossary
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incorrect result result that does not meet the requirements for its intended medical use Project: EP18, EP23 NOTE 1: In the case of quantitative test procedures, a result with a failure of measurement that exceeds a limit based on medical utility; NOTE 2: In the case of qualitative test procedures, a result that is contrary to a true value of the measurand.
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independent laboratory in GP36, a clinical laboratory that is not physically or directly associated with an acute care hospital; synonymous with “free standing” laboratory Project: GP36 NOTE: Independent laboratories do not inherit emergency preparedness assets that are available generally to many hospital laboratories, such as generator power, food services, security, medical expertise, behavioral health support, and facilities to house staff. They need to consider independently planning for these assets to meet their intended scopes of emergency operations.
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independent test a lupus anticoagulant test, screening or confirmatory, that is not paired with a test of the same principle Project: H60 NOTE: For example, the activated partial thromboplastin time is an independent screening test and the platelet neutralization procedure is an independent confirmatory test.
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indeterminate term sometimes used instead of “equivocal” or “gray zone,” separating the “target absent” and “target detected” zones Project: MM17 NOTE: In such assays, if the data generated by the assay fall within certain ranges, the data analysis may provide a result that is not definitive, such as neither “detected” nor “detected for a specific target” or neither heterozygous” nor “homozygous” for a specific mutation site.
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indeterminate not definitely or precisely determined or fixed; not leading to a definite end or result Project: H60
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indeterminate isolates a microorganism of undetermined clinical importance
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index fixed or movable part of a displaying device whose position with reference to the scale marks enables an indicated value to be determined (VIM93); EXAMPLES: a) pointer; b) luminous spot; c) liquid surface; d) recording pen
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index of circulating anticoagulant formula used to calculate a normalized ratio for a mixing test using either an independent or paired screening test; also referred to as the Rosner Index after the first author of the original publication Project: H60
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index of individuality the ratio of the combined within-subject biological variation and the measurement procedure imprecision (analytical imprecision) to the between-subject biological variation Project: EP33
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index swapping an incorrect association of a molecular bar code due to read errors Project: MM09
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indicating measuring instrument measuring instrument providing an output signal carrying information about the value of the quantity being measured (JCGM 200:2008) Project: ISO IEC Guide 99 EXAMPLES: Voltmeter, micrometer, thermometer, electronic balance (JCGM 200:2012); NOTE 1: An indicating measuring instrument may provide a record of its indication (JCGM 200:2012); NOTE 2: An output signal may be presented in visual or acoustic form. It may also be transmitted to one or more other devices (JCGM 200:2012).
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indication quantity value provided by a measuring instrument or a measuring system (JCGM 200:2012) Project: ISO IEC Guide 99, C51 NOTE 1: An indication may be presented in visual or acoustic form or may be transferred to another device. An indication is often given by the position of a pointer on the display for analog outputs, a displayed or printed number for digital outputs, a code pattern for code outputs, or an assigned quantity value for material measures (JCGM 200:2012); NOTE 2: An indication and a corresponding value of the quantity being measured are not necessarily values of quantities of the same kind (JCGM 200:2012); NOTE 3: An indication is a signal or reading from a measuring system. An indication is often given by the position of a pointer on the display for analog outputs, a displayed or printed number for digital outputs, a code pattern for code outputs, or an assigned quantity value for material measures.
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indication (of a measuring instrument) value of a quantity provided by a measuring instrument (VIM93) Project: ISO CD 18113-1, ISO CD 18113-2, ISO CD 18113-3 NOTE 1: The value read from the displaying device may be called the direct indication; it is multiplied by the instrument constant to give the indication; NOTE 2: The quantity may be the measurand, a measurement signal, or another quantity to be used in calculating the value of the measurand; NOTE 3: For a material measure, the indication is the value assigned to it.
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indication interval set of quantity values bounded by extreme possible indications (JCGM 200:2012) Project: ISO IEC Guide 99 NOTE 1: An indication interval is usually stated in terms of its smallest and greatest quantity values, for example, "99 V to 201 V" (JCGM 200:2012); NOTE 2: In some fields, the term is "range of indications" (JCGM 200:2012).
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indicator-labeled immunoassays a group of immunoassays in which the antibodies are labeled with an indicator (commonly enzyme, fluorescent, chemiluminescent, radioisotope). The positive reaction between labeled antibodies and/or antigens is detected by a system that measures some property of the indicator molecule. These are mostly heterogeneous assays that require the separation of the bound from the free fractions Project: H59 NOTE: Examples include enzyme-linked immunosorbent assays, chemiluminescence immunoassays, fluorescence immunoassays, and radioimmunoassays.
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indigenous originating in a particular region or environment; occurring naturally in an area
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indirect agglutination the agglutination technique in which antigen first is coated artificially onto particulate surfaces, either by physical absorption, or chemical or immunochemical linkage. These antigen-laden particles can then be used to detect the presence of the corresponding specific agglutinins in test material. Agglutination results by cross-linking of the antigen-bearing particles onto an extensive antigen-antibody lattice, ie, in detectable agglutination of the particles Alternate Term: passive agglutination Project: DL01
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indirect analysis systems that require dilution of the sample Project: C29 NOTE: These include some ion-selective, electrode-based systems, as well as flame emission photometry and atomic absorption.
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indirect antiglobulin technique an analytical method in which a particle (eg, erythrocyte or bacterium) is used to detect the presence of soluble incomplete antibodies by first causing it to react with test serum, with the subsequent addition of antiglobulin reagent resulting in complete agglutination Alternate Term: indirect Coomb’s test Project: DL01
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indirect antihuman globulin test a test in which antihuman globulin is used to detect antibody bound to red cell in vitro Project: I/LA33
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indirect contact transmission the transfer of an infectious agent from one patient to another through a contaminated intermediate object or individual Project: POCT04
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indirect cost a cost that cannot be identified directly with a particular activity, service, or product of the entity incurring the cost Project: GP45 NOTE: Indirect costs are usually apportioned among an entity’s services in proportion to each service’s share of direct costs.
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indirect cost an expense that is incurred in joint usage and therefore difficult to assign to or identify with a specific cost center or cost object Project: QMS20 NOTE 1: Indirect costs include costs such as administration, marketing, computing, maintenance, security, and supervision that are usually constant for a wide range of output; NOTE 2: Usually grouped with “fixed costs.”
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indirect FTH measurement procedures measurement procedures in which the free thyroid hormone concentration is inferred from measurements of the total hormone concentration and the free thyroid hormone fraction (eg, by equilibrium dialysis or symmetric dialysis) or a quantity reflecting the free thyroid hormone fraction (eg, fractional hormone uptake by a solid adsorbent such as solid phase antibody, ion-exchange resin, etc.) Project: C45
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indirect lighting lighting by lamps that direct the light upward towards the ceiling
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indirect methods nonexperimental verification methods that rely on analysis of typically large sets of sample data collected for other purposes than the verification study Project: EP45
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indirect susceptibility test a procedure based on inoculation of drug-containing media using organisms grown in pure culture Project: M24
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indistinguishable in bacterial strain typing, the results for two isolates are described as“indistinguishable” when both isolates give the same results; by definition, such isolates represent the same strain within that typing system Project: MM11, MM24 NOTE 1: The term “identical” may be used for precise typing systems, such as nucleotide sequencing, but is not appropriate for analog systems, such as those based on restriction fragment length polymorphisms, which have inherent limits of resolution; NOTE 2: See also different.
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individualized quality control plan a voluntary quality control option, effective in the United States as of 1 January 2016, that allows Clinical Laboratory Improvement Amendment–certified laboratories performing nonwaived testing to develop customized quality control plans based on risk management for use in their health care settings Project: MM22, M52
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inducible clindamycin resistance detection of the presence of a clindamycin resistance mechanism that is inducible (referred to as D-zone test when performed via disk diffusion) Project: M07
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inductance a magnetic field produced by the presence of an electric current Project: GP28
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infection the entry and multiplication of an infectious agent in the body of a person or animal with or without clinical symptoms Project: GP05 NOTE: Infection also means the entry of a toxin of an etiologic agent in the body of a person with or without clinical symptoms.
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infectious agent any microorganism that can invade body tissue and multiply, causing infection Project: POL1/2
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infectious agent a biological agent that can invade and multiply in body tissues, causing a condition that may be clinically unapparent or may result in the development of a disease Project: M29
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infectious substance a substance that contains a viable microorganism or its toxin, or a viral nucleic acid that is known, or is specified, to cause disease in animals or humans Project: H05
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infectious substance a viable microorganism or its toxin that is associated with human disease, capable of producing infection with or without disease, and is listed in the National Institutes of Health Guidelines for Research Involving Recombinant DNA Molecules, Appendix B, Classification of Human Etiologic Agents on the Basis of Hazard Project: GP05
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infectious substance a substance containing a viable microorganism, such as a bacterium, virus, rickettsia, parasite, or fungus, that is known or reasonably believed to cause disease in humans or animals Project: PRE04
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infectious substance a material known or reasonably expected to contain a pathogen that can cause disease in humans or animals and is listed in the National Institutes of Health (NIH) Guidelines for Research Involving Recombinant DNA Molecules, Appendix B, Classification of Human Etiologic Agents on the Basis of Hazard Project: QMS28
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infectious substance, Category A infectious substance in a form that, when exposure to it occurs, is capable of causing permanent disability or life-threatening or fatal disease in an otherwise healthy human or animal Alternate Term: Category A, infectious substance Project: M29 NOTE: Infectious substances, Category A are assigned the following the United Nations (UN) numbers and proper shipping names: 1) UN 2814, Infectious Substance, affecting humans; or 2) UN 2900, Infectious Substance, affecting animals only.
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infectious waste includes wastes containing, or potentially containing, pathogens of sufficient virulence and quantity so that exposure to the waste by a susceptible host could result in the development by that host of a communicable disease Project: GP05 NOTE: This waste type is also referred to as “medical waste,” “biohazardous waste,” “red bag waste,” and “regulated medical waste.”
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infectious waste waste containing or assumed to contain pathogens of sufficient virulence and quantity, so that exposure (eg, inhalation or percutaneous injury) to the waste by a susceptible host could result in a communicable disease Project: M29, POCT10, QMS28 NOTE 1: This waste type is also referred to as “medical waste,” “biohazardous waste,” “red bag waste,” and “regulated medical waste;”
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influence the phenomenon produced by an influence quantity Project: EP30 NOTE: The influence may result from lack of selectivity of the detection system, suppression of an indicator reaction, inhibition of the analyte (due to enzymes), or any other cause of specimen-dependent bias.
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influence quantity quantity that, in a direct measurement, does not affect the quantity that is actually measured, but affects the relation between the indication and themeasurement result (JCGM 200:2012) Project: ISO IEC Guide 99 EXAMPLE 1: Frequency in the direct measurement with an ammeter of the constant amplitude of an alternating current (JCGM 200:2012); EXAMPLE 2: Amount-of-substance concentration of bilirubin in a direct measurement of haemoglobin amount-of-substance concentration in human blood plasma (JCGM 200:2012); EXAMPLE 3: Temperature of a micrometer used for measuring the length of a rod, but not the temperature of the rod itself, which can enter into the definition of the measurand (JCGM 200:2012); EXAMPLE 4: Background pressure in the ion source of a mass spectrometer during a measurement of amount-of-substance fraction (JCGM 200:2012); NOTE 1: An indirect measurement involves a combination of direct measurements, each of which may be affected by influence quantities (JCGM 200:2012); NOTE 2: In the GUM, the concept ‘influence quantity’ is defined as in the second edition of the VIM, covering not only the quantities affecting the measuring system, as in the definition above, but also those quantities that affect the quantities actually measured. Also, in the GUM, this concept is not restricted to direct measurements (JCGM 200:2012).
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influence quantity quantity that is not the measurand but that affects the result of the measurement (modified from JCGM 200:2012) Project: EP32
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information data shaped into a form that is meaningful and useful to support decision-making, coordination, and control in an organization Project: QMS26, QMS22, QMS12, QMS01 Source: Quality Glossary
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information access service advertises capabilities of Infrared Data Association devices Alternate Term: IrLMP-IAS Project: POCT01 NOTE: Also termed IrLMP-IAS.
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information security practice of protecting information (both paper and electronic) and information systems against unauthorized access or modification, whether the information is in storage, processing, or transit, and against denial of service to authorized users Project: QMS22 NOTE 1: Information security includes those measures necessary to detect, document, and counter such threats; NOTE 2: Information security is composed of computer security and communications security, including personnel awareness and education.
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information supplied by the manufacturer all printed, written, graphic, or other information annexed to, or accompanying an in vitro diagnostic reagent (modified from ISO 19001) Alternate Term: labelling Project: ISO 19001, M50
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information supplied by the manufacturer written, printed, or graphic matter affixed to an IVD medical device or any of its containers or wrappers or provided for use with an IVD medical device, related to identification and use, and giving a technical description, of the IVD medical device, but excluding shipping documents (ISO 18113-1) Alternate Term: labelling Project: ISO 18113-1, ISO 18113-2, ISO 18113-3 NOTE 1: In IEC standards, documents provided with a medical device and containing important information for the responsible organization or operator, particularly regarding safety, are called “accompanying documents” (ISO 18113-1); NOTE 2: Catalogues and material safety data sheets are not considered labelling of IVD medical devices (ISO 18113-1); EXAMPLES: Labels, instructions for use (ISO 18113-1).
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information supplied by the manufacturer information related to identification, description, safety, and use of an in vitro diagnostic medical device; including, for example, labels, instructions for use, and promotional materials, but excluding shipping documents, safety data sheets, and catalogues (ISO TR 18112-1) Alternate Term: labelling Project: ISO CD 18112-1, M50
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information supplied by the manufacturer written, printed, or graphic matter affixed to an IVD medical device or any of its containers or wrappers or provided for use with an IVD medical device, related to identification, technical description, and use of the IVD medical device, but excluding shipping documents (ISO 19001) Alternate Term: labelling Project: ISO 19001
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information supplied by the manufacturer (labeling) printed, written, graphic, or other information affixed to, or accompanying an in vitro diagnostic medical device, including instructions for use and labels on any of its packaging (modified from ISO 18113-1) Alternate Term: labeling Project: ISO 15197
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information supplied by the manufacturer with the medical device all written, printed, or graphic matter on a medical device or any of its containers or wrappers, or accompanying a medical device, relating to the identification, technical description, and use of the medical device, but excluding shipping documentation and promotional material (ISO 15198) Project: ISO 15198, ISO CD 17593, ISO 15197, ISO/DIS 17593 NOTE: In some countries, information supplied by the manufacturer is called "labelling" (ISO 15198).
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information technology support customer support personnel familiar with and responsible for the maintenance of computer hardware, operating system software, commercial off-the-shelf software components, and networking environment Project: AUTO11
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informed consent the process by which a person voluntarily confirms the willingness to participate in a particular medical procedure after having been informed of all aspects of the procedure that are relevant to the decision to participate Project: MM19, MM20, POCT12, MM22 NOTE: Informed consent is documented by means of a written, signed, and dated informed consent form.
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infrared the transmission of data using light in the lower energy, longer wavelength range by Infrared Data Association devices Project: POCT02
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infrared the physical layer typically used by infrared data association devices Project: POCT01
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Infrared Data Association an organization that creates and promotes interoperable, low-cost infrared data interconnection standards (www.irda.org) Project: POCT01 NOTE: “Infrared Data Association” also refers to the protocol stack authored by that group.
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inhibition reduction in amplification or detection of products causing false-positive or false-negative results in a test system due to components within a clinical specimen or exogenous substances introduced during specimen collection or processing Project: M55
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inhibition components within the clinical specimen or exogenous substances introduced during specimen collection/processing that reduce amplification or detection Project: MM03, MM22, MM24
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inhibitor in biochemistry, any substance or agent that inhibits an enzymatic reaction, especially important for polymerase chain reaction–based assays Project: MM13
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in-house developed assay See laboratory-developed assay Project: I/LA28
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initial test a test that is used to screen for HIV-1 or HIV-1 and HIV-2 infection Project: M53
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inner filter effect an apparent decrease in emission quantum yield and/or distortion of bandshape as a result of reabsorption of emitted radiation, or absorption of incident radiation by a species other than the intended primary absorber (IUPAC Compendium of Chemical Technology, 2nd ed: 1997) Project: I/LA24
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inoculation implanting microorganisms or other substances into a culture medium to allow them to grow Project: POL1/2
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inoculum number of bacteria in a suspension, calculated with respect to the final volume (ISO 20776-1) Project: ISO 20776-1 NOTE 1: The inoculum is expressed as colony-forming units per milliliter (CFU/mL) (ISO 20776-1); NOTE 2: A suspension of microorganisms used to inoculate a microbial identification system or antimicrobial susceptibility testing system.
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inoculum number of microorganisms in a suspension, calculated with respect to the final volume (modified from ISO 20776-1) Project: M52 NOTE 1: A suspension of microorganisms used to inoculate a microbial identification system or antimicrobial susceptibility testing system; NOTE 2: The inoculum is expressed as colony-forming units per milliliter (CFU/mL) (modified from ISO 20776-1).
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inoculum microorganisms dispensed or mixed in a culture medium or microbial identification system prior to testing Project: M50
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inoculum a substance, or portion of a specimen, implanted in a culture medium Project: POL1/2
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inoculum effect change in MIC related to change in inoculum (ISO 20776-1) Project: ISO 20776-1
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inpatient patient who comes to a hospital or other health care facility for diagnosis or treatment that requires an overnight stay (Dorland's Illustrated Medical Dictionary. 33rd ed. Elsevier, Inc.; 2019) Project: PRE02
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input quantity See input quantity in a measurement model Alternate Term: input quantity in a measurement model Project: C51
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input quantity in a measurement model quantity that must be measured, or a quantity, the value of which can be otherwise obtained, in order to calculate a measured quantity value of ameasurand (JCGM 200:2008) Alternate Term: input quantity Project: ISO IEC Guide 99, C51 EXAMPLE 1: When the length of a steel rod at a specified temperature is the measurand, the actual temperature, the length at that actual temperature, and the linear thermal expansion coefficient of the rod are input quantities in a measurement model (JCGM 200:2012); NOTE 1: An input quantity in a measurement model is often an output quantity of a measuring system (JCGM 200:2012); NOTE 2: Indications, corrections, and influence quantities can be input quantities in a measurement model (JCGM 200:2012); EXAMPLE 2: The temperature, cofactor concentrations, duration of incubation, and change in absorbance due to the change in product concentration can be input quantities in a measurement model for catalytic concentration of an enzyme in blood plasma (JCGM 200:2008 § 2.50).
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input station part of an automation line at which specimens are placed to begin transport on line
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input variable the value, usually represented by x, that is used as a reference (independent variable) and against which the output variable is compared
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input variable the value {and/or random variable} that is used as a reference (independent variable) and against which the output variable (dependent) is compared Project: NRSCL08 NOTE: The input variable is represented by X; the subscript may be used to represent an individual observation and its values are plotted along the x-axis (abscissa).
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input variable the given value that is used as a reference (independent variable) and against which the output variable is compared NOTE: The input variable is represented by X with individual values of X noted by xi (i represents an individual observation); its value is plotted along the X-axis (abscissa).
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in-range result test result that is within the expected range of testing results Project: NBS06, NBS01, NBS13, NBS09, NBS03, NBS05, NBS02, NBS10 Source: Newborn Screening Glossary NOTE: See expected range.
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insertion addition of one or more nucleotides into nucleic acid sequence Project: MM18
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insertion the addition of one or more nucleotide base pairs into a DNA sequence. Insertion variants can occur in microsatellite regions due to the DNA polymerase slipping Project: MM19 NOTE: Insertions can be anywhere in size from one base pair incorrectly inserted into a DNA sequence to a section of one chromosome inserted into another.
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insertion and/or deletion a variant characterized by an insertion, a deletion, or a combination of a deletion and an insertion at the same site Project: MM09 NOTE 1: A sequence variant arising from both an insertion and a deletion; NOTE 2: Sometimes used in a general sense to describe the category of variants that includes both insertions and deletions.
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inside liquid storage room one-hour fire-rated room suitable for storage of flammable liquids located inside a building Project: QMS04
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installation qualification confirmation that each component of the automated system has been installed according to the vendor’s specifications and that the functional tests have been performed and documented with expected results Project: I/LA33
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installation qualification a set of formal checks and records that confirms the equipment or process and its components, including any integral hardware or software, were supplied as ordered and properly installed in the laboratory or other environment Project: QMS18, MM17, QMS01, H62 Source: Quality Glossary NOTE: Installation qualification can be performed by the manufacturer’s technical service engineer.
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instance level describes the specific laboratory equipment that was used by an identifier such as an in vitro diagnostic instrument serial number or test reagent kit lot number (eg, instrument #1 of the three available for use in the laboratory) Project: AUTO17
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Institute of Electrical and Electronics Engineers an international, American National Standards Institute–accredited standards development organization dedicated to the advancement of electrical and information technologies Alternate Term: IEEE Project: POCT02, POCT01 NOTE 1: Among its many roles, the Institute of Electrical and Electronics Engineers sets standards for the electronics industry such as IEEE Standard 1073 for Medical Device Communications and IEEE Standard 802.3, which forms much of the foundation for the Internet (www.ieee.org); NOTE 2: Among its many roles, the Institute of Electrical and Electronics Engineers sets standards for the electronics industry such as IEEE Standard 1073 for Medical Device Communications and IEEE Standard 802.3, which forms much of the lower-layers foundation for the Internet (www.ieee.org).
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institutional review board in the United States, the standing committee in a medical school, hospital, or other health care facility that is charged with ensuring the safety and well-being of human subjects involved in research Project: GP45 NOTE 1: The institutional review board is responsible for ethical review of research proposals; NOTE 2: Many synonyms are used in other countries (eg, Ethical Review Committee, Research Ethics Board); NOTE 3: All research, including epidemiological research, that involves human subjects must be approved by an institutional review board or equivalent body.
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instructions for use information supplied by the manufacturer with an in vitro diagnostic medical device concerning the safe and proper use of the reagent or the safe and correct operation, maintenance, and basic troubleshooting of the instrument (ISO 15198) Alternate Term: directions for use Project: ISO 15197, ISO 17593, ISO 15198, I/LA33, EP23 NOTE 1: Instructions for use for in vitro diagnostic reagents for self-testing are described in EN 376 and ISO/DIS 18113-4; NOTE 2: Instructions for use for in vitro diagnostic instruments for self-testing are described in EN 592 and ISO/DIS 18113-4; NOTE 3: Instructions for use may take the form of package insert sheets and/or user manuals.
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instructions for use information supplied by the manufacturer with a test system concerning the safe and proper use of the reagent or the safe and correct operation, maintenance, and basic troubleshooting of the test system (modified from ISO 15198) Project: EP18
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instructions for use (product insert) information supplied by the manufacturer with an in vitro diagnostic medical device concerning the safe and proper use of the reagent or the safe and correct operation, maintenance, quality control guidelines (streamlined and regular), and basic troubleshooting of the instrument (modified from ISO 15198) Alternate Term: product insert Project: M50 NOTE: Modification from these instructions constitutes a modified microbial identification system.
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instructions for use information supplied by the manufacturer to enable the safe and proper use of an in vitro diagnostic medical device (ISO 18113-1) Alternate Term: package insert Project: M52 NOTE 1: Includes the directions supplied by the manufacturer for the use, maintenance, troubleshooting, and disposal of an in vitro diagnostic medical device, as well as warnings and precautions (ISO 18113-1); NOTE 2: Includes information concerning the safe and proper use of the reagent or the safe and correct operation, maintenance, quality control guidelines (streamlined and regular), and basic troubleshooting of the instrument; NOTE 3: Modification from these instructions constitutes a modified system or off-label usage.
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instructions for use information supplied by the manufacturer to enable the safe and proper use of an IVD medical device (ISO 18113-1)
Project: ISO 18113-1 NOTE: Includes the directions supplied by the manufacturer for the use, maintenance, troubleshooting and disposal of an IVD medical device, as well as warnings and precautions (ISO 18113-1).
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instructions for use information required by the user for the safe and effective use of a medical device Alternate Term: directions for use Project: ISO CD 18112-1 NOTE: Instructions for use for in vitro diagnostic medical devices may take the form of package insert sheets, user manuals, and/or other media.
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instructions for use information required by the user for the safe and proper use, maintenance, troubleshooting and disposal of an IVD medical device (EN 375) Alternate Term: directions for use NOTE: Instructions for use for in vitro diagnostic medical devices may take the form of insert leaflets, user manuals, and/or other media.
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instructions for use general and technical information provided by the manufacturer to inform the user of a device’s intended purpose and proper use and of any contraindications, warnings, or precautions to be taken Project: POCT18 NOTE: Labeling requirements are different for in vitro diagnostic devices receiving an emergency use authorization vs 510(k) products. As such, instead of a package insert, which accompanies 510(k) products, emergency use authorization products have instructions for use.
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instrument an analytical unit that performs chemical or physical assays on samples (eg, chemistry analyzer, hematology analyzer) Project: AUTO03
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instrument an analytical unit that uses samples to perform chemical or physical assays (eg, chemistry analyzer, hematology analyzer) Project: AUTO01, AUTO02, POCT04
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instrument a device that will give analytical answers as a result of electrical or mechanical measurements on an element, compound, solution, etc. Project: AUTO01, M29
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instrument constant coefficient by which the direct indication of a measuring instrument must be multiplied to give the indicated value of the measurand or of a quantity to be used to calculate the value of the measurand (VIM93) NOTE 1: Multirange measuring instruments with a single display have several instrument constants that correspond, for example, to different positions of a selector mechanism; NOTE 2: Where the instrument constant is the number one, it is generally not shown on the instrument.
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instrument flags alerts (or flags) of any kind from an analyzer; the manufacturer has deemed that these items are or may be of interest to the user Project: AUTO15
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instrument output the result of a measurement by an instrument NOTE: The instrument output need not be the final analytical result.
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instrument verification a documented procedure for ensuring that point-of-care blood glucose meter instruments are performing according to the manufacturer’s established criteria Project: POCT12
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instrumental bias average of replicate indications minus a reference quantity value (JCGM 200:2012) Project: ISO IEC Guide 99
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instrumental drift continuous or incremental change over time in indication, due to changes in metrological properties of a measuring instrument (JCGM 200:2008) Project: ISO IEC Guide 99 NOTE: Instrumental drift is related neither to a change in a quantity being measured nor to a change of any recognized influence quantity (JCGM 200:2012).
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instrumental measurement uncertainty component of measurement uncertainty arising from a measuring instrument or measuring system in use (JCGM 200:2012) Project: ISO IEC Guide 99 NOTE 1: Instrumental measurement uncertainty is obtained through calibration of a measuring instrument or measuring system, except for a primary measurement standard for which other means are used (JCGM 200:2012); NOTE 2: Instrumental uncertainty is used in a Type B evaluation of measurement uncertainty (JCGM 200:2012); NOTE 3: Information relevant to instrumental measurement uncertainty may be given in the instrument specifications (JCGM 200:2012).
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instrument-specific ISI See thromboplastin-specific ISI Project: H54
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integer mass the mass expressed as a whole number Project: C50 NOTE: In contrast, the exact mass value has a decimal component determined by the precision of the mass measurement.
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integral consisting of one piece, such as an integral baseboard with vinyl flooring, or an integral sink with countertop Project: QMS04
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integral biomarker biomarker that is used for clinical decision-making within clinical trials and that is essential for the performance of the trial Project: MM23 NOTE: Integral biomarkers can include prognostic, predictive, pharmacogenomic, or occasionally pharmacodynamic markers and are used to determine patient eligibility for a trial, a patient’s assignment to therapy, dose selection, or patient stratification within a trial.
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integrated biomarker biomarker that is evaluated for all patients within a trial or for a statistically predefined subset but that is not used for medical decision-making Project: MM23 NOTE: Integrated biomarkers are intended for clinical research or development of a marker and its corresponding assay for use in a subsequent trial.
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integrated continuous glucose monitor (iCGM) a continuous glucose monitoring system intended to reliably and securely transmit glucose measurement data to digitally connected devices, including automated insulin dosing systems, for the purpose of managing a disease or condition related to glycemic control Project: POCT05
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integrated functional control control material that is inherent in a reagent component of a measuring system, intended by the manufacturer to verify the performance of the measuring system (ISO 17593) Project: ISO 17593 NOTE: The integrated functional control is run concurrently with a patient measurement, includes a reactive component, and provides a functional check of the procedure. The integrated control results must be within a predefined measurement interval for the measured value to be displayed (ISO 17593).
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integrated test system a lupus anticoagulant test system that simultaneously incorporates a screening, confirmatory, and mixing test (no step can be performed independently), eg, the hexagonal phase phospholipid neutralization test Project: H60
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integrating measuring instrument measuring instrument that determines the value of a measurand by integrating a quantity with respect to another quantity (VIM93)
EXAMPLE electrical energy meter. (VIM93)
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integrity See data integrity and system integrity (RFC 2828) Project: AUTO09
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integrity (molecular, RNA) a measure of functionality, typically of an RNA molecule, by assessing intactness (full-length), 3ʹ poly(A) and 5ʹ cap structures, as well as purity Project: MM13
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integrity condition of maintaining the specimen’s in vivo qualitative and quantitative characteristics with respect to its measurands Project: PRE04 NOTE: This entails having the same in vivo qualitative and quantitative characteristics throughout the path of workflow
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intended use use for which a product, process, or service is intended, according to the specifications, instructions, and information provided by the manufacturer (ISO 14971) Alternate Term: intended purpose Project: POCT18, ISO 14971, EP18, EP14, EP19, POCT17 NOTE 1: The clinical use for which the measurement procedure was originally designed; NOTE 2: The concept includes definition of the measurand, the target condition, and the clinical use of the measurement procedure, which may include screening, diagnosis, prognosis, and/or monitoring of patients; NOTE 3: The intended use of an in vitro diagnostic device is determined by the manufacturer during the device development stage. Typically, the intended use of an in vitro diagnostic device is to identify the disease or condition the device diagnoses, treats, prevents, cures, or mitigates. A description of the patient population for which the device is intended is also included, as well as information on the type of test (eg, quantitative or qualitative), underlying technology (eg, enzymatic, immunochromatographic, nucleic acid based), and the type of specimen that may be used (eg, serum, plasma, nasal swab). Sometimes, the intended use of the device includes the type(s) of setting (eg, over the counter, prescription, point of care) for which the device may be used. The manufacturer performs clinical and analytical validation studies to generate data to support the intended-use claims.
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intended use objective intent of an in vitro diagnostic manufacturer regarding the use of a product, process, or service as reflected in the specifications, instructions, and information supplied by the in vitro diagnostic manufacturer (ISO 18113-1)
Alternate Term: intended purpose Project: ISO 18113-1, ISO 18113-2, ISO 18113-3, POCT09 NOTE 1: Intended use statements for in vitro diagnostic labelling can include two components: a description of the functionality of the in vitro diagnostic medical device (eg, an immunochemical measurement procedure for the detection of analyte “x” in serum or plasma), and a statement of the intended medical use of the examination results (ISO 18113-1); NOTE 2: This is the definition adopted by the GHTF in Global Harmonization Task Force (GHTF), Labelling for Medical Devices, Final DocumentGHTF/SG1/N43:2005, 3 June 2005 (ISO 18113-1).
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intended use objective intent of the manufacturer or other legal entity, or person, under whose name a device is placed on the market, in respect of the application and performance of the device, as indicated in the information supplied by the manufacturer Alternate Term: intended purpose Project: ISO/CD 18112-1
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intended use the clinical use for which the measurement procedure was originally designed NOTE: The concept includes definition of the measurand, the target condition, and the clinical use of the measurement procedure, which may include screening, diagnosis, prognosis, and/or monitoring of patients.
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intention tremor a dyskinetic disorder consisting of wide tremor during voluntary movements. The tremor worsens when a person is moving. It is the result of dysfunction of the cerebellum and is therefore part of the characteristic symptoms of cerebellar ataxia
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intention-to-treat analysis a strategy for analyzing data in which all participants are included in the group to which they were assigned, whether or not they completed the intervention given to the group Project: GP45 NOTE: Intention-to-treat analysis prevents bias caused by the loss of participants, which may disrupt the baseline equivalence established by random assignment and which may reflect nonadherence to the protocol.
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intercept the point where a function intersects an axis Alternate Term: Y intercept Project: NRSCL08 NOTE: The y-intercept is the value of the y-variable when the x-variable has a value of zero.
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intercept the value of a variable, when the value for the other variables is zero Project: NRSCL08 NOTE 1: The y-intercept is the value of the y-variable when the x-variable has a value of zero; NOTE 2: The x-intercept is the value of the x-variable when the y-variable has a value of zero; NOTE 3: For example, a line y = mx + b has two intercepts: at the y-axis, the y-intercept is the point (0,b) and at the x-axis, the x-intercept is the point (- b/m, 0). Often the intercept is referred to as the value of the variable whose axis is intercepted, e.g., b for the y-intercept; NOTE 4: There are as many potential intercepts as the function has variables; NOTE 5: Often the term "intercept" is used to mean "y-intercept." To avoid ambiguity, refer to the variable for which a value is sought when all other variables are set to zero.
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intercept 1) the point where a function intersects an axis; 2) the value of a variable, when the value for the other variables is zero Alternate Term: Y intercept NOTE: The y-intercept is the value of the y-variable when the x-variable has a value of zero.
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interface 1) a shared boundary between two functional units, defined by functional characteristics, common physical interconnection characteristics, signal characteristics, and other characteristics, as appropriate; the concept involves the specification of the connection of two devices having different functions; 2) a point of communication between two or more processes, persons, or other physical entities; 3) a peripheral device that permits two or more devices to communicate (ISO/IEC International Standard 812) Project: AUTO08, I/LA33
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interface a connection between computer systems or devices to allow communication and exchange of data Project: POCT02
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interference artifactual increase or decrease in apparent concentration or intensity of an analyte due to the presence of a substance that reacts nonspecifically with the measurement system Project: H62 NOTE 1: The effect may result from nonspecificity of the detection system, suppression of an indicator reaction, inhibition of analyte (enzymes), or any other cause of specimen-dependent bias; NOTE 2: In laboratory medicine and clinical chemistry, a cause of clinically significant bias in the measured analyte concentration due to the effect of another component or property of the sample.
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interference (analytical) artifactual increase or decrease in apparent concentration or intensity of an analyte (or measurand) due to the presence of a substance that reacts nonspecifically with either the detecting reagent or the signal itself Project: EP11, ILA18, LA01, MM10, H20, H26, MM24, EP39
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interference in clinical chemistry, a cause of medically significant difference in the measurand test result due to the effect of another component or property of the sample Project: EP07, POCT05 NOTE: Interference may result from nonselectivity of the detection system, suppression of an indicator reaction, inhibition of the measurand (enzymes), or some other cause of specimen-dependent difference.
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interference (analytical) the effect of substances in the sample that make the test give wrong results Project: POCT08, POCT15 NOTE 1: Interferences can make a test turn positive when the material to be measured (the “target”) is absent, keep it from turning positive even though the target is present, or make the measured amount of the target significantly different from the real value; NOTE 2: Interferences may be identified or unidentified substances. Some are well known, such as soap added to urine for drug of abuse testing to keep it from turning positive or EDTA anticoagulant from a blood collection tube causing extremely low calcium values. Others are sporadic and difficult to characterize.
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interference in laboratory medicine and clinical chemistry, a cause of clinically significant bias in the measured analyte concentration due to the effect of another component or property of the sample Project: C56
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interference claim statement describing the effect that a substance may have on a measurement procedure Project: EP07, C56 NOTE: It is typically included in the product labeling under “Limitations of the Method.”
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interference criteria difference allowed for interference effect on the measurement that will not alter a medical caregiver’s diagnosis, treatment, or management of a patient Project: C56, EP07
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interference screen in the evaluation of an analytical system, a series of tests performed with high concentrations of commonly occurring substances to identify those that are likely to cause interference Project: EP07
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interference sensitivity susceptibility of a measurement procedure to error caused by interference from other components or properties of the sample Project: C56
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interferent quantity that, in a direct measurement, does not affect the quantity that is actually measured, but affects the relation between the indication and the measurement result (modified from JCGM 200:2012) Project: I/LA28, C56, EP07 NOTE 1: “Interferent” is defined in the same way “influence quantity” is defined by international metrology vocabulary; NOTE 2: A substance that causes the measurement to be inaccurate.
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interferent substance or matrix that alters the expected result of a measurement procedure by cross-reactivity or other means Project: C52, C63
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interferent a component of the reagent that has the potential to cause a bias in the measured analyte concentration Project: EP47
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interfering substance a component of the sample, other than the analyte, that causes a bias in the measured analyte concentration Alternate Term: interferent Project: C56
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interfering substances endogenous (eg, blood components, acidic polysaccharides) or exogenous (eg, talc, anticoagulant) substances in patient specimens that can cause incorrect (false-positive or false-negative) results in a test system Project: I/LA33, M55, MM22, MM09, MM03, MM17, MM24 NOTE: “Interfering substance” can also be used to refer to nontarget organisms or sequences that may cause false-positive results.
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interim analysis any data analysis that is performed during the clinical evaluation and before the evaluation is completed Project: I/LA21 NOTE 1: Analyses performed at intervals throughout the evaluation provide the sponsor with estimates of the new assay’s performance; NOTE 2: These estimates are of limited validity due to insufficient sample size.
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interinstrument bias the difference observed by comparing two specified instruments’ or laboratories’ methods under specified conditions of analysis, concentration range, method, etc Alternate Term: intermethod or interlaboratory bias Project: NRSCL08
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interlaboratory comparisons organization, performance, and evaluation of measurements or tests on the same or similar items by two or more laboratories in accordance with predetermined conditions (ISO Guide 43-1)
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intermediate (I) for breakpoints, bacterial strain inhibited in vitro by a concentration of an antimicrobial agent that is associated with uncertain therapeutic effect (ISO 20776-1) Project: ISO 20776-1, ISO 20776-2 NOTE 1: Bacterial strains are categorized as intermediate by applying the appropriate breakpoints in a defined phenotypic test system (ISO 20776-1); NOTE 2: This class of susceptibility implies that an infection due to the isolate can be appropriately treated in body sites where the drugs are physiologically concentrated or when a high dosage of drug can be used (ISO 20776-1); NOTE 3: This class also indicates a "buffer zone," to prevent small, uncontrolled, technical factors from causing major discrepancies in interpretations (ISO 20776-1); NOTE 4: These breakpoints can be altered due to changes in circumstances (e.g., changes in commonly used drug dosages, emergence of new resistance mechanisms) (ISO 20776-1).
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intermediate antimicrobial susceptibility test interpretive category a category that includes isolates with antimicrobial agent MICs that approach usually attainable blood and tissue levels and for which response rates may be lower than for susceptible isolates and/or available data do not permit them to be clearly categorized as either “susceptible” or “resistant” NOTE: This category also includes a buffer zone, which should prevent small, uncontrolled, technical factors from causing major discrepancies in interpretations.
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intermediate antimicrobial susceptibility test interpretive category the “intermediate” category includes isolates with antimicrobial agent MICs that approach usually attainable blood and tissue levels and for which response rates may be lower than for susceptible isolates and/or available data do not permit them to be clearly categorized as either “susceptible” or “resistant.” This category also includes a buffer zone, which should prevent small, uncontrolled, technical factors from causing major discrepancies in interpretations
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intermediate antimicrobial susceptibility test interpretive category a category that includes isolates with antimicrobial agent MICs that approach usually attainable blood and tissue levels and for which response rates may be lower than for susceptible isolates. The intermediate category implies clinical efficacy in body sites where the drugs are physiologically concentrated (eg, quinolones and β-lactams in urine) or when a higher than normal dosage of a drug can be used (eg, β-lactams). This category also includes a buffer zone, which should prevent small, uncontrolled, technical factors from causing major discrepancies in interpretations, especially for drugs with narrow pharmacotoxicity margins
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intermediate antimicrobial susceptibility test interpretive category for minimal inhibitory concentration, an interpretive category that implies that an infection due to the isolate may be appropriately treated in body sites where the drugs are physiologically concentrated or when a high dosage of drug can be used; also indicates a "buffer zone" that should prevent small, uncontrolled, technical factors from causing major discrepancies in interpretations
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intermediate antimicrobial susceptibility test interpretive category a category that implies that an infection due to the isolate may be successfully treated in body sites where the drugs are physiologically concentrated or when a higher approved dosage of drug can be used; also indicates a “buffer zone” that should prevent small, uncontrolled, technical factors from causing major discrepancies in interpretations
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intermediate antimicrobial susceptibility test interpretive category a category that implies that an infection due to the isolate may be successfully treated in body sites where the drugs are physiologically concentrated or when a higher approved dosage of drug can be used; also indicates a “buffer zone” that should prevent small, uncontrolled, technical factors from causing major discrepancies in interpretations Project: VET05
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intermediate antimicrobial susceptibility test interpretive category a category that implies that an infection due to the isolate may be appropriately treated in body sites where the drugs are physiologically concentrated; also indicates a ¨buffer zone¨ that should prevent small, uncontrolled, technical factors from causing major discrepancies in interpretations Project: VET04
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intermediate measures of precision precision under conditions where test results are obtained within the same facility but under changed conditions of operator, equipment, or time (modified from ISO 3534-1) Project: ISO 3534-1 NOTE 1: The changed conditions must be indicated; NOTE 2: Repeatability is considered the smallest measure of precision, due to no changes in conditions (such as within-run precision), and reproducibility is considered to be the largest measure, with all test conditions changed (such as interlaboratory precision). Intermediate measures (such as between run precision, between day precision, within laboratory precision, etc.) should lie between the extremes.
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intermediate precision (measure) precision under intermediate precision conditions Project: I/LA28
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intermediate precision (measurement) measurement precision under a set of intermediate precision conditions of measurement (modified from JCGM 200:2012) Alternate Term: intermediate measurement precision Project: ISO IEC Guide 99, EP05 NOTE: Relevant statistical terms are given in ISO 5725-3:1994 (JCGM 200:2012).
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intermediate precision precision under conditions intermediate between reproducibility conditions and repeatability conditions (ISO 15198) Project: ISO 15198, ISO CD 17593, ISO 15197, ISO DIS 17593, POCT14 NOTE 1: The concept of intermediate levels of precision is described in ISO 5725-3 (ISO 15198); NOTE 2: Quantitative measures of intermediate precision depend on the stipulated conditions; NOTE 3: Intermediate precision provides an indication of the variability that will be experienced by a user in typical use.
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intermediate precision condition of measurement condition of measurement, out of a set of conditions that includes the same measurement procedure, same location, and replicate measurements on the same or similar objects over an extended period of time, but may include other conditions involving changes (JCGM 200:2012) Alternate Term: intermediate precision condition Project: ISO IEC Guide 99, QMS24 NOTE 1: The changes can include new calibrations, calibrators, operators, and measuring systems (JCGM 200:2012); NOTE 2: A specification for the conditions should contain the conditions changed and unchanged, to the extent practical (JCGM 200:2012); NOTE 3: In chemistry, the term “inter-serial precision condition of measurement” is sometimes used to designate this concept (JCGM 200:2012).
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intermediate precision conditions conditions where test results or measurement results are obtained with the same method, on identical test/measurement items in the same test or measurement facility, under some different operating conditions (ISO 3534-2) Project: ISO 3434-2, EP05, EP15 NOTE 1: There are four elements to the operating conditions: time, calibration, operator, and equipment (ISO 3534-2); NOTE 2: A test house is an example of a test facility. A metrology laboratory is an example of a measurement facility (ISO 3534-2); NOTE 3: The changed elements in operating conditions must be noted; this could include precision estimates commonly called, for example, “between-run,” “within-day,” “between-day,” “within-device,” and “within-laboratory.”
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intermediate precision conditions conditions where independent test results are obtained with the same method on identical test items in the same laboratory or location, but where other variables such as operators, equipment, calibration, environmental conditions, and/or time intervals differ (ISO 15198) Project: ISO 17593, ISO 15197, ISO 15198 NOTE 1: Intended to measure precision in conditions leading to variability representative of actual use. Quantitative measures of intermediate precision depend on the stipulated conditions; NOTE 2: conditions where independent measurement results are obtained with the same measurement method on identical samples in the same location, but where other variables such as operators, equipment, calibration, environmental conditions, and/or time intervals differ (ISO 17593).
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intermediate precision conditions where test results or measurement results are obtained with the same method, on identical test/measurement items in the same test facility, under some different operating condition Project: I/LA28 NOTE 1: There are four elements to the operating conditions: time, calibration, operator, and equipment; NOTE 2: The changed elements in operating conditions must be noted; this could include precision estimates commonly called, for example, “between-run,” “within-day,” “between-day,” “within-device,” and “within-laboratory”; NOTE 3: The changed elements in operating conditions must be noted; this could include precision estimates commonly called, for example “between-run,” “within-day,” “between-day,” “within device,” and “within-laboratory.”
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intermediate precision of measurement measurement precision under conditions intermediate between reproducibility conditions and repeatability conditions (ISO 17593) Project: ISO 17593 NOTE 1: The concept of intermediate levels of precision is described in ISO 5725-3:1994; NOTE 2: Quantitative measures of intermediate precision depend on the stipulated conditions (ISO 17593); NOTE 3: Intermediate precision provides an indication of the variability that will be experienced by a user during typical use (ISO 17593).
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internal asset (or internal specimen) an asset or specimen that was accessioned into the performing (internal) laboratory’s information system without having been previously accessioned in any referring (external) laboratory’s information system Project: AUTO14 NOTE: In multi-institutional laboratory organizations, internal assets and specimens may have different universal location identifiers and second patient identifiers, but the accession or case identifier with its applicable part or container identifier and block or aliquot identifier are unique to the specimen within the performing (internal) laboratory’s information system and its downstream health care applications
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internal continuous response indication from an analyzer from examination of a sample Alternate Term: ICR Project: EP12, EP12-IG NOTE 1: In some qualitative examinations, this indication is compared with a cutoff value to produce the binary result; NOTE 2: Indication can also be called a signal.
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internal control a control that is placed in the same reaction tube as the specimen being analyzed Project: MM10 NOTE: An internal control will be subjected to exactly the same internal conditions and external parameters as any analyte present in the tube.
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internal control a nontarget sequence present in the same sample tube, which is coamplified to identify inhibition due to thermal cycler malfunction, suboptimal reagents or polymerase activity, or presence of inhibitory substances in the sample matrix; a defined amount of internal control can be used to quantify the target Project: MM17, MM06, MM19, MM20, MM22 NOTE: An internal control is placed in the same reaction tube as the specimen being analyzed. Thus, an internal control will be subjected to exactly the same internal conditions and external parameters as any measurand (analyte) present in the tube.
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internal control cells of known phenotypic expression present in the sample analyzed Project: H42, H43, H62 NOTE: Positive and/or negative expression and fluorescent intensity of such cells serve as process controls.
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internal control a nontarget sequence present in the same sample tube, which is coextracted and coamplified in order with the target sequence to identify poor extraction, inhibition due to thermal cycler malfunction, suboptimal reagents or polymerase activity, or presence of inhibitory substances in the sample matrix; a defined amount of internal control can be used to quantify the target Project: MM03, MM24 NOTE: An internal control is placed in the same reaction tube as the specimen being analyzed. Thus, an internal control will be subjected to exactly the same internal conditions and external parameters as any analyte present in the tube. Endogenous sample controls such as human gene targets can be used to assess that the specimen contains an adequate number of human cells.
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internal control cells of known phenotypic expression present in the sample analyzed that serve to define levels of antigenic expression and serve as an indicator of assay specifications being fulfilled Project: H52 NOTE: Positive and/or negative expression and fluorescent intensity of such cells serve as process controls.
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internal failure cost cost occurring before delivery or shipment of a product or before provision of service to the customer Project: QMS20
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internal laboratory see performing laboratory Project: AUTO14
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internal quality control for the purposes of CLSI document C50, internal quality control is the evaluation of analytical performance that includes quality control samples for which the analyst knows the expected measurement result Alternate Term: bench quality control Project: C50 NOTE 1: Internal quality control materials can be made by weighing or spiking a known amount of analyte into the matrix that will be used for the clinical analysis; NOTE 2: Internal quality control materials may also evaluate particular aspects of method performance, such as an analytical blank.
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internal quality control procedures run in association with the measurement of patients’ specimens to evaluate whether the analytical system is operating within predefined tolerance limits Project: H26
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internal quality control operational techniques and activities at the point of use that are used to fulfill requirements for quality of services Project: EN 375:1999 NOTE: Internal quality control comprises all steps of activity for production of results from collection of sample and measurement of a measurable quantity to reporting of result of measurement.
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internal quality control (IQC) set of procedures undertaken by laboratory staff for the continuous monitoring of operation and the results of measurements to decide whether results are reliable enough to be released Project: C51
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internal standard in mass spectrometry, a stable isotope-labeled version of the chemical analyte that is added to a sample at a known concentration during processing to allow for quantitation of the analyte Project: NBS04, NBS09
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internal standard a chemical substance that is added in a constant amount to calibration standards and unknown samples to correct for loss of analyte during preexamination preparation (eg, solid-phase extraction) or for matrix effects during analysis Project: C62, C64, C63
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international calibrator calibrator whose value of a quantity is not traceable to the International System of Units but is assigned by international agreement Project: MM06
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international conventional calibration material See international conventional calibrator.
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international conventional calibrator calibrator whose value of a quantity is not metrologically traceable to the SI but is assigned by international agreement (ISO 17511) Alternate Term: international conventional calibration material Project: ISO 17511 NOTE: The quantity is defined with respect to the intended clinical application (ISO 17511).
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international conventional calibrator calibrator whose quantity value is not metrologically traceable to the SI but is assigned by international agreement (ISO 15194) Alternate Term: international conventional calibration material Project: ISO 15194 NOTE: The quantity is defined with respect to the intended application (ISO 15194).
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international conventional calibrator calibrator whose quantity value is not metrologically traceable to the International System of Units but is assigned by international agreement (modified from ISO 17511) Project: EP30, EP32 NOTE: The quantity is defined with respect to the intended clinical application (ISO 17511).
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international conventional reference measurement procedure measurement procedure yielding values that are not metrologically traceable to the SI but which by international agreement are used as reference values for a defined quantity (ISO 17511) Project: ISO 17511, C45 NOTE: The quantity is defined with respect to the intended clinical application (ISO 17511).
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international harmonization protocol standardization process implemented by an international organization to achieve equivalence among measured quantity values for two or more in vitro diagnostic medical devices intended for examination of the same measurand for cases where there are no higher-order reference measurement procedures and no fit-for-purpose certified reference materials or international conventional calibrators (ISO 21151) Project: EP32 NOTE 1: A harmonization protocol can be used to achieve standardization of measured values for a stated measurand when there are no other higher-order reference system components that are suitable for use (ISO 21151); NOTE 2: A harmonization protocol defines the highest level of metrological traceability for the stated measurand (ISO 21151)
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international measurement standard measurement standard recognized by signatories to an international agreement and intended to serve worldwide (JCGM 200:2012) Project: ISO IEC Guide 99 EXAMPLE 1: The international prototype of the kilogram (JCGM 200:2012); EXAMPLE 2: Chorionic gonadotrophin, World Health Organization (WHO) 4th international standard 1999, 75/589, 650 International Units per ampoule (JCGM 200:2012); EXAMPLE 3: VSMOW2 (Vienna Standard Mean Ocean Water) distributed by the International Atomic Energy Agency (IAEA) for differential stable isotope amount-of-substance ratio measurements (JCGM 200:2012).
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international measurement standard standard recognized by an international agreement to serve as the basis for assigning values to other standards of the quantity concerned Alternate Term: international standard Project: ISO 17511
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international measurement standard standard recognized by an international agreement to serve as the basis for assigning values to other standards of the quantity concerned
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international normalized ratio patient’s prothrombin time measurement result, which has been standardized for the potency of the thromboplastin used in the measurement procedure and expressed relative to a normal population average (ISO 17593) Project: ISO 17593, H54 NOTE 1: For a discussion of the use of international normalized ratio, see Poller et al. (ISO 17593); NOTE 2: It is standardized using a World Health Organization international reference thromboplastin preparation, and determined using the equation: INR = RISI, where R is the prothrombin time ratio obtained with the working thromboplastin; NOTE 3: Patient’s prothrombin time test result expressed as a ratio to a normal population which has been standardized (or normalized) for the potency of the thromboplastin used in the assay (modified from ISO 17593); NOTE 4: INR = (Plasma PT÷MNPT)ISI.
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international normalized ratio patient’s prothrombin time (PT) test results expressed as a ratio to the mean normal prothrombin time (MNPT) standardized (or normalized) for the potency of the thromboplastin used in the assay (modified from ISO 17593) Project: H21 NOTE: INR = (Plasma PT ÷ MNPT)ISI.
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international normalized ratio the patient’s prothrombin time test result expressed as a ratio to a mean normal prothrombin time, which has been standardized (or normalized) for the potency of the thromboplastin used in the assay (modified from ISO 17593) Project: H47, H57 NOTE: INR = (Plasma PT÷MNPT)ISI.
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international normalized ratio expression of the patient’s prothrombin time expressed as a ratio to a normal population control that has been standardized (or normalized) for the potency to the thromboplastin used in the assay Project: POCT14 NOTE 1: The international normalized ratio is determined by using the equation INR = RISI, in which R is the prothrombin time ratio obtained with the working thromboplastin; NOTE 2: The international sensitivity index should be determined by standard protocols according to World Health Organization guidelines and provided by the manufacturer to the user for a particular reagent/instrument combination or point-of-care coagulation testing system.
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international reference preparation a thromboplastin with defined biological activity used to calibrate other reference preparations and secondary or manufacturer’s standards Project: H54, H47 NOTE 1: There are three species of international reference preparation: bovine, rabbit, and human, which can be produced from original biological sources or other recombinant sources; NOTE 2: International reference preparations can only be used in combination with the manual technique (tilt-tube method, or other methods that have been validated); NOTE 3: World Health Organization and European Union certified reference material standards are examples of international reference preparations; NOTE 4: International reference preparations are also sometimes referred to as primary standards.
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international reference preparation (IRP) reference calibrator maintained by the World Health Organization (ISO 17593) Project: ISO 17593 NOTE: The IRP for thromboplastin is directly calibrated for potency against the original British comparative thromboplastin preparations used in the establishment of the INR system (ISO 17593).
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international reference preparation a substance that has been characterized by chemical or physical means and that provides a measure against which national reference preparations and calibrators can be controlled Project: H15 NOTE: International reference materials are not intended to be used in laboratory working procedures but serve as materials against which commercial products can be verified and evaluated.
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International Sensitivity Index a quantitative measure, in terms of the first International Reference Preparation of thromboplastin, human, combined, coded 67/40, of the responsiveness of a prothrombin-time system to the defect induced by oral anticoagulants (WHO 880) Project: H54, H47
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international sensitivity index a mathematical indicator of the responsiveness of a prothrombin time testing system to deficiencies of the vitamin K coagulation factors Project: POCT14 NOTE 1: It is the comparative slope used to calculate the international normalized ratio; NOTE 2: A low international sensitivity index indicates a highly responsive prothrombin time system, and a high international sensitivity index indicates a poorly responsive system; NOTE 3: International sensitivity index is determined by standard protocols according to World Health Organization guidelines and provided by the manufacturer to the user for a particular reagent/instrument combination.
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international sensitivity index (ISI) factor that allows the conversion of a patient's prothrombin time measurement result to international normalized ratio values (ISO 17593) Project: ISO 17593 NOTE: For a discussion of the use of ISI and INR, see Poller et al (ISO 17593).
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International Society of Blood Transfusion 128 (ISBT 128) the global standard published by the International Council for Commonality in Blood Banking Automation (ICCBBA) for the terminology, identification, coding and labeling of medical products of human origin (including blood, cell, tissue, milk, and organ products) Alternate Term: ISBT 128 Project: AUTO14 NOTE: The official name for the standard is ISBT 128 Standard Technical Specification
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international standard See international measurement standard
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International System of Quantities system of quantities based on the seven base quantities: length, mass, time, electric current, thermodynamic temperature, amount of substance, and luminous intensity (JCGM 200:2008) Alternate Term: ISQ Project: ISO IEC Guide 99 NOTE 1: This system of quantities is published in the ISO 80000 and IEC 80000 series Quantities and units (JCGM 200:2012); NOTE 2: The International System of Units (SI) (see 1.16) is based on the ISQ (JCGM 200:2012).
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International System of Units system of units, based on the International System of Quantities, their names and symbols, including a series of prefixes and their names andsymbols, together with rules for their use, adopted by the General Conference on Weights and Measures (CGPM) (JCGM 200:2012) Alternate Term: SI Project: ISO IEC Guide 99 NOTE 1: The SI is founded on the seven base quantities of the ISQ and the names and symbols of the corresponding base units that are contained in thefollowing table (JCGM 200:2012):
| Base quantity | Base unit | | Name | Symbol | | length mass time electric current thermodynamic temperature amount of substance luminous intensity | metre kilogram second ampere kelvin mole candela | m kg s A K mol cd | NOTE 2: The base units and the coherent derived units of the SI form a coherent set, designated the "set of coherent SI units" (JCGM 200:2012); NOTE 3: For a full description and explanation of the International System of Units, see the current edition of the SI brochure published by the Bureau International des Poids et Mesures (BIPM) and available on the BIPM website (JCGM 200:2012); NOTE 4: In quantity calculus, the quantity ‘number of entities’ is often considered to be a base quantity, with the base unit one, symbol 1 (JCGM 200:2012); NOTE 5: The SI prefixes for multiples of units and submultiples of units are (JCGM 200:2012): | Factor | Prefix | | Name | Symbol | | 1024 1021 1018 1015 1012 109 106 103 102 101 10-1 10-2 10-3 10-6 10-9 10-12 10-15 10-18 10-21 10-24 | yotta zetta exa peta tera giga mega kilo hecto deca deci centi milli micro nano pico femto atto zepto yocto | Y Z E P T G M k h da d c m μ n p f a z y |
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international system of units (SI) the coherent system of units adopted and recommended by the General Conference on Weights and Measures (CGPM) (VIM93) Alternate Term: SI Units Project: VIM93 NOTE: The SI is based at present on the following seven base units: | Quantity | SI base unit | | Name | Symbol | | length mass time electric current thermodynamic temperature amount of substance luminous intensity | metre kilogram second ampere kelvin mole candela | m kg s A K mol cd |
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international unit an arbitrary unit assigned to a certified reference material by an international organization that is generally accepted as competent Project: DL01 NOTE 1: Any recognized international organization can define an international unit; NOTE 2: An international unit of enzyme activity (U) is the amount of enzyme that will generate one molecule of product per minute under standard conditions; NOTE 3: The WHO-approved abbreviation for the international unit assigned to WHO International Biological Standards and WHO International Biological Reference Preparations under the control of the WHO expert Committee on Biological Standardization, is “IU,” rather then the SI recommendation “international unit”.
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Internet Engineering Task Force large, open international community of network designers, operators, vendors, and researchers concerned with the evolution of the Internet architecture and the smooth operation of the Internet Project: AUTO09 NOTE: It is open to any interested individual.
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Internet Protocol an Internet Standard protocol (version 4 and version 6) that moves datagrams (discrete sets of bits) from one computer to another across an internetwork but does not provide reliable delivery, flow control, sequencing, or other end-to-end services that Transmission Control Protocol provides (See IP address) (RFC 2828) Project: AUTO09
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Internet Protocol security 1) the name of the Internet Engineering Task Force working group that is specifying a security architecture and protocols to provide security services for Internet Protocol traffic; 2) a collective name for that architecture and set of protocols (Implementation of Internet Protocol security protocols is optional for Internet Protocol version 4, but mandatory for Internet Protocol version 6) (RFC 2828) Project: AUTO09
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interoperability the ability of two or more systems or components to exchange information and to use the information that has been exchanged Project: AUTO08
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interoperability refers to the architecture or standards that make it possible for diverse laboratory information systems/electronic health records to describe and transmit the same test result data, meaning, and context unambiguously across the digital or electronic health care ecosystem Project: AUTO17
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interpolate to insert, estimate, or find an intermediate term (in a sequence) Project: H54 NOTE 1: International normalized ratios above 4.5 would be extrapolated, while those between 1 and 4.5 would be interpolated.
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interpolation the process of determining the value of a function or quantity between two or more points at which it has prescribed values, such as between calibrator values Project: NRSCL08
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interpretive category (for breakpoints) category derived from microbiological characteristics, pharmacokinetic/pharmacodynamic indices, and/or clinical outcome data Project: VET02, VET09 NOTE 1: Minimal inhibitory concentration (MIC) or zone diameter values generated by a susceptibility test can be interpreted based on established breakpoints; NOTE 2: Categories used for breakpoints include susceptible, susceptible-dose dependent, intermediate, and resistant. EXAMPLE: Escherichia coli was isolated from a canine urine specimen, antimicrobial susceptibility testing (AST) was performed, and the MIC for enrofloxacin was 0.25 µg/mL. Using the breakpoints listed below, this E. coli isolate is categorized as susceptible because the enrofloxacin MIC is < 0.5 µg/mL. | Interpretive Category | Enrofloxacin Breakpoints | | MIC, µg/mL | Zone Diameter, mm | | Susceptible | ≤ 0.5 | ≥ 23 | | Susceptible-dose dependent | 1–2 | 17–22 | | Intermediate | 1–2 | 17–22 | | Resistant | ≥ 4 | < 16 |
MIC or zone diameter value breakpoints and interpretive categories are established per CLSI VET02 (or CLSI document M23 for human medical breakpoints) for categories of susceptible, intermediate, and resistant (and susceptible-dose dependent and nonsusceptible, when appropriate).
• susceptible (S) – a category defined by a breakpoint that implies that isolates with an MIC at or below or a zone diameter at or above the susceptible breakpoint are inhibited by the usually achievable concentrations of antimicrobial agent when the dosage recommended to treat the site of infection is used, resulting in likely clinical efficacy.
• susceptible-dose dependent (SDD) – a category defined by a breakpoint that implies that susceptibility of an isolate depends on the dosage regimen that is used in the patient. To achieve levels that are likely to be clinically effective against isolates for which the susceptibility testing results (either MICs or zone diameters) are in the SDD category, it is necessary to use a dosage regimen (ie, higher doses, more frequent doses, both, or extended infusion) that results in higher drug exposure than that achieved with the dose that was used to establish the susceptible breakpoint. Consideration should be given to the maximum, literature-supported dosage regimen, because higher exposure gives the highest probability of adequate coverage of an SDD isolate. CLSI VET01S Appendix E lists the doses used when establishing SDD categories. The drug label should be consulted for recommended doses and adjustment for organ function; NOTE: The SDD category may be assigned when PK/PD modeling and simulations show that the SDD dose will achieve therapeutic targets at this MIC range and the dose(s) listed is safe based on review of the literature or manufacturer’s data. This category also includes a buffer zone for inherent variability in test methods, which should prevent small, uncontrolled, technical factors from causing major discrepancies in interpretations, especially for drugs with narrow pharmacotoxicity margins. See CLSI VET01S Appendix F for additional information.
• intermediate (I) – a category defined by a breakpoint that includes isolates with MICs or zone diameters within the intermediate range that approach usually attainable blood and tissue levels and/or for which response rates may be lower than for susceptible isolates; NOTE: The intermediate category implies clinical efficacy in anatomical sites where the drugs are physiologically concentrated or when a higher-than-normal dosage of a drug can be used. The intermediate category includes a buffer zone for inherent variability in test methods, which should prevent small, uncontrolled, technical factors from causing major discrepancies in interpretations, especially for drugs with narrow pharmacotoxicity margins.
• resistant (R) – a category defined by a breakpoint that implies that isolates with an MIC at or above or a zone diameter at or below the resistant breakpoint are not inhibited by the usually achievable concentrations of the agent with normal dosage schedules and/or that demonstrate MICs or zone diameters that fall in the range in which specific microbial resistance mechanisms are likely, and clinical efficacy of the agent against the isolate has not been reliably shown in isolates with similar phenotypes.
• nonsusceptible (NS) – a category used for isolates for which only a susceptible breakpoint is designated because of the absence or rare occurrence of resistant strains. Isolates for which the antimicrobial agent MICs are above or the zone diameters are below the value indicated for the susceptible breakpoint should be reported as nonsusceptible; NOTE 1: An isolate that is interpreted as nonsusceptible does not necessarily mean that the isolate has a resistance mechanism. It is possible that isolates with MICs above the susceptible breakpoint that lack resistance mechanisms may be encountered within the wild-type distribution after the time the susceptible-only breakpoint was set; NOTE 2: The term “nonsusceptible” should not be used when the text is describing an organism/drug category with intermediate and resistant interpretive categories. Isolates that are in the categories of “intermediate” or “resistant” could be called “not susceptible” rather than “nonsusceptible.”
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interpretive category (for breakpoints) category derived from microbiological characteristics, pharmacokinetic/pharmacodynamic parameters, and/or clinical outcome data, when available Project: M38, M100, M02, M07, M23, VET01, M11, M44, M39 NOTE 1: Minimal inhibitory concentration (MIC) or zone diameter values generated by a susceptibility test can be interpreted based on established breakpoints; NOTE 2: Categories used for breakpoints include susceptible, susceptible-dose dependent, intermediate, resistant, and nonsusceptible; NOTE 3: See breakpoint; NOTE 4: Also applies to wild-type and non-wild-type; see epidemiological cutoff value.
EXAMPLE: | | Breakpoints | Breakpoints | | Interpretive Category | MIC, µg/mL | Zone Diameter, mm | | Susceptible | ≤ 4 | ≥ 20 | | Susceptible-dose dependent | 8–16 | 15–19 | | Intermediate | 8–16 | 15–19 | | Resistant | ≥ 32 | ≤ 14 | | Nonsusceptible | > 1 | < 17 |
MIC or zone diameter value breakpoints and interpretive categories are established per CLSI M23 for categories of susceptible, intermediate, and resistant (and susceptible-dose dependent and nonsusceptible, when appropriate). CLSI susceptible (S) or susceptible-dose dependent (SDD) breakpoints added or revised since 2010 have been based on specific dosage regimen(s); these dosage regimens are listed in CLSI M100 Table 2, Dosages. Antimicrobial Agent Dosage Regimens Used to Establish Susceptible or Susceptible-Dose Dependent Breakpoints (referred to as “CLSI M100 Table 2 Dosages”).
• susceptible (S) – a category defined by a breakpoint that implies that isolates with an MIC at or below or a zone diameter at or above the susceptible breakpoint are inhibited by the usually achievable concentrations of antimicrobial agent when the dosage recommended to treat the site of infection is used, resulting in likely clinical efficacy.
• susceptible-dose dependent (SDD) – a category defined by a breakpoint that implies that susceptibility of an isolate depends on the dosage regimen that is used in the patient. To achieve levels that are likely to be clinically effective against isolates for which the susceptibility testing results (either MICs or zone diameters) are in the SDD category, it is necessary to use a dosage regimen (ie, higher doses, more frequent doses, or both or extended infusion) that results in higher drug exposure than that achieved with the dose that was used to establish the susceptible breakpoint. Consideration should be given to the maximum, literature-supported dosage regimen because higher exposure gives the highest probability of adequate coverage of an SDD isolate. CLSI M100 Table 2 Dosages lists the doses used when establishing SDD categories. The drug label should be consulted for recommended doses and adjustment for organ function; NOTE: The SDD category may be assigned when doses well above those used to calculate the susceptible breakpoint are supported by the literature, widely used clinically, and/or approved and for which sufficient data to justify the designation exist and have been reviewed. This category also includes a buffer zone for inherent variability in test methods, which should prevent small, uncontrolled, technical factors from causing major discrepancies in interpretations, especially for drugs with narrow pharmacotoxicity margins. See CLSI M100 appendixes for additional information.
• intermediate (I) – a category defined by a breakpoint that includes isolates with MICs or zone diameters within the intermediate range that approach usually attainable blood and tissue levels and/or for which response rates may be lower than for susceptible isolates; NOTE: An I with a ^ in CLSI M100 Tables 2 indicates agents that have the potential to concentrate in the urine. The I^ is for informational use only. The decision to report I^ is best made by each laboratory based on institution-specific guidelines and in consultation with appropriate medical personnel. The I category also includes a buffer zone for inherent variability in test methods, which should prevent small, uncontrolled, technical factors from causing major discrepancies in interpretations, especially for drugs with narrow pharmacotoxicity margins.
• resistant (R) – a category defined by a breakpoint that implies that isolates with an MIC at or above or a zone diameter at or below the resistant breakpoint are not inhibited by the usually achievable concentrations of the agent with normal dosage schedules and/or that demonstrate MICs or zone diameters that fall in the range in which specific microbial resistance mechanisms are likely, and clinical efficacy of the agent against the isolate has not been reliably shown in treatment studies.
• nonsusceptible (NS) – a category used for isolates for which only a susceptible breakpoint is designated because of the absence or rare occurrence of resistant strains. Isolates for which the antimicrobial agent MICs are above or the zone diameters are below the value indicated for the susceptible breakpoint should be reported as nonsusceptible; NOTE 1: An isolate that is interpreted as nonsusceptible does not necessarily mean that the isolate has a resistance mechanism. It is possible that isolates with MICs above the susceptible breakpoint that lack resistance mechanisms may be encountered within the wild-type distribution after the time the susceptible-only breakpoint was set; NOTE 2: The term “nonsusceptible” should not be used when the text is describing an organism-drug category with intermediate and resistant interpretive categories. Isolates that are in the categories of “intermediate” or “resistant” could be called “not susceptible” rather than “nonsusceptible.”
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interpretive category for mycobacteria, category derived from microbiological characteristics and clinical outcome data, when available Project: M24 NOTE 1: For mycobacteria, critical concentration and minimal inhibitory concentration (MIC) values generated by a susceptibility test can be interpreted based upon established breakpoints; NOTE 2: For mycobacteria, two different categories, critical concentration and MIC, have been used to categorize the in vitro results; NOTE 3: For members of the Mycobacterium tuberculosis complex, when tested against the lower concentration of some agents, the critical concentration category is applied. Testing of an additional higher concentration may also be recommended for some agents. However, there is no “intermediate” interpretive category when the critical concentration category is applied, even when testing is performed both at the critical concentration and the additional higher concentration; NOTE 4: For nontuberculous mycobacteria and for the aerobic actinomycetes, only the MIC breakpoint is applied; NOTE 5: See breakpoint. EXAMPLE*: | Interpretive Category | Breakpoints† | | MIC, µg/mL | Critical Concentration, µg/mL‡ | | Susceptible | £ 4 | 1 (no growth) | | Intermediate | 8–16 | – | | Resistant | ³ 32 | 1 (growth) | * The example shown applies to a commercial short-incubation broth system. † Formerly “interpretive criteria.” ‡ Breakpoint depends on the method used and whether the organism grows at a single concentration. • susceptible (S) – a category defined by a breakpoint that implies that isolates with an MIC at or below the susceptible breakpoint are inhibited by the usually achievable concentrations of antimicrobial agent when the dosage recommended to treat the site of infection is used, resulting in likely clinical efficacy; NOTE: For critical concentration, a level of susceptibility that is not significantly different from that of wild-type strains from patients who have not been treated with the drug is needed, so that the strain is likely to show clinical responsiveness to the drug. • intermediate (I) – for MICs only, a category defined by a breakpoint that includes isolates with MICs within the intermediate range that approach usually attainable blood and tissue levels and for which response rates may be lower than for susceptible isolates; NOTE: The intermediate category implies clinical efficacy in body sites where the drugs are physiologically concentrated or when a higher-than-normal dosage of a drug can be used. This category also includes a buffer zone, which should prevent small, uncontrolled, technical factors from causing major discrepancies in interpretations, especially for drugs with narrow pharmacotoxicity margins. • resistant (R) – a category defined by a breakpoint that implies that isolates with an MIC at or above the resistant breakpoint are not inhibited by the usually achievable concentrations of the agent with normal dosage schedules and/or that demonstrate MICs that fall in the range in which specific microbial resistance mechanisms are likely, and clinical efficacy of the agent against the isolate has not been reliably shown in treatment studies; NOTE: For critical concentration, resistance is defined as diminished susceptibility of a strain that differs from wild-type strains from patients who have not been treated with the drug, so that the strain is unlikely to show clinical responsiveness to the drug.
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interpretive category (for epidemiological cutoff values) category derived from microbiological characteristics Project: VET01, VET02, VET09 NOTE 1: Minimal inhibitory concentration (MIC) or zone diameter values generated by a broth dilution or disk diffusion test can be interpreted based on established epidemiological cutoff values (ECVs); NOTE 2: Categories used for ECVs include wild-type and non-wild-type.
EXAMPLE: | Interpretive Category | ECVs | | MIC, µg/mL | Zone Diameter, mm | | Wild-type Non-wild-type | ≤ 4 ≥ 8 | ≥ 20 ≤ 19 | |
- wild-type (WT) – an interpretive category defined by an ECV that describes the microbial population with no phenotypically detectable mechanisms of resistance or reduced susceptibility for the antimicrobial agent being evaluated.
- non-wild-type (NWT) – an interpretive category defined by an ECV that describes the microbial population with phenotypically detectable mechanisms of resistance and reduced susceptibility for the antimicrobial agent being evaluated.
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interstitial fluid a liquid found between the cells of the body that provides much of the liquid environment of the body: extracellular fluid Project: POCT13
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interstitial monitoring the process of gathering information about the concentration of an analyte in the extracellular fluid Project: POCT05
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interval set of all values lying between and sometimes including one or both of the lower limiting value or higher limiting value
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interval the range within which some quantity or concept applies, stated as the lowest and highest values involved Project: NRSCL08 NOTE: See also range.
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intervention (for newborn screening) specific newborn screening follow-up activity (eg, clinical assessment, medical management, monitoring, treatments) aimed at preventing morbidity and mortality in at-risk or affected newborns Project: NBS02, NBS03, NBS05, NBS13, NBS10 Source: Newborn Screening Glossary NOTE: See follow-up.
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intracellular cytokine staining a laboratory technique in which the following steps are performed: 1) cells are stimulated to produce cytokines in the presence of protein secretion inhibitors, permitting cytokines to accumulate inside the producing cells; 2) the cells are stained with antibodies for markers on their surface (eg, anti-CD3, anti-CD4, or anti-CD8), washed, and fixed; 3) the cells are permeabilized, and then stained with the anticytokine antibody, followed by a wash step; and 4) the cells are then analyzed by flow cytometry Project: I/LA26 NOTE: This term is synonymous with intracellular cytokine flow cytometry.
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intraepithelial lesion Bethesda System terminology for a subgroup of epithelial cell abnormalities that include low-grade squamous intraepithelial lesion, koilocytosis, human papillomavirus effect, and high-grade squamous intraepithelial lesion Project: GP15 NOTE: Atypical squamous cells of undetermined significance, high-grade squamous intraepithelial lesion, atypical glandular cells, invasive carcinomas, sarcomas, and other neoplasms are not included among intraepithelial lesions.
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intrinsic blood coagulation pathway the sequential activation of factors XII, XI, and IX in the presence of prekallikrein and cofactors high-molecular-weight kininogen and factor VIII triggered by contact factor Project: POCT14
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intrinsic error (of a measuring instrument) error of a measuring instrument, determined under reference conditions (VIM93)
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intrinsic factor pathway involves Factors VIII, IX, XI, XII (Hageman factor), prekallikrein, and high molecular weight kininogen Project: H48 NOTE 1: This pathway merges with the extrinsic pathway intothe common pathway; NOTE 2: The intrinsic pathway is activated when Factor XII, prekallikrein, and high molecular weight kininogen bind to a negatively charged “foreign” surface exposed to blood. Then, it sequentially activates Factors XI, IX, X, then Factor II (prothrombin to thrombin), which converts fibrinogen to fibrin; NOTE 3: The activated partial thromboplastin time measures the intrinsic and common pathways.
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intrinsic measurement standard measurement standard based on an inherent and reproducible property of a phenomenon or substance (JCGM 200:2012) Alternate Term: intrinsic standard Project: ISO IEC Guide 99 EXAMPLE 1: Triple-point-of-water cell as an intrinsic measurement standard of thermodynamic temperature (JCGM 200:2012); EXAMPLE 2: Intrinsic measurement standard of electric potential difference based on the Josephson effect (JCGM 200:2012); EXAMPLE 3: Intrinsic measurement standard of electric resistance based on the quantum Hall effect (JCGM 200:2012); EXAMPLE 4: Sample of copper as an intrinsic measurement standard of electric conductivity (JCGM 200:2012); NOTE 1: A quantity value of an intrinsic measurement standard is assigned by consensus and does not need to be established by relating it to another measurement standard of the same type. Its measurement uncertainty is determined by considering two components: the first associated with its consensus quantity value and the second associated with its construction, implementation, and maintenance (JCGM 200:2012); NOTE 2: An intrinsic measurement standard usually consists of a system produced according to the requirements of a consensus procedure and subject to periodic verification. The consensus procedure may contain provisions for the application of corrections necessitated by the implementation (JCGM 200:2012); NOTE 3: Intrinsic measurement standards that are based on quantum phenomena usually have outstanding stability (JCGM 200:2012); NOTE 4: The adjective "intrinsic" does not mean that such a measurement standard may be implemented and used without special care or that such a measurement standard is immune to internal and external influences (JCGM 200:2012).
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intrinsic phase blood coagulation pathway the sequential activation of Factors XII, XI, and IX in the presence of Prekallikrein and cofactors HMW-Kininogen and Factor VIII triggered by contact factor
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intrinsic resistance inherent or innate (not acquired) antimicrobial resistance, which is reflected in wild-type antimicrobial patterns of all or almost all representatives of a microbial species Project: VET09, M39
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intron a noncoding sequence of DNA that is initially copied into RNA but is cut out of the final RNA transcript Project: NBS05
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intron a segment of a gene that is initially transcribed but is then removed from within the primary RNA transcript by splicing together the sequences (exons) on either side of it Project: MM19
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in-use stability duration of time over which the performance of a product within its expiry date remains within specified limits after the container system supplied by the manufacturer is opened and the product is put into use under standard operating conditions (eg, storage on the instrument) Project: EP25, EP30, EP39
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invariant gene a gene with an expression level that is unchanging in a given tissue under experimental conditions or in the normal and diseased state Project: MM16
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inventory in Automation, the materials available on an instrument used to support the operation of that instrument Project: AUTO01, AUTO02, AUTO03
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investigational breakpoint a breakpoint for an antimicrobial agent in development and for which there is no regulatory approval. This breakpoint is based on relevant microbiological and pharmacokinetic/pharmacodynamic data and is not published in CLSI documents Project: M23
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investigational use only product labeling for any product that is being evaluated under strictly controlled clinical trial protocol by a sponsor with signed principal investigator certification Project: MM07 NOTE: These slides should be labeled “for investigational use only,” and are subject to an inspection by a national regulatory body.
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investigator person responsible for the execution of the performance evaluation at a certain location (ISO 20776-2) Project: ISO 20776-2
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ion activity the ion concentration corrected for deviations from ideal behavior; 1) specific activity - a measurable event per unit mass per unit time; 2) activity concentration (of a radioactive material) - the activity of the contained radionuclide to the volume of material
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ion current the intensity of an ion beam produced in the source, passed through the mass analyzer, and measured by the detector Project: C43, C50
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ion exchange a reversible process by which ions are interchanged between an insoluble material and a liquid with no substantial structural changes of the material Project: ASTM08 NOTE: See also deionization.
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ion exchange a reversible chemical reaction between a solid containing immobilized ionic sites (ion exchanger) and a fluid (often water) by means of which ionized species may be exchanged from one substance to another Project: GP40
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ion ratio the ratio of signal intensities at two m/z values Project: C43, C64 NOTE 1: Usually expressed as a percentage; NOTE 2: The ratio may be determined from the ratio of chromatographic peak areas or peak heights, or may be calculated from a single mass spectrum.
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ion suppression a decrease in the quantity of ions that ultimately reaches the mass detector Project: C50
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ion suppression a matrix effect in mass spectrometry that results in a diminishing of analytical signal, independent of the analytical sensitivity or selectivity of the mass analyzer Project: C62, C63
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ion transition ratio the ratio of intensities between two ion populations arising from a common precursor ion Project: C64 NOTE: The ratio may be determined from the ratio of chromatographic peak areas or maximum chromatographic peak heights or may be calculated from peak heights in a single mass spectrum.
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ion trapping the accumulation of high concentrations of a compound across a cell membrane due to a pH differential Project: C52 NOTE: Ion trapping often occurs in the gastric mucosa when a nonionized acidic drug is absorbed from the gastric contents and becomes ionized and trapped within the cells.
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ionic conduction the conductive (ie, electrophoretic) migration of dissolved ions in the applied electromagnetic field Project: GP28
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ionization efficiency a measure of the fraction of a particular set of molecules delivered to an ion source that is actually ionized Project: NBS04, NBS09 NOTE: The ionization efficiency depends on the conditions set for the ionization source, the chemical nature of the molecule (functional groups), and the chemical environment around the analyte.
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ionized calcium the concentration of calcium ions in whole blood that is not bound by protein or other molecules Project: C39 NOTE: This parameter, also called “free” or “ionic” calcium, exists in the blood plasma water.
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ionomycin a calcium ionophore and potent T-cell activator Project: I/LA26
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iontophoresis the migration of small ions in an electrical field Project: C34, NBS05 NOTE: In the sweat chloride test, pilocarpine is iontophoresed into the skin to stimulate sweating.
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IP address a computer’s internetwork address that is assigned for use by the Internet Protocol and other protocols (RFC 2828) Project: AUTO09
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ipsilateral on the same side (eg, arm on the same side as the breast mass) Project: GP20
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irreplaceable specimen a specimen that is difficult to collect (invasive and/or surgically removed) and cannot be replaced by a repeat specimen, such as a lymph node or spleen Project: H42, H43 NOTE: Such specimens may be analyzed even when there is poor viability, since another identical diagnostic specimen cannot be obtained. This is in contrast to blood, which can be easily replaced with minimal impact on the patient’s health. There are instances in which a blood sample may be considered irreplaceable, such as when recollection may delay diagnosis of an acute leukemia, or therapy may already have been initiated based on presumptive clinical diagnosis.
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ISE half-cell one-half of an overall electrochemical cell whose electrical potential varies in accordance with the Nernst Equation, as the concentration or activity of a single, desired species in solution is changed Project: C39
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ISO International Organization for Standardization (www.iso.org), a network of the national standards institutes of 151 countries, on the basis of one member per country, with a Central Secretariat in Geneva, Switzerland, that coordinates the system Project: POCT02
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ISO 8859 acronym for the International Organization for Standardization’s eight-bit character encoding that is also called code page1252, Western European, or Latin 1 Project: AUTO01, AUTO02, AUTO03
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ISO/IEEE 11073 a family of standards for medical device communications that are optimized for the acute care setting Project: POCT01 NOTE: When they are harmonized with IEEE 1073 standards, the designation is ISO/IEEE 11073. (See IEEE 1073.)
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isoallergens proteins (allergens) that are essentially identical except for minor differences in their primary amino acid composition or substituted side chains Project: I/LA34, I/LA20
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isoallotype a genetic marker that occurs on more than one immunoglobulin isotype Project: DL01
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isobaric the property of atomic or molecular species having the same nominal mass but different exact masses Project: C64
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isochronous protocol testing protocol designed so that a product that underwent exposure to various storage durations under various conditions is tested by the same operator, on the same instrument in the same run, to eliminate sources of variation such as calibration to calibration, instrument to instrument, and operator to operator Project: EP25, EP30 NOTE: This protocol enables estimation of stability claims with a reduced amount of data or with reduced uncertainty.
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isoform one of several forms of a single protein that has the same antigenic structure but differs in minor amino acid content and/or steric structure Project: DI01, EP34
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isolate a pure culture of bacteria obtained by subculture of a single colony taken from a primary culture plate and presumed to be derived from a single organism Project: MM24 NOTE: “Strain” should not be used as a synonym for “isolate.”
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isolate sequence sequence obtained from the sample's bacterial or fungal isolate Project: MM18
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isolation See purification Alternate Term: purification Project: MM03
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isolation separation of ill or contaminated persons or affected baggage, containers, conveyances, goods, or postal parcels from others in such a manner as to prevent the spread of infection or contamination Project: POCT16
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isothermal refers to a reaction or process performed at constant temperature Project: MM17
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isotope dilution the addition to a sample of a known amount of an internal standard NOTE: The known concentration of the internal standard may be used to calculate the concentration of the native analyte (compound) by determining the ratio of the signal intensity between the two compounds. The underlying principle assumes that the native compound and its labeled analog have the same chemical characteristics (eg, ionization efficiency, retention time, gas-phase physical characteristics [ie, fragmentation]) and differ only in mass.
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isotype the specific class and subclass of immunoglobulin molecule (eg, immunoglobulin G1) Project: I/LA26
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isotype an immunoglobulin heavy or light chain class or subclass characterized by antigenic determinants in the constant region Project: I/LA23, ILA29
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IT Infrastructure Technical Framework defines specific implementations of established standards to achieve integration goals that promote appropriate sharing of medical information to support optimal patient care Project: AUTO16
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IT support customer support staff familiar with computer hardware, operating system software, commercial off-the-shelf (COTS) software components, and networking environment
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JAHIS abbreviation for Japanese Association of Healthcare Information Systems Industry Project: AUTO01, AUTO02, AUTO03
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JCCLS abbreviation for Japanese Committee for Clinical Laboratory Standards Project: AUTO01, AUTO02, AUTO03
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JIS abbreviation for Japan Industry Standard Project: AUTO01, AUTO07, AUTO02, AUTO03
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job aid information excerpted from an approved procedure that is presented in a more readily viewable format; job aids are subject to document control Project: QMS02
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job introduction a program to introduce new personnel to the organization, the department, or area in which the person will work, the terms and conditions of employment, facilities, health and safety requirements (including fire and emergency), and occupational health services (modified from ISO 15189) Alternate Term: orientation Project: QMS16, QMS03 NOTE: A job introduction also has the key components of privacy, patient safety, and information management.
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JSCC abbreviation for Japanese Society for Clinical Chemistry Project: AUTO01, AUTO02, AUTO03
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jurisdiction the area for which a newborn screening program has legal authority and/or responsibility Project: NBS03, NBS10 Source: Newborn Screening Glossary
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just culture patient safety principles for achieving a culture in which frontline personnel feel comfortable disclosing errors—including their own (modified from Marx D. Patient Safety and the “Just Culture:” A Primer for Health Care Executives)
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justice the duty to treat all fairly, distributing the risks and benefits equably Project: GP45 NOTE 1: The principle of justice requires that the benefits and burdens of research be distributed fairly; NOTE 2: Vulnerable populations should not be targeted for research if other populations are also suitable; vulnerable populations and other populations, such as women, children, elderly, and minorities, should be offered participation in clinical trials to ensure access to new, beneficial, or potentially lifesaving treatments.
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karyosome concentrated clumps of chromatin material within the nucleus; position and morphology often used to differentiate intestinal protozoa Project: M28
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kerion a severe pustular inflammation involving the hair follicles Project: M54
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key elements the activities and tasks within a critical control point
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key indicator strains specific organisms recommended by the manufacturer of a microbial identification system that are necessary to test as part of the streamlined quality control process Project: M50, M52 NOTE: The organisms should be those the manufacturer has determined will best assess the performance of the microbial identification system and detect degradation of labile reagents and/or substrates.
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key operator an end user who has received training and technical knowledge beyond that of routine use Project: I/LA33 NOTE: This is often an individual who shares technical information and provides assistance with training, troubleshooting, and validation activities.
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key performance attributes metrics that have been selected to be the most critical indicators of the viability (stability) of a product over time Project: EP25, EP30
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kind level describes the type of laboratory equipment identifier, such as an in vitro diagnostic instrument model or a test reagent kit (eg, instrument type by manufacturer and model; a laboratory may have more than one) Project: AUTO17
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kind of quantity aspect common to mutually comparable quantities (JCGM 200:2012) Alternate Term: kind Project: ISO IEC Guide 99 NOTE 1: The division of the concept of ‘quantity’ according to ‘kind of quantity’ is to some extent arbitrary (JCGM 200:2012); EXAMPLE 1: The quantities diameter, circumference, and wavelength are generally considered to be quantities of the same kind, namely of the kind of quantity called length (JCGM 200:2012); EXAMPLE 2: The quantities heat, kinetic energy, and potential energy are generally considered to be quantities of the same kind, namely of the kind of quantity called energy (JCGM 200:2012); NOTE 2: Quantities of the same kind within a given system of quantities have the same quantity dimension. However, quantities of the same dimension are not necessarily of the same kind (JCGM 200:2012); EXAMPLE 3: The quantities moment of force and energy are, by convention, not regarded as being of the same kind, although they have the same dimension. Similarly for heat capacity and entropy, as well as for number of entities, relative permeability, and mass fraction (JCGM 200:2012); NOTE 3: In English, the terms for quantities in the left half of the table in 1.1, Note 1, are often used for the corresponding ‘kinds of quantity.’ In French, the term "nature" is only used in expressions such as "grandeurs de même nature" (in English, "quantities of the same kind") (JCGM 200:2012).
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kit all components of a test that are packaged together (US CFR 493 February 28, 1992)
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kit set of components that are packaged together and intended to be used to perform a specific IVD examination (ISO 18113-1)
Project: ISO 18113-1, ISO 18113-2, ISO 18113-3 NOTE 1: Kit components can include reagents (such as antibodies, enzymes, buffer, and diluents), calibrators, controls, and other articles and materials (ISO 18113-1); NOTE 2: Adapted from EN 375:2001, definition 3.10 (ISO 18113-1).
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kit set of components of an IVD assay packaged together (ISO/CD 18112-1) Project: ISO CD 18112-1 NOTE: Kit components may include antibodies, enzymes, buffer, diluents, calibrators, and control materials. (ISO/CD 18112-1)
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knowledge the intelligent use of information by an organization or individual Project: QMS12
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known valid biomarker biomarker that is widely accepted in the medical and scientific community for predicting clinical or preclinical outcomes NOTE: Supporting data are so strong that these biomarkers are used in conjunction with approved molecular targeted treatment. They are measured in analytical test systems with well-established performance characteristics for which there is widespread agreement about the significance for the test results.
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label printed, written, or graphic information placed on a medical device or its container (ISO 18113-1) Project: ISO 15197, EN 375, GP39, ISO CD 18113-1, ISO CD 18113-2, ISO CD 18113-3, ISO/DIS 17593 NOTE 1: A label permanently affixed to a product is considered marking. See the definition of marking; NOTE 2: A label permanently affixed to an in vitro diagnostic instrument is considered marking (ISO 18113-1); NOTE 3: Adapted from EN 375:2001, definition 3.12 (ISO 18113-1).
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label The Global Harmonization Task Force defines a label as information provided upon the medical device itself or on its packaging; Australian, EU, Japanese, and US definitions and/or common usage are consistent with the GHTF definition; The Canadian Food and Drugs Act defines label to include "any legend, work or mark attached to, included in, belonging to or accompanying any food, drug, cosmetic, device or package, "i.e., what GHTF and other countries inclusively term "labelling" and what the EU terms "information supplied by the manufacturer" (EN 375) Project: ISO CD 18112-1
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label 1) the display of written, printed, or graphic matter on the immediate container of any article (US Food, Drug, and Cosmetic Act, Section 201[k]); 2) in automation, the paper and attached adhesive coating on which the bar code and other human-readable information is printed; 3) a piece of paper or other material to be affixed to a container or article, on which is printed a legend, information concerning the product, or addresses; 4) one or more characters within or attached to a set of data, that identify or describe the data (IEEE 610.12); 5) printed, written, or graphic information placed on a device or container (ISO 15197) Project: AUTO07, AUTO02, AUTO03, AUTO12, AUTO14 NOTE: It may also be printed directly on the container (ASTM D966).
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label 1) in automation, the paper and attached adhesive coating on which the bar code and other human readable information is printed; 2) in computer software, a name or identifier assigned to a computer program statement to enable other statements to refer to that statement; 3) one or more characters within or attached to a set of data, that identify or describe the data (IEEE 610.12) Project: AUTO01, AUTO02, AUTO03
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label in immunology, a substance that is linked to a reagent (eg, antigen or antibody) to facilitate detection in an immunoassay system using either a measurable property of the label or an entity produced by the label Project: I/LA28, ILA18, LA01 NOTE: In ELISA and EIA, the label is the enzyme; in fluorescence-linked immunoassay, the label is a fluorescer; in radioimmunoassay, the label is the radionuclide.
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label printed, written, graphic, or other information placed on, or accompanying, an in vitro diagnostic medical device, including labels on any of its packaging, user’s manuals, and package inserts (modified from ISO 18113-1) Project: M52 NOTE: The contents of all labels and other written, printed, or graphic matter upon any article or any of its containers or wrappers, or accompanying such article for products sold in the United States, are regulated by the US Food and Drug Administration (US Food, Drug, and Cosmetic Act, § 321[m]).
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labeling all labels and other written, printed, or graphic matter upon any article or any of its containers or wrappers, or accompanying such article (US Food, Drug, and Cosmetic Act, Section 201 (m)) Project: H05, LA01, M50
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labelling See information supplied by the manufacturer
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labelling The Global Harmonization Task Force defines a label as information provided upon the medical device itself or on its packaging;Australian, EU, Japanese, and U.S. definitions and/or common usage are consistent with the GHTF definition; The Canadian Food and Drugs Act defines label to include "any legend, work or mark attached to, included in, belonging to or accompanying any food, drug, cosmetic, device or package, "ie, what GHTF and other countries inclusively term "labelling" and what the EU terms "information supplied by the manufacturer" (ISO/TR 18112) Project: ISO/TR 18112
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labelling all printed, written, graphic, or other information affixed to, or accompanying an in vitro diagnostic medical device, including labels on any of its packaging, users’ manuals, and package inserts (modified from ISO 18113-1) Project: ISO 15197
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laboratory a facility for the biological, microbiological, serological, chemical, immunohematological, biophysical, cytological, pathological, or other examination of materials derived from the human body for the purpose of providing information for the diagnosis, prevention, or treatment of any disease; or impairment of, or the assessment of the health of human beings (42 CFR 493) Project: I/LA33 NOTE: For this document, it is any location or facility that performs immunohematological testing. This may include, but is not limited to, transfusion services, donor centers, reference laboratories, immunohematology reference laboratories, hospitals, etc.
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Laboratory Analytical Workflow profile covers the exchange of information related to patient and quality control test orders and results between in vitro diagnostic testing systems and health informatics systems Project: AUTO16, AUTO17
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laboratory automation system a system of information and hardware technology that allows the operation of the medical laboratory process without significant operator intervention Project: AUTO01, AUTO02, AUTO10, I/LA33, AUTO12, QMS04, AUTO16, AUTO14 NOTE 1: Typical functionality includes information system control of the instruments through direct laboratory automation system interfacing, including any technology that manipulates the specimen (ie, centrifuge); transportation of the specimen; result evaluation, repeat testing, and reflex testing; and quality assessment and results reporting; NOTE 2: Laboratory automation system are a type of laboratory middleware.
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laboratory capability physical, environmental, and information resources, personnel, skills, and expertise available for the examinations in question (ISO 15189) Project: ISO 15189 NOTE: A review of laboratory capability could include results of earlier participation in interlaboratory comparisons or external quality assessment schemes or the running of trial examination programs, or all of these, in order to demonstrate uncertainties of measurement, limits of detection, etc. (ISO 15189)
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laboratory device a category of actors in the Laboratory Device Automation Profile Project: AUTO16 NOTE: A laboratory device is either an analyzer or a pre- and/or postprocessor.
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Laboratory Device Automation Profile strictly covers the workflow between automation managers and laboratory devices operated by the medical laboratory staff Project: AUTO16 NOTE: Devices operated by the clinical ward staff are supported by the Laboratory Point-of-Care Testing Profile and are therefore out of the Laboratory Device Automation Profile’s scope.
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laboratory director competent person(s) with responsibility for, and authority over, a laboratory (ISO 15189) Project: ISO 15189, H26, POCT08, EP23, QMS14, POCT15 NOTE 1: The person or persons referred to are designated collectively as the “laboratory director” (ISO 15189); NOTE 2: National, regional, and local regulations may apply with regard to qualifications and training (ISO 15189); NOTE 3: This person has final responsibility for the quality and appropriateness of laboratory testing; NOTE 4: Typically, the laboratory director is a physician or doctoral scientist who can make decisions about the medical and technical aspects of testing.
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Laboratory Equipment Control Interface Specification a high-level protocol that defines message content for standard behaviors or interactions for remote control of analytical instruments and devices (ASTM E1989) Project: AUTO01, AUTO02
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laboratory information system the computer system used to manage data collected and generated by a medical laboratory, frequently integrated into a hospital or health care information system Project: M39
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laboratory information system the information system that is responsible for management of data regarding patient specimen identification, tests requested, results reported, quality control testing, and other aspects of sample analysis Project: AUTO02, AUTO01, AUTO10, I/LA33, AUTO12, QMS26, AUTO16, AUTO17, AUTO14 NOTE 1: The laboratory information system interfaces directly with the laboratory automation system to communicate patient, visit, container, test orders, specimen status, and results about specific testing to be done; NOTE 2: Instrument or specimen processing and handling devices might be interfaced with the laboratory information system or the laboratory automation system to direct specific testing and to retrieve results for reporting; NOTE 3: The laboratory information system is frequently also interfaced to a clinical information system, such as an electronic health record, for use by physicians and other medical personnel; NOTE 4: Also referred to as laboratory information management system.
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laboratory information system a class of software that handles receiving, processing, and storing information generated by medical laboratory processes Project: POCT07 NOTE: These systems often must interface with instruments and other information systems, such as hospital information systems.
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laboratory information system information system responsible for managing data regarding patient/donor specimen identification, tests requested, results reported, quality control testing, and other aspects of sample analysis Alternate Term: laboratory information management system Project: MM19, MM26 NOTE 1: The laboratory information system interfaces directly with the laboratory automation system to communicate patient, visit, container, test orders, specimen status, and results about specific testing to be done; NOTE 2: Instrument or specimen processing and handling devices may be interfaced with the laboratory information system or the laboratory automation system to direct specific testing and to retrieve results for reporting; NOTE 3: The laboratory information system is frequently also interfaced to a clinical information system for use by clinicians and other medical personnel; NOTE 4: Also known as laboratory information management system.
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laboratory information system system that manages data related to test requisitions, patient demographics, and specimens Project: AUTO15 NOTE 1: A laboratory information system can interface with the laboratory analytical and process instruments as the data management center or serve for data collection, reporting, transmission, and archiving; NOTE 2: A laboratory information system can also interface with other information systems (eg, electronic health record system) for the transmission of test requisitions and final test results
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laboratory management person(s) who direct and manage the activities of a laboratory (ISO 15189) Project: ISO 15189, QMS14
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laboratory management a person or group of people who directs and controls a laboratory at the highest level Project: QMS29
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laboratory module standard distance calculated from two work countertops and the aisle space between them Project: QMS04
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laboratory oximeter a device using multiple wavelengths of light to determine the concentration of hemoglobin derivatives (eg, O2Hb, HHb, COHb, MetHb, and SulfHb) within a specimen of blood Project: POCT11 NOTE: Measurement of the percent saturation of hemoglobin by oxygen contained in arterial blood (SaO2) is used to validate SpO2.
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Laboratory Point-of-Care Testing Profile covers the workflow related to medical laboratory tests performed at the point of care or at the patient’s bedside, by ward staff, under supervision of the health care institution’s laboratory Project: AUTO16 NOTE 1: Within AUTO16’s scope, this term extends to devices supervised by a medical laboratory; NOTE 2: The point-of-care devices may be connected to a central data manager. This central system collects point-of-care tests and results related to patient specimens and quality control specimens, enables the supervision of the point-of-care testing process, and forwards the results to the supervising laboratory’s system.
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laboratory sample primary sample, or a subsample of it, as prepared for sending to or as received by the laboratory and intended for measurement (ISO 15193) Project: ISO 15193
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laboratory screening algorithm (for newborn screening) documented process for conducting laboratory-based screening tests, using a sequence of specified steps to determine the need for subsequent screening steps or actions and/or the final, reportable screening result and interpretation Project: NBS06, NBS09, NBS13, NBS02, NBS10 Source: Newborn Screening Glossary
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laboratory test medical procedure that involves testing a sample of blood, urine, or other substance from the body. Laboratory tests can help determine a diagnosis, plan treatment, establish whether a treatment is working, or monitor the disease over time Project: AUTO17
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laboratory test data embeds test related data, such as test ordered, test performed, and test result (observation) Project: AUTO17
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laboratory test ordered a single test or panel of tests ordered by a health care provider and performed by the laboratory on one or more specimens collected from a patient Project: AUTO17
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laboratory test performed an operation performed in a laboratory or at the point of care, manually or on an analyzer or with the help of a device, instrument, or system, to produce one or more observations (ie, results) Project: AUTO17 NOTE 1: The observations can be obtained by measurement of a quantity on an in vitro specimen, a finding on the specimen, calculation from other observations and data, or any other means of analysis, including the reanalysis of previously acquired data. NOTE 2: A test result is an observation.
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laboratory test result value measurement of a single variable or a single value derived logically or algebraically from other measured or derived values; the result value may be quantitative (numeric measure) or qualitative (descriptive) Project: AUTO17 NOTE: A test result is an observation.
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Laboratory Testing Workflow Profile covers the workflow related to tests performed by a medical laboratory inside a health care institution, for both identified orders and unknown orders, related to both identified patients and unidentified or misidentified patients Project: AUTO16
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laboratory worker employee who draws blood and/or performs diagnostic or other screening procedures on blood or other potentially infectious material NOTE: This includes healthcare workers who perform point-of-care testing in areas outside the laboratory.
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laboratory worker laboratory employee who draws blood and/or performs diagnostic or other test procedures on patient specimens Project: M29 NOTE: This includes health care workers who perform point-of-care testing in areas outside of the laboratory.
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laboratory-developed assay (test) an in vitro diagnostic that is a laboratory-developed test using separately purchased reagents that are not assembled in a kit and are without instructions for use from the manufacturer of the reagents Project: I/LA28 NOTE: The analytical and clinical performance characteristics of the finished assay are the responsibility of the director of the laboratory. This term is preferred to in-house developed assay or homebrew assay.
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laboratory-developed test a test developed by a laboratory for which the laboratory takes responsibility for the performance and quality control and the appropriate validation of any claims made Project: I/LA20
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laboratory-developed test also referred to as homebrew, diagnostic test that is developed by a medical laboratory under its quality management system Project: MM19 NOTE: This test is developed by the laboratory for use only in that laboratory.
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laboratory-developed test assay that is researched, developed, prepared, and validated within the laboratory institution that employs it for patient testing (eg, “in-house developed,” “user-developed”) Project: MM06, MM22 NOTE 1: Includes tests that are developed in the laboratory with measurands obtained from a single source or multiple sources and validated for clinical use; NOTE 2: Also known as “laboratory-developed procedure.”
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laboratory-developed test a test that is not approved/cleared by relevant regulatory organizations, either because the laboratory has created the assay, has substantially modified an approved/cleared assay, or is using an approved/cleared assay for a nonapproved or cleared purpose Project: M58
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laboratory-developed test a class of in vitro diagnostic devices that are manufactured (including being developed, validated, and offered) within a single laboratory Project: H60 NOTE: Laboratories opting to undertake a laboratory-developed test should consult appropriate accrediting regulations for guidance on use and verification of the performance of a laboratory-developed test.
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laboratory-developed test test or laboratory product that is independently developed, evaluated, and validated by an individual laboratory Project: MM26 NOTE 1: The test is used solely by the laboratory for validating the test without distribution to another laboratory; NOTE 2: A laboratory-developed test is distinguished from in vitro diagnostic products or approved test kits, which undergo regulatory review for a specific test indication.
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laboratory-developed test a type of test method that is designed, manufactured, and implemented for use within a single institution Alternate Term: laboratory-developed test method Project: EP19, EP35, EP32, EP45 NOTE 1: Regulatory agencies can consider modified regulatory-cleared and -approved commercial test methods laboratory-developed tests; NOTE 2: Some regulatory agencies consider measurement procedures that are partially developed by a third party (outside of a laboratory), or if used for patient testing by another laboratory, to be commercial measurement procedures, not laboratory-developed tests.
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laboratory-developed test a type of measurement procedure that is designed, manufactured, and used within a single laboratory Project: MM09 NOTE 1: Some regulatory agencies also consider modified commercial measurement procedures to be laboratory-developed tests; NOTE 2: Some regulatory agencies consider measurement procedures that are partially developed by a third party (outside the laboratory) or that are used for patient testing by another laboratory to be commercial measurement procedures, not laboratory-developed tests.
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Lambert-Beer’s Law the absorbance of a homogeneous sample containing an absorbing substance is directly proportional to the concentration of the absorbing substance and to the thickness of the sample in the optical path Project: NRSCL08, H15 NOTE: Strictly speaking, this law is applicable to true monochromatic light only.
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lamellar body densely packed layers of phospholipid synthesized and secreted by type II alveolar cells that represents a storage form of pulmonary surfactant Project: C58
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lancet (lancing device) sharp, needle-like device used to puncture skin to obtain blood (eg, from finger or heel). The device may have a spring or compression-enabled component intended to facilitate the penetration of skin Project: POCT04, POCT13
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lancing device a needle holder/instrument equipped with a lancet for obtaining capillary blood specimens. These devices can be intended for single- or multiple-use purposes in an individual or even for multiple patients. The intended use must be specified in the instructions for use Project: POCT13 NOTE: If lancing devices are intended for multiple uses in either an individual or multiple patients, the operator should refer to the instructions for use regarding requirements for proper disinfection between uses.
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latent error error due to underlying structural factors not under control of the front end operator (ISO/TS 22367) Project: ISO/PDTR 22367 EXAMPLE: Faulty equipment, poor design, management decision, or organization structure (ISO/TS 22367).
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latent error less apparent failures of organization or design that contributed to the occurrence of errors or allowed them to cause harm to patients
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lateral denoting a position farther from the median plane or midline of the body or of a structure (Dorland's Illustrated Medical Dictionary. 33rd ed. Elsevier, Inc.; 2019) Project: PRE02
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lateral flow a type of test usually involving antibody-antigen detection (immunoassay) by migration along a test strip Project: POCT15 NOTE: Also referred to as an “immunochromatographic test method.”
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lateral flow a type of antibody-based test (“immunoassay”) frequently used at the point of care Project: POCT08
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Latin 1 a specific, eight-bit, character encoding system, also known as ISO 8859, code page1252, or Western European Project: AUTO01, AUTO02, AUTO03, AUTO12
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launch a phase in the Implementation Stage of the Test Life Phases Model. The first day patient samples are tested and results are reported for health care or other purposes using a test method verified by the end user Project: EP19
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lavage the therapeutic washing out of an organ or part Project: MM17
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lay person individual without formal training in a relevant field or discipline (ISO 15197, ISO 17593) Alternate Term: lay user Project: ISO 15197, ISO CD 18113-1, ISO CD 18113-2, ISO CD 18113-3, ISO 17593 NOTE 1: Adapted from the definition of “lay user” in EN 376:2002 (ISO 15197); NOTE 2: For the purposes of ISO 15197, a user of a blood-glucose monitoring device who does not have specific medical, scientific, or technical knowledge related to blood-glucose monitoring; NOTE 3: For the purposes of ISO 17593, a lay person is a user of an oral-anticoagulation monitoring device who does not have specific medical, scientific or technical knowledge related to oral-anticoagulation monitoring; EXAMPLE: Person who performs self-testing without having a medical education.
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LDL cholesterol cholesterol bound to a low-density lipoprotein
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leader sequence See 5´ untranslated region
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leakage the loss of a seal between the container and its closure resulting in materials moving into or out of the container Project: M40
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Lean manufacturing initiative focused on eliminating all waste in manufacturing practices, principles of which include zero waiting time, zero inventory, scheduling, reduced batch sizes, and reduced process time, among others
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least significant change the minimum difference between two successive results in an individual that can be considered to reflect a real physiological change Project: C48
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least squares analysis the method of estimating parameters of a function Y = f(x) by minimizing the sum of the squares of the distances to the line in the y-direction from each data point Alternate Term: least squares estimation Project: NRSCL08
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least squares regression the method of statistically placing the location of the estimated line or curve among the data so that the sum of the squares of the distances of each data point from the line in the perpendicular direction from the x-axis (ie, parallel to the y-axis) is minimized Project: EP09, EP14 NOTE: It allows the direct algebraic computation of the coefficients and an estimate of their uncertainty.
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least squares regression analysis 1) the method of statistically placing the location of the estimated line or curve among the data so the sum of the squares of the distances of each data point from the line in the perpendicular direction from the x-axis (ie, parallel to the y-axis) is minimized; 2) the process of estimating the parameters of a model by optimizing the value of an objective function and then testing the resulting predictions for statistical significance against an appropriate null hypothesis model; 3) the process of mathematically describing the relationship between two or more variables Project: QMS24 NOTE 1: It allows the direct algebraic computation of the coefficients and an estimate of their uncertainty; NOTE 2: This can include the parametric testing of the statistical significance of the relationship, if random errors are assumed to be normal.
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LECIS acronym for Laboratory Equipment Control Interface Specification Project: AUTO01, AUTO02, AUTO03
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lectin protein of nonimmunogenic origin with two or more binding sites that recognize and bind to specific saccharide residues (ISO 19001) Project: ISO 19001
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left shift when the fluorescence seen with the test sample is less than that seen with the negative control Project: ILA29
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legacy bar code a linear (one-dimensional) or two-dimensional bar code that does not satisfy either the requirements of CLSI AUTO14 or the requirements of the ISBT 128 standard Project: AUTO14
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lethal an instrument of death, such as a toxin, organism, or weapon
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leukemia a type of malignant neoplasm (“cancer”) that predominantly affects circulating blood cells and the bone marrow Project: MM02
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leukocyte differential count determining the proportion or absolute concentration of defined classes or subsets of white blood cells in a sample of blood Project: H20 NOTE: In CLSI document H20, all counts are given in proportional terms.
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Levey-Jennings chart a graph that identifies the mean, the working range, and other limits for a control sample and shows results of control tests over a period of time Alternate Term: Levey-Jennings-Sherhart chart Project: NRSCL08
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library (genomic) a collection of DNA fragments, generated from a genome or other DNA source of interest, that serves as the substrate for amplification and subsequent next-generation sequencing Project: MM09 NOTE 1: A collection of clones that is made from a set of randomly generated overlapping DNA fragments and that represents the entire genome of an organism; NOTE 2: Also known as a “clone bank.”
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licensure process by which a laboratory is recognized as qualified by a competent authority to provide specified services Project: QMS05
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life-cycle all phases in the life of a medical device, from the initial conception to final decommissioning and disposal (ISO/DIS 14971) Project: ISO/DIS 14971
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ligand an entity that binds to a receptor Project: NRSCL08 NOTE 1: For example, an atom, ion, molecule, antibody, hormone, or drug; NOTE 2: In immunological testing, the terms "ligand" and "analyte" are frequently used synonymously.
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ligand an entity that binds to its receptor Project: I/LA28 NOTE 1: For example, an antigen, or a hormone, or drug; NOTE 2: In immunological testing, the terms “ligand” and “analyte” are frequently used synonymously, because they are often targets of the immunoassay.
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ligation the linkage of two fragments of DNA by forming a phosphodiester bond Project: MM17
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light polypeptide chain a polypeptide of molecular mass of about 25 000 Daltons Project: NRSCL08 NOTE 1: A pair of light chains linked to two heavy chains forms the immunoglobulin molecule; NOTE 2: The light chains of type K and type L immunoglobulins are known respectively as kappa and lambda chains.
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light scatter the phenomenon of multidirectional reflection exhibited by radiant energy (eg, visible light) when encountering a reflective surface Project: NRSCL08 NOTE: In flow cytometry, a measurement of the extent of radiant energy scatter in different directions is used to characterize the size, shape, and other characteristics of the reflective body.
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light transmission aggregometry an in vitro assay that measures the change in light transmission of stirred platelet-rich plasma after the addition of a platelet agonist Alternate Term: LTA Project: H58
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Lightweight Directory Access Protocol a client-server protocol that supports basic use of the X.500 Directory (or other directory servers) without incurring the resource requirements of the full Directory Access Protocol (RFC 2828; RFC 1777) Project: AUTO09
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Lightweight Directory Access Protocol a software protocol for enabling anyone to locate organizations, individuals, and other resources such as files and devices in a network, whether on the public Internet or on a corporate intranet Project: QMS22 NOTE: Lightweight Directory Access Protocol is also referred to as Active Directory.
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likelihood ratio (LR) the ratio of the likelihood that a given test result would be expected in a patient with the target disorder compared to the likelihood that the same result would be expected in a patient without the target disorder
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likelihood ratio for a population of screened individuals, this is the detection rate divided by the false-positive rate. It is the number of times individuals with positive results are more likely to have the disorder for which they are being tested than individuals who have not been tested Project: I/LA25 NOTE: This should not be confused with the likelihood ratio applicable to individuals, which is the ratio of the heights of the relative frequency distributions in affected and unaffected individuals at the value of the test result. It is the number of times an individual with that value is more likely to have the disorder for which he or she is being tested than individuals who have not been tested.
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limit (allowable total error) practical performance characteristic for allowable total error that should be achievable by currently available testing technology Project: EP46 NOTE 1: Test systems that can meet current allowable total error limits may not necessarily meet optimal goals for patient testing; NOTE 2: Test systems that do not meet current allowable total error limits may not be suitable for patient testing without further investigation.
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limit of blank highest measurement result that is likely to be observed, with a stated probability (α), for a blank sample Alternate Term: In Europe, critical value (ISO 11853) Project: EP17, EP12, MM17, H26, MM06, MM09, C62, MM24, EP39 NOTE 1: Limit of blank is not an actual concentration from which measurements are obtained; the actual concentration at which a positive signal is ensured is called the “limit of detection.” Similarly, limit of blank is the lowest value expected from a sample that contains a level of the measurand equal to the limit of detection with stated probability; NOTE 2: Also called “critical value” (ISO 11843); NOTE 3: The term “critical value” is used in ISO 11843 as the highest result that can reasonably be expected from a blank sample (a sample with concentration at or near zero). It is the instrument (method) response, above which the sample can be considered to have a positive value of the measurand. However, this term is commonly used in medical laboratories for test results that indicate an important medical condition. Therefore, in EP17, this response threshold is called the “limit of blank”; NOTE 4: Limit of blank is the same as the “lower limit of determination,” the lowest result obtained by a stated measurement procedure that can be given with a statement of uncertainty of measurement; NOTE 5: Limit of blank is also called “critical value of the net state variable” (ISO 11843-1); NOTE 6: Typically, ≥ 95% of all observed results on blank samples have concentration measurements less than the limit of blank when tested under routine medical laboratory conditions and in a defined type of sample.
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limit of blank the highest measurement result that is likely to be observed (with a stated probability [alpha]) for a blank reaction Project: MM22 NOTE: Limit of blank is not an actual concentration from which measurements are obtained; the actual concentration at which a positive signal is ensured is called the limit of detection. Limit of blank is the highest apparent analyte concentration expected to be found when replicates of a blank reaction (containing no analyte) are tested.
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limit of detection in molecular methods and quantitative molecular methods, the lowest concentration of measurand that can be consistently detected (typically, in ≥ 95% of samples tested under routine clinical laboratory conditions) and in a defined type of sample Project: MM06 NOTE: This concentration must yield an assay value that can be reproducibly distinguished from values obtained with samples that do not contain the measurand.
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limit of detection lowest amount of measurand (analyte) in a sample that can be detected but not quantified as an exact value Alternate Term: detection limit Project: I/LA23, MM10, I/LA21, POCT07, MM19, MM22 NOTE 1: In molecular methods and quantitative molecular methods, the lowest concentration of measurand (analyte) that can be consistently detected (typically, in greater than or equal to 95% of samples tested under routine clinical laboratory conditions) and in a defined type of sample; NOTE 2: This concentration must yield an assay value that can be reproducibly distinguished from values obtained with samples that do not contain the measurand (analyte).
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limit of detection the lowest amount of measurand that can be detected with 95% confidence, but not quantified as an exact value (WHO-BS/95.1793) Project: MM14
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limit of detection measured quantity value, obtained by a given measurement procedure, for which the probability of falsely claiming the absence of a measurand in a material is β, given a probability α of falsely claiming its presence (modified from JCGM 200:2012) Project: EP17, C62, MM23, M67 NOTE 1: In quantitative and qualitative molecular measurement procedures, the lowest concentration of analyte that can be consistently detected (typically, in ≥ 95% of samples tested under routine medical laboratory conditions and in a defined type of sample); NOTE 2: Also called “lower limit of detection,” “minimum detectable concentration” (or value), and “detection limit” and formally referred to as the “minimum detectable value of the net state variable.”
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limit of detection the lowest quantity of a nucleic acid that can be sequenced reliably and distinguished from its absence, typically within a stated confidence limit Project: MM09 NOTE 1: In qualitative and quantitative molecular methods, the lowest concentration of measurand that can be consistently detected (typically, in ≥ 95% of samples tested under routine medical laboratory conditions) in a defined type of sample. This concentration must yield an assay value that can be reproducibly distinguished from values obtained for samples that do not contain the measurand; NOTE 2: For somatic applications, “limit of detection” refers to the minimum allele fraction that can be detected if the adequate amount of tumor cells (ie, neoplastic cell content) is present.
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limit of quantification in quantitative molecular methods, the lowest and highest concentrations of measurand that can be detected with acceptable precision and trueness, under routine clinical laboratory conditions, in a defined type of sample Project: MM06 NOTE 1: Acceptable precision and trueness depend on technological limitations and on the clinical use for the assay; NOTE 2: These concentrations establish the measuring range for the assay.
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limit of quantification lowest amount of measurand in a sample that can be quantitatively determined with stated acceptable precision and stated acceptable accuracy, under stated experimental conditions Project: MM14, MM17 NOTE: In disciplines other than molecular methods, the terms "limit of quantitation" or "lower limit of quantitation" are used instead.
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limit of quantitation lowest amount of a measurand in a material that can be quantitatively determined with stated accuracy (as total error or as independent requirements for bias and precision), under stated experimental conditions Project: EP17, C57
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limitation of the procedure specific situation in which an IVD examination procedure might not perform as intended (ISO 18113-1)
Project: ISO 18113-1 NOTE 1: Factors that affect the performance of an IVD examination procedure can be physiological as well as analytical (ISO 18113-1); NOTE 2: Adapted from FDA, Labelling Requirements — In Vitro Diagnostic Devices. Guidance on applicability of 21 CFR 809.10(b), Labelling Requirements for Inserts and Outer Packaging, available at http://www.fda.gov/cdrh/devadvice/332.html, 21 July 2000 (ISO 18113-1).
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limiting conditions extreme conditions that a measuring instrument is required to withstand without damage, and without degradation of specified metrological characteristics when it is subsequently operated under its rated operating conditions (VIM93) NOTE 1: The limiting conditions for storage, transport, and operation may be different; NOTE 2:The limiting conditions may include limiting values of the measurand and of the influence quantities.
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limiting operating condition extreme operating condition that a measuring instrument or measuring system is required to withstand without damage, and without degradationof specified metrological properties, when it is subsequently operated under its rated operating conditions (JCGM 200:2008) Project: ISO IEC Guide 99 NOTE 1: Limiting conditions for storage, transport or operation can differ (JCGM 200:2012); NOTE 2: Limiting conditions can include limiting values of a quantity being measured and of any influence quantity (JCGM 200:2012).
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limits of erroneous results zone region on an error grid plot corresponding to measurement errors that are regarded as likely to cause patient harm Project: EP27
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line listing of antimicrobial susceptibility test data a summary of antimicrobial susceptibility test results for individual isolates with each line containing susceptibility results for all agents tested against the isolate together with other pertinent information (eg, patient hospital number, organism, isolate source, specimen collection date) for that isolate Project: M39
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lineage in bacterial strain typing, a set of isolates that are derived from a common ancestor and are thereby related Project: MM24 NOTE: Isolates that are distantly derived might show some genetic divergence; isolates that are recently derived would be expected to be closely genetically related and thus to have a common genotype by a variety of typing methods (ie, to represent a strain).
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lineage infidelity the coexpression of markers of different cell lineages by a cell or cell population, ie, a T-cell lymphoid neoplasm, by immunophenotype, that harbors a B-cell gene rearrangement
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linear of or pertaining to lines Project: NRSCL08
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linear amplification a linear amplifier (amp) produces a signal output directly proportional to the input signal amplitude Project: H42, H43 NOTE: For example, a linear amp could have output varying from 1 to 5 V as the input signal varies from 0.01 to 0.05 V.
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linear amplification the delivery of output that is directly proportional to the input
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linear amplifier produces a signal output proportional to the input signal amplitude Project: H52 NOTE: For example, a linear amplifier could have output varying from 1 to 5 V as the input signal varies from 0.01 to 0.05 V.
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linear drift a change in measurement value that is directly proportional to duration Project: EP10
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linear equation an equation that represents a straight line Project: EP06 NOTE 1: A linear equation is typically represented mathematically by Y = AX + B, using the common convention that X is represented by the horizontal axis and Y is represented by the vertical axis, A is the slope, and B is the y-intercept; NOTE 2: To preserve proportionality, the y-intercept equals 0.
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linear range the range over which the testing systems results are acceptably linear; that is, where nonlinear error is less than the error criterion Project: MM06
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linear regression a statistical calculation that results in parameters that describe the assumed linear relationship between values of an independent and a dependent variable wherein the independent variable is known exactly NOTE: The calculation is based on the mathematical definition of a line (Y = a + bX); and the mathematical minimization of the vertical distance between each data point and the regression line.
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linear scale scale in which each scale spacing is related to the corresponding scale interval by a coefficient of proportionality that is constant throughout the scale (VIM93) NOTE: A linear scale having constant scale intervals is called a regular scale.
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linearity assuming no constant bias, the ability (within a given range) to provide results that are directly proportional to the concentration {amount} of the measurand in the test sample Project: H26 NOTE: Hematology analyzers function primarily as particle counters (white blood cell concentration, red blood cell concentration, platelet concentration). Linearity is a chemistry concept in relation to spectrophotometric absorbance/transmission and measurand concentration. Technically, only the hemoglobin measurement on a hematology instrument is such a chemistry test. Although commercial “linearity kits” exist, the materials therein (particles, matrix) often differ significantly from fresh whole blood; thus, results may not correctly reflect instrument performance with fresh blood. Approaches involving concentration/dilution of fresh blood cells are preferred to assess analytical measuring interval recovery.
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linearity ability (within a given interval or range) to provide results that are directly proportional to the concentration (or amount) of the analyte (measurand) in the test sample Project: EP06, EP10, H44, I/LA24, MM14, MM01, MM16, POCT09, I/LA20, EP39, H62 NOTE 1: Linearity typically refers to the overall system response (ie, the final analytical answer rather than the raw instrument signal); NOTE 2: The linearity of a system is measured by testing levels of a measurand that are known by formulation or known relative to each other (not necessarily known absolutely); when the system results are plotted against these values, the degree to which the plotted data conform to a straight line is a measure of system linearity; NOTE 3: Linearity typically refers to the overall system response rather than the raw instrument output, but in I/LA20, the definition applies to both and is considered especially pertinent to instrument output. See “parallelism.” It can be defined by evaluating the slope of a dose-response curve on a semilog plot over a defined working range; NOTE 4: Linearity tests are conducted over the system’s analytical measurement range to validate the system’s overall response to varying levels of the analyte (measurand) in question; NOTE 5: Competition or agglutination inhibition assays may be linear, but are inversely proportional, rather than directly proportional, to the concentration of analyte in the sample; NOTE 6: For some applications, users may choose to verify linearity using a linear equation that includes a term for the y-intercept. In this less restrictive case, linearity is the ability of a testing system to provide results that conform to a straight line of the form Y = AX + B within a given interval. Additional information (eg, from a comparison study or calibration verification) should be provided to check whether the term for the y-intercept is close to zero.
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linearity (of a measuring system) ability to provide measured quantity values that are directly proportional to the value of the measurand in the sample Project: EP17, C62, C63
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linearity interval the interval over which measurement results adequately conform to a fitted straight line Project: EP06 NOTE 1: The fitted line might or might not include a term for the y-intercept; NOTE 2: The range from the lower limit of the linearity interval (LLLI) to the upper limit of the linearity interval (ULLI) is denoted as [LLLI, ULLI].
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line-probe assay a family of novel DNA strip-based tests that use nucleic acid amplification techniques and reverse hybridization methods for the rapid detection of specific nucleic acid sequences Project: MM24
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link service access point See service access point Project: POCT01
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linkage analysis the assessment of genetic disease or carrier risk by observation of the cosegregation of the disease phenotype with one or more polymorphic DNA markers Project: MM12, MM01 NOTE: Most often used as the polymorphic markers are restriction fragment length polymorphisms and variable number of tandem repeats and/or short tandem repeats.
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linkage disequilibrium the occurrence of specific combinations of alleles in coupling phase at two or more linked loci more frequently than expected by chance Project: MM19
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linkage mapping a determination for a species or experimental population that shows the position of its known genes or genetic markers relative to each other in terms of recombination frequency, rather than a specific physical distance along each chromosome Project: MM24
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lipemia a condition in which lipid levels in the blood are sufficiently elevated to cause the sample to appear milky or turbid Project: C29, C32, C37, C56 NOTE: This can produce erroneous results for some tests as a result of direct physicochemical interference or by causing changes in the plasma water fraction.
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lipemia a condition in which too much fat or too many lipids are in the blood Project: POCT04 NOTE: A lipemic sample looks milky and turbid, and it can produce erroneous results.
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lipoprotein any of the class of proteins that contain a water-insoluble lipid combined with a simple protein; the combination that allows their dissolution in plasma
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liquid biopsy a test to indirectly assess the genomic profile of a tumor using only blood (or a body fluid sample) rather than a tissue biopsy Project: MM26 NOTE 1: Substrate for analysis is typically circulating tumor or cell-free nucleic acid; NOTE 2: Test can be used for diagnosis if a suitable tissue biopsy is not available or in posttreatment monitoring or screening scenarios
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liquid chromatography an analytical chromatographic technique that is useful for separating molecules based on partition coefficients between a liquid and a stationary phase Project: C63
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liquid chromatography pump pump used to deliver mobile phase to the autosampler and mass spectrometer Project: NBS04, NBS09
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liquid-based Pap preparations a method of slide preparation where a sample of cells from the cervix/vagina is collected and rinsed into a vial of preservative fluid in the patient examination room, then transported to the laboratory where an automated processing device produces a thin layer of evenly distributed cervicovaginal cells onto a glass slide Project: GP15
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liquid-liquid junction the interface between two dissimilar solutions that typically serves as the point of connection between an indicator and reference half-cell Project: C39
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list mode a data storage format in which individual values of all parameters for each cell in a sample are retained, allowing maximum flexibility for subsequent analysis Project: H42, H43
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listmode data storage format in which individual values of all parameters for each cell in a sample are retained, allowing maximum flexibility for subsequent analysis Project: H52
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lithium heparin the commercially prepared lithium salt of heparin Project: NRSCL08
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lithium heparin a manufactured lithium salt of heparin Project: NRSCL08 See heparin.
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live gate also called an acquisition gate or enrichment gating, this represents a set of parameters used to collect data on a population of cells for further analysis Project: H42, H43 NOTE: A live gate is typically set when the population of interest represents only a minor fraction of the total population, but when one or more parameters clearly distinguishes this population from the larger population of less important cells.
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local codes designations used for laboratory data created within the health care enterprises’ various electronic data systems, including in vitro diagnostic devices Project: AUTO17
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local emergency operations plan plan outlining emergency response guidelines for the relevant agencies and entities that can provide a robust response to any emergency Project: GP36 NOTE 1: Response plans are integrated and identified by jurisdictional authority; eg, State Emergency Operations Plan; NOTE 2: The local emergency operations plan may be available online via the local government’s website.
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local emergency planning committee committee that seeks to understand and control chemical hazards in the community and develop local response plans in case of accidental release Project: GP36 NOTE 1: Local emergency planning committees operate under the US Environmental Protection Agency; NOTE 2: Local emergency planning committees are organized nationally by county or parish.
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local test system ISI calibration determination of local test system International Sensitivity Index using certified plasmas Project: H54
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location a physical place within the laboratory, with a unique identifier (eg, refrigerator shelf number, instrument buffer ID, track identifier) Project: AUTO01, AUTO07, AUTO02
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locus 1) the position of a gene on a chromosome; 2) the position on a chromosome of a DNA sequence that is not necessarily contained within a gene Project: MM10, MM12, MM01, MM22, MM24 NOTE 1: Different forms (alleles) of the gene may occupy the locus; NOTE 2: The position on a chromosome of a DNA sequence that is not necessarily contained within a gene.
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log book a document containing information in physical or electronic form Project: POCT12
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logarithmic amplification amplification with a response that is logarithmic rather than direct
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logarithmic amplification a logarithmic amplifier (log amp) produces an output signal value proportional to the logarithm of the input signal value Project: H42, H43 NOTE: A four-decade log amp might, for example, have an output of 0 V for a 1-mV input; 2.5 V for a 10-mV input; 5 V for a 100-mV input; 7.5 V for a 1-V input; and 10 V for a 10-V input. Log amps are useful when analyzing samples containing cells whose measured parameters differ by orders of magnitude.
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Logical Observation Identifiers Names and Codes a common language (set of identifiers, names, and codes) for identifying health measurements, observations, and documents Project: AUTO16
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Logical Observations Identifiers Names and Codes a systematic approach to formal names and codes for laboratory results and clinical variables with numeric, coded, or narrative text values developed by a consortium of laboratories, system vendors, hospitals, and academic institutions Alternate Term: LOINC Project: AUTO01, AUTO02, AUTO03
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logit a mathematical transformation function for ratio or percentage values in cumulative logistic distribution probability units Project: EP17
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LOINC acronym for Logical Observations Identifiers Names and Codes (refer to website, http://www.regenstrief.org/loinc/loinc.htm) Project: AUTO01, AUTO02, AUTO03
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longstanding HIV infection the phase of infection after complete maturation of an antibody response typically beginning six to 12 months after seroconversion Project: M53 NOTE: Sometimes referred to as an established infection.
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long-term care facility a facility that provides rehabilitative, restorative, and/or ongoing skilled nursing care to patients or residents in need of assistance with activities of daily living such as nursing homes, skilled nursing facilities, and assisted living facilities Project: M39
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long-term follow-up ongoing steps taken after diagnosis to prevent morbidity and mortality in affected individuals Project: NBS02, NBS09, NBS03, NBS05, NBS08, NBS10 Source: Newborn Screening Glossary NOTE 1: In the context of public health, long-term follow-up most often involves periodic assessments of health outcomes as part of system evaluation. Other activities might include but are not limited to care coordination and assurance of access to treatments and/or other interventions; NOTE 2: See short-term follow-up and intervention.
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loss of heterozygosity implies a previous state of heterozygosity that, by a somatic mechanism (eg, deletion, mitotic recombination), was converted to a single genotype Project: MM21
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lost to follow-up (for newborn screening) status assigned to an individual for whom the newborn screening program has no record of completion of recommended follow-up testing and/or evaluation Project: NBS03, NBS02 Source: Newborn Screening Glossary NOTE 1: This status might be assigned at a defined end point, even when all prescribed follow-up protocols have been completed; NOTE 2: Newborn screening programs might choose to further delineate this status (eg, unacceptable specimens vs screen-positive results) to better assess gaps in follow-up.
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lot one or more components or finished devices that consist of a single type, model, class, size, composition, or software version that are manufactured under essentially the same conditions and that are intended to have uniform characteristics and quality within specified limits (ISO 15197) Alternate Term: batch Project: ISO 15197, I/LA28 NOTE: In Directive 98/79/EC and in European Standards, the term “batch” is preferred.
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lot See batch
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lot batch one or more components or finished devices that consist of a simple type, model, class, size, composition, or software version that are manufactured under essentially the same conditions and that are intended to have uniform characteristics and quality within specified limits (ISO 15198) Project: ISO 15198
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lot number See batch code
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lot number an alphanumeric and/or symbolic identification placed on the label by the manufacturer that enables traceability to the manufacturing history of the product Alternate Term: control number Project: GP39
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low birth weight a birth weight of < 2500 g Project: NBS03, NBS10 Source: Newborn Screening Glossary NOTE 1: In NBS03, references to low birth weight include very low birth weight and extremely low birth weight, unless otherwise noted; NOTE 2: See very low birth weight and extremely low birth weight.
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lower end of the measuring range See limit of quantitation
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lower limit of detection lowest amount of analyte (measurand) in a sample that can be detected with (stated) probability, although perhaps not quantified as an exact value Alternate Term: minimum detectable concentration; minimum detectable dose; minimum detectable value; detection limit; lower limit of detection Project: MM03, MM16, C52, C50, I/LA21, I/LA33, C43, H26, NBS06, MM07, I/LA20, POCT15, H62 NOTE 1: In many clinical laboratories and diagnostic applications, “sensitivity” or “analytical sensitivity” are used interchangeably with “limit of detection,” “lower limit of detection,” or “detection limit.” However, “sensitivity” is also used in several other ways, some of which are preferred uses in their areas. In different applications, “sensitivity” might be used alone or with modifiers: The most common use is consistent with the International Union of Pure and Applied Chemistry definition of “analytical sensitivity,” which is “the slope of the calibration curve.” The calibration function relates the mean of the measured concentrations to the actual (known) concentrations; the steeper the slope of the calibration curve, the more sensitive the assay is to slight changes in amount of analyte. This is not the same as the limit of detection. Indeed, even if the slope of the calibration curve is steep, the lowest concentration that can be reliably detected can be large if there is a high variation of the measured signal. On the other hand, a method with a moderate analytical sensitivity (moderate slope of the calibration curve) and very low random variation of the signal can have a low limit of detection; NOTE 2: The lowest concentration of analyte that can be consistently detected (typically, in ≥ 95% of samples tested under routine clinical laboratory conditions) and in a defined type of sample. This concentration must yield an assay value that can be reproducibly distinguished from values obtained with samples that do not contain the analyte; NOTE 3: Sometimes used to indicate sensitivity; NOTE 4: Detection limit is the smallest quantity of an analyte that can be reproducibly and statistically distinguished from the background (including variation in background), or a zero calibrator in a given assay system; NOTE 5: It is usually defined at the 95% confidence interval and has also been called the lower detection limit or positive threshold of the assay; this term is not synonymous with analytical sensitivity; NOTE 6: Assuming an adequate number of samples and that their distributions are similar, an equivalent distribution between the 0 calibrator and low positives, the 95% confidence interval means 3.3 standard deviations between the mean levels produced by the 0 calibrator and the low positives. The positive cutoff level should, therefore, be greater than 3.3 standard deviations from the mean of the 0 calibrator; NOTE 7: For immunohematological tests, no authoritative calibration scale exists to determine a quantitative limit; NOTE 8: Grading of reaction strength is an integral part of most immunohematology testing. Although many variables can affect the strength of a reaction (eg, antibody level, immunoglobulin class, antigen expression, methodologies), when a sample is repeatedly weakly reactive, it can estimate the lowest level at which an antibody or antigen is detectable by the method or system under evaluation; NOTE 9: For gas chromatography/mass spectrometry or gas chromatography/tandem mass spectrometry confirmation analysis, the compound must also satisfy identification criteria in order to be deemed detected; NOTE 10: Also called “lower limit of detection,” or “minimum detectable concentration” (or dose or value), and sometimes used to indicate “analytical sensitivity”; NOTE 11: In FISH analysis, there is no true “blank,” so it is usually not possible to incorporate dispersion of the measurement method into a statistical calculation of the limit of detection.
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lower limit of detection measured quantity value, obtained by a given measurement procedure, for which the probability of falsely claiming the absence of a component in a material is β, given a probability α of falsely claiming its presence (JCGM 200:2012); lowest amount of analyte (measurand) in a sample that can be detected with (stated) probability, although perhaps not quantified as an exact value Alternate Term: limit of detection; detection limit Project: C63
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lower limit of detection measured quantity value, obtained by a given measurement procedure, for which the probability of falsely claiming the absence of a measurand in a material is β, given a probability α of falsely claiming its presence (modified from JCGM 200:2012) Project: EP12 NOTE 1: In quantitative procedures, the lowest concentration of analyte that can be consistently detected as greater than limit of blank (typically, in ≥ 95% of samples tested under routine medical laboratory conditions and in a defined type of sample); NOTE 2: Also called “minimum detectable concentration” (or value), and “detection limit,” and formally referred to as the “minimum detectable value of the net state variable” (ISO 11843-1); NOTE 3: In an analyte-detection, qualitative examination, the lower limit of detection is determined with a hit-rate study.
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lower limit of detection lowest amount of measurand in a sample that can be detected but not quantified as an exact value Project: MM01, MM24 NOTE 1: In molecular methods and quantitative molecular methods, the lowest concentration of measurand that can be consistently detected (typically, in ≥ 95% of samples tested under routine medical laboratory conditions) and in a defined type of sample; NOTE 2: This concentration must yield an assay value that can be reproducibly distinguished from values obtained with samples that do not contain the measurand.
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lower limit of determination See limit of quantitation
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lower limit of quantitation lowest amount of measurand in a sample that can be quantifiably determined with stated acceptable precision and trueness under stated experimental conditions Alternate Term: limit of quantitation Project: H26, MM01
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lower limit of quantitation lowest concentration of analyte in a sample that can be quantitatively determined with stated acceptable precision and trueness, under stated experimental conditions Alternate Term: limit of quantitation Project: C50, C43, NBS06, C52, C63, EP39 NOTE: Also called “lower limit of determination” and “lower end of the measuring range.”
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lower limit of quantitation lowest amount of a measurand in a material that can be quantitatively determined with stated accuracy (as total error or as independent requirements for bias and precision), under stated experimental conditions Project: I/LA20, NBS09, NBS04, NBS07, H62 NOTE 1: The terms sensitivity, analytical sensitivity, functional sensitivity, lower limit of detection, minimum detectable dose, lower limit of blank, and lower limit of quantitation all have been used to describe the smallest concentration of an analyte that can be reliably measured in an analytical procedure (ie, reproducibly determined with suitable precision and accuracy and statistically different from “0” dose); NOTE 2: Intent to lower the lower limit of quantitation of an immunoglobulin E antibody assay has been used to justify the use of labile, low abundance, or missing allergen molecules, either alone or supplemented into an extract, for use in immunoglobulin E antibody detection. True quantification of allergen-specific immunoglobulin E antibody requires excess quantities of each allergenic molecule of a given specificity in the reagent. In case of labile, low abundance, or missing allergen molecules, immunoglobulin E quantities measured with allergen extracts will remain low or misleading. Data have recently been put forward demonstrating the measurement of higher quantities of allergen-specific immunoglobulin E as consequence of lowering the lower limit of quantitation of an immunoglobulin E antibody assay by using select allergen molecules as immunoglobulin E–test reagents; NOTE 3: Also called “lower limit of determination” and “lower end of the measuring range.”
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lower limit of quantitation the lowest amount of analyte in a sample that can be quantitatively determined with stated acceptable precision and stated acceptable accuracy, under stated experimental conditions Project: C34
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lower limit of quantitation the smallest amount of a substance that can be measured accurately Project: EP34
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lower limit of the linear interval lowest measurand concentration at which the measurement procedure displays a linear relationship with actual measurand content Project: EP17
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lower limit of the measuring interval the lowest measurand concentration at which all defined performance characteristics of the measurement procedure are met Project: EP17, C62, C57 NOTE: Formerly, the term “lower limit of quantitation” was used in CLSI documents.
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low-level protocol a protocol describing the electrical and mechanical connections of the physical layer of communication between systems and the software protocol definition Project: AUTO01, AUTO02, AUTO03
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low-level radioactive waste radioactive waste that is not classified as high-level, transuranic, spent fuel, or certain byproduct material Project: QMS28 NOTE 1: The waste types within the domain of nuclear power plants and fuel facilities; NOTE 2: Low-level radioactive waste is a broad and somewhat ambiguous category, defined not by what it is, but by what it is not; NOTE 3: Most generators of infectious and medical waste generate only low-level radioactive waste
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luminescence the emission of light that does not derive energy from the temperature of the emitting body, as in phosphorescence and fluorescence Project: H58 NOTE: This principle of bioluminescence is used as a measure of platelet adenosine triphosphate content using a specific luminescent substrate and enzyme system. The emission of light is proportional to the amount of adenosine triphosphate released.
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luminescence oxygen channeling immunoassay a type of chemiluminescent assay that uses two types of ligand-coated latex beads. One of the beads is a chemiluminescent bead in which an olefin is dissolved Project: H59 NOTE: The olefin can react rapidly with singlet oxygen. The reaction yields a dioxetane that spontaneously decomposes with efficient emission of light. This can be used as a homogeneous assay.
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lumophore a molecule capable of emitting a luminescent response, or light measured as photons, upon appropriate excitation Project: I/LA23
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lupus anticoagulant an immunoglobulin (immunoglobulin G, immunoglobulin M, or both) that may be observed in the plasma of otherwise healthy individuals, as well as patients with systemic lupus erythematosus, antiphospholipid syndrome, and a variety of other conditions. Lupus anticoagulants may be transitory or long lasting and interfere with in vitro phospholipid-dependent tests of coagulation (eg, prothrombin time, activated partial thromboplastin time, dilute Russell viper venom time) Project: H21, H47
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lymphoma a type of malignant neoplasm ("cancer") that predominantly affects cells in solid lymphatic tissue, such as lymph nodes Project: MM02
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lymphosum in an immunophenotyping assay for the major lymphocyte subsets (T cell, B cell, natural killer [NK] cell), the lymphosum is the sum of % CD3+ (T cells), % CD19+ (B cells), and % CD3− (CD56+ ± CD16+) (NK cells)
Project: H62 NOTE: In a medical laboratory, if the assay uses side-scatter/CD45 gating, the lymphosum target range is ideally within 95% to 105%, “minimally” 90% to 110%.
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lyophilized the characteristic describing the result of the process of vacuum-freeze-drying a liquid material to make its components more stable Project: NRSCL08 NOTE: The liquid material is usually a calibrator, control, or reagent.
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lysing agent a reagent used to remove or lyse red blood cells from a sample in order to simplify the analysis of white blood cells Project: H42, H43 NOTE: Ammonium chloride in a bicarbonate buffer is the most commonly used lysing agent, although a variety of commercial preparations are also available.
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lysis use of mechanical (eg, sonication) and/or enzymatic (eg, lysozyme) treatments, detergents, or chaotropic agents to disrupt protective cellular structures such as capsules, spores, cell walls, and membranes to release endogenous nucleic acids Project: MM03, MM18, M55, MM22 NOTE 1: Resulting lysates contain host and microbial nucleic acids that need to be stabilized to protect them from cellular nucleases that are also released during the lysis process; NOTE 2: Selected methods are chosen according to source organisms and starting material, and may combine both cell disruption and inactivation of intracellular nucleases; NOTE 3: Ideal lysis procedures must be rigorous enough to disrupt the target cell type and gentle enough to preserve target nucleic acid.
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lysis-centrifugation blood culture system a blood culture system that uses chemicals to lyse the blood cells, thereby releasing microorganisms into the fluid, followed by centrifugation to concentrate the microorganisms in the pellet Project: M47
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lysosomal storage disorders a group of approximately 50 inherited metabolic diseases that result from defects in lysosome function Project: NBS07, NBS09 NOTE: Each disease is characterized by a defect in a specific hydrolytic enzyme or other protein, intracellular accumulation of an unmetabolized substrate, clinical progression affecting multiple tissues or organs, and considerable phenotypic variation within the disease.
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lysosome a membrane-bound organelle in the cytoplasm of most cells containing various hydrolytic enzymes that function in intracellular digestion, prominent in leukocytes but not present in red blood cells Project: NBS07, NBS09
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m/z an abbreviation used to denote the quantity formed by dividing the mass of an ion by the number of charges carried by it Project: C50, C57, C64, NBS04, NBS07, C63, NBS09, NBS08 NOTE 1: It has long been called the “mass-to-charge ratio,” although according to the currently accepted International Union of Pure and Applied Chemistry definition, m is not the ionic mass, nor is z a multiple of the electronic charge, eˉ; NOTE 2: The dimensionless quantity that is the independent variable in a mass spectrum (Murray et al; IUPAC recommendations 2013. Pure Appl Chem. 2013;85(7):1515-1609).
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m/z an abbreviation used to denote the dimensionless quantity formed by dividing the mass of an ion in unified atomic mass units by its charge number (regardless of sign) Project: MM01, C43, C38, C40 NOTE 1: The symbol is written in italicized lowercase letters with no spaces; NOTE 2: The term “mass-to-charge ratio” is deprecated. “Mass-to-charge ratio” has been used for the abscissa of a mass spectrum, although the quantity measured is not the quotient of the ion’s mass to its electric charge. The three-character symbol m/z is recommended for the dimensionless quantity that is the independent variable in a mass spectrum (IUPAC 2013).
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machine learning a subset of artificial intelligence that uses neural networks to solve health care problems and predict outcomes of therapies by deploying pattern recognition in big data sets Project: MM26
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macrophage motile, phagocytic, mononuclear cell that originates in the tissues and may be confused morphologically with protozoan trophozoites (particularly those of Entamoeba histolytica) Project: M28
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macrotier represents shared electronic health records exchanged across health care providers or between a health system and other entities, such as a pharmacy or public health agency Project: AUTO17
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magnetic analyzer a momentum focusing device that produces a magnetic field perpendicular to the direction of ion travel Project: C43, C50 NOTE: The effect of the magnetic analyzer is to bring to a common focus all ions of a given momentum with the same mass to charge ratio.
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magnetron a cylindrical diode with an anode and a cathode Project: GP28 NOTE 1: Superimposed on the diode is a magnetic field that is aligned with the cathode; NOTE 2: A ring of mutually coupled resonant cavities is in the anode so a potential of several thousand volts is reached across the diode; NOTE 3: The released electrons, under the influence of the magnetic field, resonate, and the magnetron oscillates.
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maintainability the ease with which a software system or component can be modified to correct faults, improve performance or other attributes, or adapt to a changed environment (IEEE 610.12-1990) Project: AUTO08
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maintenance combination of all technical and management actions intended to retain an item in, or restore it to, a state in which it can perform as required (ISO 14224) Project: QMS23
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maintenance a phase in the Implementation Stage of the Test Life Phases Model. This phase includes all processes performed to keep a measuring system operational, including demonstration of acceptable performance using quality control, proficiency testing, and other regular activities associated with routine use Project: EP19 NOTE 1: Microbiologists often refer to this ongoing activity as “validation”; NOTE 2: Maintenance should not be confused with calibration verification (an ongoing regulatory requirement) that takes place in this phase.
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maintenance medium cell culture nutrient solution intended to maintain viability and integrity of a confluent or nearly confluent cell culture monolayer without promoting abundant mitotic division Project: M41
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major allergen generally regarded as an allergenic molecule to which > 50% of clinically allergic patients with an allergy to its source react Project: I/LA20
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major discrepancy (MD) test result by the reference method interpreted as S and an AST device result of R. Another representation of the concept: NMD × 100/NSREF where NMD is the number of tests that result in an MD; NSREF is the number of susceptible bacterial isolates as determined by the reference method (ISO 20776-1) Project: ISO 20776-2 NOTE: The overall MD is expressed as a percentage (ISO 20776-2).
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major discrepancy discrepancy in test results when a new antimicrobial susceptibility testing system is interpreted as resistant and the comparator method result (from an existing commercial antimicrobial susceptibility testing system) is susceptible Project: M52 NOTE 1: Another representation of the concept: NMD • 100/NS where NMD is the number of tests that result in a major discrepancy; NS is the number of susceptible microbial isolates as determined by the comparator device (modified from ISO 20776-2); NOTE 2: “Discrepancy” is used in this document when two systems are in disagreement, while “error” is used when the antimicrobial susceptibility testing system result does not agree with the reference method result.
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major error error when the reference method result is susceptible and the antimicrobial susceptibility testing system under evaluation is resistant. The percentage of major error should be calculated for the susceptible isolates as determined by the reference method only, as follows: % mE= NME • 100/total isolates susceptible by reference method Project: M52 NOTE: “Discrepancy” is used in this document when two systems are in disagreement, while “error” is used when the antimicrobial susceptibility testing system result does not agree with the reference method result.
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major histocompatibility complex multimer a generic term for two or more copies of a major histocompatibility complex protein physically linked together for the purpose of enhancing the avidity of the resulting complex for T-cells. Major histocompatibility complex multimer reagents are used to identify antigen-specific T-cells through physical binding to their cell surface antigen receptors (ie, T-cell receptors) Project: I/LA26 NOTE: The linkage may be covalent, eg, as in the fusion of major histocompatibility complex molecules to immunoglobulins that provide major histocompatibility complex dimers, or noncovalent, eg, as in the streptavidin-mediated oligomerization of biotinylated major histocompatibility complex proteins, which provide major histocompatibility complex tetramers. The specificity of major histocompatibility complex multimers can be altered through variation of the peptide ligand, and/or through use of different major histocompatibility complex alleles.
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major histocompatibility complex pentamer an engineered major histocompatibility complex multimer reagent consisting of five major histocompatibility complex molecules assembled through a coiled-coil domain and comprising up to five fluorescent molecules. The fluorescent molecules are typically phycoerythrin or allophycocyanine Project: I/LA26
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major histocompatibility complex tetramer an engineered major histocompatibility complex multimer reagent Project: I/LA26 NOTE 1: A specific multimer of major histocompatibility complex molecules produced by mixing site-specific, singly biotinylated major histocompatibility complex molecules together with a tetrameric biotin-binding protein such as streptavidin; NOTE 2: The major histocompatibility complex molecules used for tetramer preparation are homogenously loaded with a single peptide ligand; NOTE 3: Usually, the streptavidin molecule is prelabeled with a fluorophore such as phycoerythrin or allophycocyanin, but other fluorophores may be used; NOTE 4: The term “major histocompatibility complex tetramer” represents an idealized version of the molecules produced by this method, which may in fact contain mixtures due to the aggregation of the labeled streptavidin molecules, or variations in their specific biotin-binding activity.
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major spill spill that spreads rapidly, presents an inhalation hazard, endangers people or the environment, and/or involves personal injury or rescue and should be handled as an emergency by the department of public safety, fire department, or hazmat team Project: GP17
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malfunction failure of the product to meet its performance specifications or otherwise perform as intended Project: EP18 NOTE: Performance specifications include all claims made in the labeling of the product (21 CFR 803.3 [n]).
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malicious code a category of software that can include not only virus threats, but also other software contaminants such as trojan horses, worms, spyware, or adware Project: POCT02 NOTE 1: It is designed by the programmer to intrude in systems and may be an annoyance or even the cause of instrument interruption, business interruption, and financial loss, and may lead to a loss of a validated status and loss of confidentiality; NOTE 2: Sometimes called “malware.”
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management coordinated activities to direct and control an organization (ISO 9000) Project: QMS11, QMS01 Source: Quality Glossary NOTE 1: Management can include establishing policies and objectives and processes to achieve these objectives (ISO 9000); NOTE 2: The word “management” sometimes refers to people, ie, a person or group of people with authority and responsibility for the conduct and control of an organization (ISO 9000).
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management review periodic, formal evaluation by leadership of the status, adequacy, and effectiveness of the quality system Project: QMS11, QMS01, QMS29 Source: Quality Glossary
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mandatory recall a mandate from a regulatory authority that a manufacturer recall a device that is a risk to health Project: HS11 NOTE: This may occur in instances where a manufacturer is no longer in business.
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manifest a shipping paper required by the regulatory authority when shipping laboratory waste that identifies the type of waste, the generator, and the transporter, as well as the destination Project: GP05, QMS28
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manual MIS microbial identification system requiring the user to inoculate, incubate, and interpret results using nonautomated methods or devices Project: M50
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manual tilt-tube method a means of determining the clotting end point of an in vitro coagulation assay Project: POCT14 NOTE 1: The determination is usually performed by the visual observation of the back-and-forth movement of plasma in a test tube to which reagents have been added to stimulate coagulation; NOTE 2: The end point of the manual tilt-tube method is the appearance of a fibrin clot.
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manufacturer natural or legal person with responsibility for the design, manufacture, packaging, or labeling of a medical device, assembling a system, or adapting a medical device before it is placed on the market and/or put into service, regardless of whether these operations are carried out by that person or on that person's behalf by a third party (modified from ISO 15198) Project: ISO 14971, ISO CD 18112-1, H57, ISO 15198, H26, H59 NOTE 1: Attention is drawn to the fact that the provisions of national or regional regulations can apply to the definition of manufacturer (ISO 14971); NOTE 2: For a definition of labelling, see ISO 13485:2003; NOTE 3: Any entity that develops a clinical laboratory measurement procedure system, regardless of if it is a traditional commercial manufacturer, a laboratory that performs testing on samples referred from outside its institution, or a laboratory that only performs testing for patients within its institution; NOTE 4: Laboratories that only use commercial measurement procedure systems are not manufacturers, but laboratories that create measurement procedure systems, or that modify commercial measurement procedure systems, are manufacturers.
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manufacturer natural or legal person responsible for the design, manufacture, fabrication, assembly, packaging, or labelling of a medical device, for assembling a system, or adapting a medical device before it is placed on the market and/or put into service, regardless of whether these operations are carried out by that person or on their behalf by a third party (ISO 18113-1)
Project: ISO 18113-1, ISO 18113-2, ISO 18113-3, M52 NOTE 1: Provisions of national or regional regulations may apply to the definition of manufacturer (ISO 18113-1); NOTE 2: Manufacturer includes those who perform the functions of contract sterilization, installation, relabeling, remanufacturing, repacking, or specification development, and initial distributors of foreign entities performing these functions (ISO 18113-1); NOTE 3: A harmonized definition of “manufacturer” is being developed by the Global Harmonization Task Force (ISO 18113-1).
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manufacturer natural or legal person with responsibility for the design, manufacture, packaging, or labelling of a medical device, assembling a system, or adapting a medical device before it is placed on the market or put into service, regardless of whether these operations are carried out by that person or on that person's behalf by a third party (ISO 14971) Project: H48 NOTE 1: Provisions of national or regional regulations may apply to the definition of manufacturer (ISO 18113-1); NOTE 2: For a definition of labelling, see ISO 13485.
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manufacturer’s selected measurement procedure measurement procedure that is calibrated by one or more primary or secondary calibrators and validated for its intended use (ISO 15197) Project: ISO 15197, ISO/DIS 17593 NOTE: ISO 17511, Figure 1 shows the manufacturer’s selected measurement procedure in the traceability chain (ISO 15197).
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manufacturer’s selected measurement procedure measurement procedure that is calibrated by one or more primary or secondary calibrators and validated for its intended use (ISO 15197) Project: ISO 17593 NOTE: ISO 17511, Figure 1 shows the manufacturer's selected measurement procedure in the traceability chain (ISO 15197).
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manufacturer’s selected measurement procedure highest level measurement procedure within the manufacturer’s operation unless the manufacturer maintains its own reference measurement laboratory Project: EP32 NOTE: Generally used to transfer a value to the manufacturer’s working calibrator.
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manufacturer’s standard See standard reference reagent Project: H54
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manufacturer’s standing measurement procedure measurement procedure that is calibrated by one or more of the manufacturer’s working calibrators or higher-order calibrators and validated for its intended use (ISO 15197) Project: ISO 15197, ISO 17593, EP32 NOTE 1: ISO 17511 shows the manufacturer’s standing measurement procedure in the traceability chain (ISO 15197, ISO 17593); NOTE 2: The standing measurement procedure is typically calibrated with the manufacturer’s working calibrator and used to transfer a value to the end-user in vitro diagnostic medical device calibrators.
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manufacturer’s working calibrator the standard that is used routinely to calibrate or check material measures, measuring instruments, or reference material Alternate Term: working measurement standard, working standard Project: ISO 17593 NOTE 1: This applies to a thromboplastin preparation used by the manufacturer during the preparation of a PT reagent mixture (ISO 17593); NOTE 2: The assigned value of the manufacturer’s working calibrator is metrologically traceable to that of the IRP (ISO 17593); NOTE 3: Material used to calibrate the “manufacturer’s standing measurement procedure.”
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manufacturer’s working calibrator calibrator produced by a specific manufacturer that is used to calibrate another measurement procedure in the calibration hierarchy for an in vitro diagnostic medical device Project: EP32 NOTE: Material typically used to calibrate the manufacturer’s standing measurement procedure.
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manufacturer’s working standard thromboplastin preparation used by the manufacturer during the preparation of a PT reagent mixture NOTE: The manufacturer's working standard is calibrated either directly or indirectly to the IRP.
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manufacturer's product calibrator calibration material provided to the customer for use with a routine clinical measurement procedure
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mapping the process of locating and identifying genes to create a genetic map Project: MM09
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marginal cost variable costs consisting of labor and material costs, plus an estimated portion of fixed costs (BusinessDictionary.com)
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marking inscription, in writing or as a graphical symbol, permanently affixed to a medical device (ISO 18113-1)
Project: ISO 18113-1, ISO 18113-2, ISO 18113-3 NOTE 1: Marking is a label permanently affixed to an IVD instrument (ISO 18113-1); NOTE 2: Adapted from IEC 61010-2-101:2002, definition 3.106 (ISO 18113-1).
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masked continuous glucose monitoring a continuous glucose monitoring system that does not provide real-time glucose concentrations to the patient Project: POCT05
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masking See blinding Alternate Term: blinding
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masking hiding; refers to a common problem seen with multiantigen HLA antibody testing in which some specificities are hidden by antibodies against other HLA that occurs on the same cell Project: ILA29
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mass accuracy agreement between the measured m/z value and the exact m/z of an ion measured to an appropriate degree of accuracy and precision Project: C64
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mass concentration (kg/L) the mass of component divided by the volume of the system containing the component (IUPAC/IFCC1978-4.8) Project: VET03
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mass fatalities plan plan describing an integrated, multidisciplinary approach to management of an incident resulting in more fatalities than can be managed by usual resources Project: GP36
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mass fraction the mass of a component divided by the mass of the system containing the component (ISO 31-8-1992)
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mass spectrometer a device that generates gas phase ions from molecules, then separates and detects these ions Project: C50
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mass spectrometer a device that generates gas phase ions from molecules and detects these ions based on the mass and charge Project: NBS04, NBS09
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mass spectrometry the study and measurement of the mass and charge of ionized molecules Project: C50, NBS04, C57, NBS09, C63 NOTE: The term “mass spectroscopy” should be avoided.
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mass spectrum a plot of ion abundance vs the ion’s mass-to-charge ratio (m/z) Project: C50 NOTE 1: While it can sometimes be assumed that the charge is one (unity), and therefore the x-axis shows mass directly, with larger molecules and with electrospray ionization, multiple charged ions are common, in which case (m/z) does not numerically equal mass; NOTE 2: Also defined as the spectrum obtained when a beam (or packet) of ions is separated according to its mass-to-charge ratios. This plot is a graphical representation of m/z vs the measured abundance information.
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mass spectrum a plot of the relative abundances of ions forming a beam or other collection as a function of their m/z values (IUPAC 2006) Project: C43
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mass spectrum when testing with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, a spectrum of ions (charged particles) arranged in order of mass-to-charge ratio (m/z) Project: M58 NOTE: When plotted graphically, mass spectra are displayed with m/z values along the x-axis, and signal intensity along the y-axis.
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mass spectrum scanning the mode of operation of a tandem mass spectrometer where the entire product mass spectrum is scanned and recorded
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match a similar sequence retrieved from a database using a search algorithm or a nucleotide at a distinct position within an alignment that is identical between all sequences aligned Project: MM18
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matching the process of making a study group and a comparison group comparable with respect to extraneous factors Project: GP45 NOTE: Several kinds of matching can be distinguished: 1) Caliper matching is the process of matching comparison group subjects to study group subjects within a specified distance for a continuous variable (eg, matching age to within two years); 2) Frequency matching requires that the frequency distributions of the matched variables be similar in study and comparison groups; 3) Category matching is the process of matching study and control group subjects in broad classes, such as relatively wide age ranges or occupational groups; 4) Individual matching relies on identifying individual subjects for comparison, each resembling a study subject on the matched variable(s); 5) Pair matching is individual matching in which study and comparison subjects are paired.
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material measure measuring instrument reproducing or supplying, in a permanent manner during its use, quantities of one or more given kinds, each with an assignedquantity value (JCGM 200:2008) Project: ISO IEC Guide 99 EXAMPLES: Standard weight, volume measure (supplying one or several quantity values, with or without a quantity value scale), standard electric resistor, linescale (ruler), gauge block, standard signal generator, certified reference material (JCGM 200:2012); NOTE 1: The indication of a material measure is its assigned quantity value (JCGM 200:2012); NOTE 2: A material measure can be a measurement standard (JCGM 200:2012).
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material measure device intended to reproduce or supply, in a permanent manner during its use, one or more known values of a given quantity (VIM93); EXAMPLES: a) a weight; b) a measure of volume (of one or several values, with or without a scale); c) a standard electrical resistor; d) a gauge block; e) a standard signal generator; f) a reference material NOTE: The quantity concerned may be called the supplied quantity. (VIM93)
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material safety data sheet technical bulletin providing detailed hazard and precautionary information (ISO 15190) Project: ISO 15190, I/LA33, POCT08 NOTE: The bulletin is provided by a supplier of a hazardous chemical substance in accordance with regulatory requirements and concerns the toxicity, health hazards, physical properties, fire, and reactivity data including storage, spill, and handling precautions.
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material safety data sheet (MSDS) document prepared in accordance with regulatory requirements for occupational safety to convey information about a hazardous chemical substance (ISO 18113-1)
Alternate Term: MSDS Project: ISO 18113-1, ISO 18113-2, ISO 18113-3 NOTE 1: Typically describes physical properties, health hazards, toxicity, fire, and reactivity properties, and provides storage and handling precautions (ISO 18113-1); NOTE 2: Material safety data sheets are not considered part of IVD medical device labeling (ISO 18113-1); NOTE 3: Adapted from US Code of Federal Regulations (CFR), Title 29, Part 1910.1200 — Hazard Communication (ISO 18113-1).
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maternal cell contamination the contamination of direct and cultured amniotic fluid, chorionic villus samples, or cord blood with maternal cells, which may be a source of error in prenatal diagnosis Project: MM01
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matrix (of a material system) totality of components of a material system except the analyte (ISO 17511) Project: ISO 17511, EP23, C62
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matrix (of a material system) components of a material system, except the analyte Project: EN 12286, ISO 15196, ISO 15197, ISO 17511, EP10, EP11, EP14, ISO 15193, ISO 15194, I/LA24, EP07, C50, MM17, I/LA33, I/LA34, M53, C56, QMS24, I/LA20, EP34, MM22, MM24, EP39 NOTE: The matrix of the calibrator, standard, and the test specimens should be comparable to maximize parallelism and ensure that the degree of nonspecific binding is comparable between the calibration and test specimen portions of the assay. Serum from a nonatopic person that is devoid of immunoglobulin E is considered an ideal diluent or protein matrix for immunoglobulin E antibody assays.
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matrix all components of a material system, except the clinically relevant analyte forms (modified from ISO 15193) Project: I/LA34 NOTE: The matrix of the calibrator, standard, and the test specimens should be comparable to maximize parallelism and ensure that the degree of nonspecific binding is comparable between the calibration and test specimen portions of the assay. Serum from a nonatopic person that is devoid of immunoglobulin E is considered an ideal diluent or protein matrix for immunoglobulin E antibody assays.
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matrix when testing with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, a solution of a phenolic acid (often α-cyano-4-hydroxycinnamic acid) in purified water plus an organic solvent (often acetonitrile and/or ethanol) Project: M58 NOTE: Whole microorganisms or extracted proteins are mixed with the matrix before matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis.
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matrix (of a material system) all components of a material system, except the measurand (modified from ISO 15193, ISO 15194) Project: EP30
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matrix the totality of all properties, other than the level of the property to be measured, that can have an effect on the measured value (ASTM)
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matrix blank a blank that incorporates only the sample without analyte Alternate Term: sample blank Project: NRSCL08
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matrix comparison equivalence of matrix types Project: EP39
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matrix effect influence of a property of the sample, other than the measurand, on the measurement of the measurand according to a specified measurement procedure and thereby on its measured value (modified from ISO 17511) Project: ISO 17511, C48, EP07, C52, H26, POCT07, GP34, EP23, C58, C56, C62, C57, POCT06, EP19, EP34, C63, EP32 NOTE 1: A specified cause of a matrix effect is an influence quantity (ISO 17511); NOTE 2: The term “matrix effect” is sometimes erroneously used for the lack of commutability due to a denatured analyte or an added nongenuine component (“surrogate analyte”) meant to simulate the analyte (ISO 17511); NOTE 3: Viscosity, surface tension, turbidity, ionic strength, and pH are common causes of matrix effects; NOTE 4: The physicochemical effect(s) (eg, interference) of the matrix on the measurement procedure’s ability to accurately measure an analyte; NOTE 5: Lipemia/turbidity is one of the common causes of matrix effect.
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matrix effect the effect of all other components of the sample, except for the measurand, on the value of the measurand Project: MM06
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matrix effect influence of a property of the sample, independent of the presence of the analyte, on the measurement and thereby on the measured quantity value (ISO 15194) Project: ISO 15194, EP26, EP14, QMS24, C49, I/LA33, EN 12287, EP39 EXAMPLE: The measurement of the amount-of-substance concentration of sodium ion in plasma by flame emission spectrometry can be influenced by the viscosity of the sample (ISO 15194); NOTE 1: A specified cause of a matrix effect is an influence quantity (ISO 15194); NOTE 2: A matrix effect depends on the detailed steps of the measurement as described in the measurement procedure (ISO 15194); NOTE 3: The physicochemical effect(s) (eg, interference) of the matrix on the measurement procedure’s ability to accurately measure an analyte.
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matrix effect all properties of a sample, other than the level of the measurand, that can affect the measured value Project: C64
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matrix-assisted laser desorption/ionization time-of-flight mass spectrometry a method that uses analysis of a spectrum of mass/charge peaks in the range of 2000 to 20 000 Daltons, which is compared to a database to arrive at an identification with similar specificity to that of sequencing the ribosomal RNA gene Project: M52
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matrix-assisted laser desorption/ionization time-of-flight mass spectrometry microorganism identification based on mass spectra generated using a matrix-assisted laser desorption/ionization time-of-flight mass spectrometry technology platform Project: MM18
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maximum allowable measurement uncertainty maximum fit-for-purpose measurement uncertainty for measurement results produced by a given measurement procedure and specified as an upper limit based on an evaluation of medical requirements (ISO 17511) Project: EP32 NOTE: The maximum allowable measurement uncertainty specification for an in vitro diagnostic medical device is abbreviated Umax(y) (ISO 17511).
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maximum analytical error the upper limit of analytical error (ie, bias, imprecision, nonspecificity) that can be tolerated without affecting the clinical use of an assay (ISO/DIS 15196 [June 2001]) Project: ISO 15196
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maximum permissible measurement error extreme value of measurement error, with respect to a known reference quantity value, permitted by specifications or regulations for a given measurement, measuring instrument, or measuring system (JCGM 200:2008) Alternate Term: maximum permissible error; limit of error Project: ISO IEC Guide 99 NOTE 1: Usually, the term "maximum permissible errors" or "limits of error" is used where there are two extreme values (JCGM 200:2012); NOTE 2: The term "tolerance" should not be used to designate ‘maximum permissible error’ (JCGM 200:2012).
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mean a measure of central tendency Alternate Term: average Project: NRSCL08
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mean (arithmetic mean) the sum of values divided by the number of values (ISO 3534-1/93- 2.26) Alternate Term: average Project: ISO 3534-1, H57 NOTE 1: The term “mean” is used generally when referring to a population parameter, and the term “average” when referring to the result of a calculation on the data obtained in a sample (ISO 3534-1/93- 2.26); NOTE 2: Despite NOTE 1, many texts and common usage interchange the words.
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mean the average of the numerical results obtained from a series of analyses
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mean (arithmetic) sum of random variables in a random sample divided by the number of terms in the sum Alternate Term: average Project: C24 NOTE: The sample mean considered as a statistic is often used as an estimator for the population mean. A common synonym is arithmetic mean.
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mean absolute difference (MAD) expected value of the absolute deviation between the measurements of a procedure or system and matched reference values (or true values if available). Often estimated by the average of the absolute difference across N measurements/reference pairs indexed by i (see equation in POCT05)
Project: POCT05
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mean absolute relative difference (MARD) expected value of the absolute relative deviation (ARD) between the measurements of a procedure or system and matched reference values (or true values if available). Often estimated by the average of the absolute relative difference across N measurements/reference pairs indexed by i (see equation in POCT05)
Project: POCT05
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mean cell volume the average volume of the red blood cells in a given blood sample; expressed in femtoliter, 10-15 L Project: H07 NOTE: Mean cell volume was previously reported in cubic micrometers, µm3.
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mean corpuscular hemoglobin the average amount of hemoglobin contained within the individual red cell Project: NRSCL08 NOTE: The MCH, expressed as the amount of hemoglobin in picogram (10-12 grams), is calculated as follows
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mean corpuscular hemoglobin concentration the average hemoglobin concentration within the red blood cells Project: H07, H15
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mean kinetic temperature a single derived temperature that, if maintained over a defined period of time, affords the same thermal challenge to a substance or product as would be experienced over a range of both higher and lower temperatures for an equivalent defined period. The MKT is higher than the arithmetic mean temperature and takes into account the Arrhenius equation Project: EP25
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mean normal prothrombin time the geometric mean of the prothrombin times of the healthy adult population (WHO 880) Project: H54, H47, H57 NOTE 1: For practical purposes, the geometric mean of the prothrombin time calculated from at least 20 fresh samples from healthy individuals, including those of both sexes, is a reliable approximation of mean normal prothrombin time. It is not necessary to collect and test all the individual samples in one session (WHO 880); NOTE 2: It is recommended that each laboratory should determine mean normal prothrombin time using its own prothrombin-time system (WHO 880); NOTE 3: The arithmetic mean should not be used.
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measurand quantity intended to be measured (JCGM 200:2012) Project: MM13, EP10, ISO IEC Guide 99, GP16, H58, EP12, POCT05, I/LA21, EP25, C34, EP18, GP33, M55, POCT09, ISO 18113-1, H26, POCT07, MM06, M24, H59, I/LA28, GP34, H02, EP23, C58, MM19, NBS05, EP24, C51, MM01, EP17, C56, EP27, MM20, MM14, MM07, EP09, EP26, C40, MM22, EP06, PRE01, MM09, H60, EP14, C62, EP05, EP15, C57, MM03, MM23, POCT06, EP19, GP47, GP40, EP33, H48, C64, POCT04, QMS24, C24, QMS03, NBS09, EP34, EP07, EP31, C52, NBS07, C63, MM17, C49, EP30, EP35, MM24, EP39, H62, PRE04, NBS10, EP32, POCT16 EXAMPLE 1: The potential difference between the terminals of a battery may decrease when using a voltmeter with a significant internal conductance to perform the measurement. The open-circuit potential difference can be calculated from the internal resistances of the battery and the voltmeter (JCGM 200:2012); EXAMPLE 2: The length of a steel rod in equilibrium with the ambient temperature of 23°C will be different from the length at the specified temperature of 20°C, which is the measurand. In this case, a correction is necessary (modified from JCGM 200:2012); EXAMPLE 3: Vapor pressure of a given sample of water at 20°C; EXAMPLE 4: The “mass of protein in 24-hour urine from a given person at a given time” is a measurand. The component “protein” is sometimes termed “analyte”; EXAMPLE 5: The “amount-of-substance of glucose in plasma of a given person at a given time” is a measurand with the component “glucose”; EXAMPLE 6: The colloquial term “calcium” usually refers to either of the measurands “amount-of-substance concentration of total calcium in serum of a given person at a given time” or “amount-of-substance concentration of ionized calcium in serum of a given person at a given time.” In the first case, total calcium includes all fractions, which comprise free calcium ions (ie, ionized calcium) and bound calcium (ie, complex-bound calcium and protein-bound calcium); EXAMPLE 7: S-Creatinine concentration is frequently measured using an enzyme-based technique resulting in a color reaction. Results will be biased due to different specificity of the measurement procedures and different quantities measured; EXAMPLE 8: The enzymatic activity of alkaline phosphatase at 37°C; EXAMPLE 9: The concentration of testosterone in serum is a measurand, but testosterone alone is an analyte; NOTE 1: The specification of a measurand requires knowledge of the kind of quantity, description of the state of the phenomenon, body, or substance carrying the quantity, including any relevant component, and the chemical entities involved (JCGM 200:2012); NOTE 2: In the second edition of the VIM and in IEC 60050-300:2001, the measurand is defined as the “particular quantity subject to measurement” (JCGM 200:2012); NOTE 3: The measurement, including the measuring system and the conditions under which the measurement is carried out, might change the phenomenon, body, or substance such that the quantity being measured may differ from the measurand as defined. In this case, adequate correction is necessary (JCGM 200:2012); NOTE 4: In chemistry, “analyte,” or the name of a substance or compound, is a term sometimes used for “measurand.” This usage is erroneous because these terms do not refer to quantities (JCGM 200:2012); NOTE 5: In chemistry, “analyte,” or the name of a substance or compound, are sometimes used for “measurand.” This usage is erroneous because these terms do not refer to quantities, but only to a component of the measurand (modified from JCGM 200:2012); NOTE 6: The term “measurand” and its definition encompass all quantities, while the commonly used “analyte” refers to a tangible entity subject to measurement (ie, the measurand describes what is causing the result of the measurement, and the analyte describes the particular component of interest to the patient). For example, “substance” concentration is a quantity that can be related to a particular analyte; NOTE 7: The term “analyte” is not intended to be used for “measurand.” Analyte is a component of a measurand; NOTE 8: In the designation “Blood–Glucose; amount-of-substance concentration,” the term “Glucose” designates the analyte, equal to the component; NOTE 9: The specification of a measurand in laboratory medicine requires knowledge of the kind of quantity (eg, mass concentration), a description of the matrix carrying the quantity (eg, blood plasma), and the chemical entities involved (eg, the analyte) (ISO 18113-1); NOTE 10: The measurand can be a biological activity (ISO 18113-1); NOTE 11: See 3.3 for other examples of in vitro diagnostic measurands (ISO 18113-1); NOTE 12: For example, the elements of a complete blood count or leukocyte differential; NOTE 13: Do not use the term “parameter” as a synonym for measurand, because it does not refer to a quantity; NOTE 14: For blood cells, the automated hematology instrument generally does not specifically identify the reportable elements (red blood cells, white blood cells, platelets) but rather uses sizing thresholds and other discriminant algorithms to classify the particles sensed and counted. In other words, the measurand is not necessarily what is being measured; NOTE 15: In CLSI document MM06, the measurand is also referred to as (or is synonymous with) the term “target”; NOTE 16: A measurand can refer to an analyte concentration, a clotting time, an enzyme activity, an epitope, etc., in a particular sample type; NOTE 17: Component represented in the name of a measurable quantity (ISO 17511); NOTE 18: In the type of quantity described in “viral load present in blood for HIV-1 RNA,” “HIV-1 RNA” is the analyte and the long phrase represents the measurand; NOTE 19: In the type of quantity “catalytic concentration of lactate dehydrogenase isoenzyme 1 in plasma,” “lactate dehydrogenase isoenzyme 1” is the analyte (ISO 18153); NOTE 20: The term “measurand” and its definition encompass all quantities, while the commonly used term “analyte” refers to a tangible entity subject to measurement (eg, “substance” concentration is a quantity that may be related to a particular analyte); NOTE 21: In the type of quantity “mass of protein in 24-hour urine,” “protein” is the analyte. In “amount of substance of glucose in plasma,” “glucose” is the analyte. In both cases, the long phrase represents the measurand (ISO 17511); NOTE 22: For a qualitative measurement procedure, the measurand is the presence of the analyte of interest; NOTE 23: The term “measurand” and its definition encompass all quantities, while the commonly used term “analyte” refers to a tangible entity subject to measurement; NOTE 24: The term “measurand” and its definition encompass all quantities, while the commonly used term “analyte” refers to a tangible entity subject to measurement (eg, “substance” concentration or activity is a quantity that may be related to a particular analyte); NOTE 25: The specification of a measurand may require statements about quantities such as time, temperature, and pressure; NOTE 26: In EXAMPLE 3, the measurand includes not only the entity being measured (water), but the particular quality being measured (vapor pressure), and the specific environmental condition under which it is being measured (20°C); NOTE 27: In EXAMPLE 8, the measurand includes not only the entity being measured (alkaline phosphatase), but the particular measurand being measured (enzymatic activity) and the specific environmental condition under which it is being measured (37°C); NOTE 28: The term “measurand” and its definition encompass all quantities, while the commonly used term “analyte” refers to a tangible entity subject to measurement (ie, the measurand describes what is causing the result of the measurement, the analyte, and the medium or base [eg, activity of the enzyme alkaline phosphatase in serum], and the analyte describes the particular component of interest to the patient); NOTE 29: The specification of a measurand for a quantitative examination requires knowledge of the kind of quantity, description of the state of the phenomenon, body, or substance carrying the quantity, including any relevant component, and the chemical entities involved (JCGM 200:2012); NOTE 30: Although qualitative examinations can have an underlying signal that is specified in a manner similar to that noted above for quantitative examinations, the primary purpose of a qualitative examination is to describe rather than quantify. Therefore, specification of a measurand for a qualitative examination necessitates knowledge of the underlying signal plus the location of the cutoff in this signal scale and a description of the two mutually exclusive states intended to be categorized; NOTE 31: The term “measurand" encompasses all quantities, while the commonly used “analyte” refers to a tangible entity subject to measurement. The concentration of a named “measurand" is a quantity that may be related to a particular analyte, eg, the concentration of testosterone in serum is an example of a measurand, but testosterone alone is an example of an analyte; NOTE 32: Generally includes the "analyte" as measured with respect to specific conditions. Examples include glucose in blood plasma, protein in 24-hour urine, and cholesterol in blood serum; NOTE 33: In general, quantitative measurement procedures determine measurands, while qualitative measurement procedures determine analytes; NOTE 34: The term “analyte” must not be used for “measurand”; NOTE 35: The specification of a measurand requires knowledge about quantities such as time, temperature, and pressure; NOTE 36: See analyte.
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measurand drift change in intended quantity measured through time Project: EP25
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measured quantity value quantity value representing a measurement result (JCGM 200:2012) Alternate Term: measured value of a quantity; measured value Project: ISO IEC Guide 99, C51, EP19 NOTE 1: For a measurement involving replicate indications, each indication can be used to provide a corresponding measured quantity value. This set ofindividual measured quantity values can be used to calculate a resulting measured quantity value, such as an average or median, usually with a decreased associatedmeasurement uncertainty (JCGM 200:2012); NOTE 2: When the range of the true quantity values believed to represent the measurand is small compared with the measurement uncertainty, a measured quantity value can be considered to be an estimate of an essentially unique true quantity value and is often an average or median of individual measured quantity values obtained through replicate measurements (JCGM 200:2012); NOTE 3: In the case where the range of the true quantity values believed to represent the measurand is not small compared with the measurement uncertainty, a measured value is often an estimate of an average or median of the set of true quantity values (JCGM 200:2012); NOTE 4: In the GUM, the terms "result of measurement" and "estimate of the value of the measurand" or just "estimate of the measurand" are used for ‘measured quantity value’ (JCGM 200:2012).
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measured value See measured quantity value Alternate Term: measured quantity value; measured value of a quantity Project: C51
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measured value of a quantity See measured quantity value Alternate Term: measured quantity value; measured value Project: C51
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measurement process of experimentally obtaining one or more quantity values that can reasonably be attributed to a quantity (JCGM 200:2012) Project: ISO IEC Guide 99, EP18, ISO 18113-1, EP23, C51 NOTE 1: Measurement does not apply to nominal properties (JCGM 200:2012); NOTE 2: Measurement implies comparison of quantities and includes counting of entities (JCGM 200:2012); NOTE 3: Measurement presupposes a description of the quantity commensurate with the intended use of a measurement result, a measurement procedure, and a calibrated measuring system operating according to the specified measurement procedure, including the measurementconditions (JCGM 200:2012); NOTE 4: In chemistry, “analyte”, or the name of a substance or compound, are terms sometimes used for “measurand”. This usage is erroneous because these terms do not refer to quantities (ISO 18113-1); NOTE 5: The operations can be performed automatically (ISO 18113-1).
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measurement bias See bias Alternate Term: bias Project: C51
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measurement error the result of a measurement minus a true value (or accepted reference value) of the measurand (VIM93) Alternate Term: error of measurement Project: H57 NOTE: Formerly, the term total error was used in CLSI/NCCLS documents.
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measurement error See error Alternate Term: error; error of measurement Project: C51, MM20, H60
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measurement function function of quantities, the value of which, when calculated using known quantity values for the input quantities in a measurement model, is ameasured quantity value of the output quantity in the measurement model (JCGM 200:2008) Project: ISO IEC Guide 99, C51 NOTE 1: If a measurement model h(Y, X1, …, Xn) = 0 can explicitly be written as Y = f (X1, …, Xn), where Y is the output quantity in the measurement model, the function f is the measurement function. More generally, f maysymbolize an algorithm, yielding for input quantity values x1, …, xn a corresponding unique output quantity valuey = f (x1, …, xn) (JCGM 200:2012); NOTE 2: A measurement function is also used to calculate the measurement uncertainty associated with the measured quantity value of Y (JCGM 200:2012).
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measurement method generic description of a logical organization of operations used in a measurement (ISO 18113-1) Alternate Term: method of measurement Project: ISO IEC Guide 99, EP12, ISO 18113-1, EP15, EP34 NOTE 1: Measurement methods may be qualified in various ways such as:
— substitution measurement method,
— differential measurement method, and
— null measurement method; or
— direct measurement method, and
— indirect measurement method. See IEC 60050-300:2001 (JCGM 200:2012);
NOTE 2: A measurement method is used in a specific measurement procedure (3.44) (ISO 18113-1);
NOTE 3: Measurement methods can be qualified in various ways such as direct measurement method and indirect measurement method. See IEC 60050-300 for further information (ISO 18113-1).
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measurement method logical sequence of operations, described generically, used in the performance of measurements (VIM93) Project: ISO CD 18113-1, ISO CD 18113-2, ISO CD 18113-3 NOTE: A measurement method is used in a specific measurement procedure. See the definition of measurement procedure.
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measurement model mathematical relation among all quantities known to be involved in a measurement (JCGM 200:2012) Alternate Term: model of measurement, model Project: ISO IEC Guide 99, ISO 18113-1, C51 NOTE 1: A general form of a measurement model is the equation h(Y, X1, …, Xn) = 0, where Y, the output quantity in the measurement model, is the measurand, the quantity value of which is to be inferred from information about input quantities in the measurement model X1, …, Xn (JCGM 200:2012); NOTE 2: In more complex cases where there are two or more output quantities in a measurement model, the measurement model consists of more than one equation (JCGM 200:2012); NOTE 3: In clinical chemistry, measurement models have also been called calibration models (ISO 18113-1); EXAMPLE: Four-parameter logistic function for fitting sigmoidal measurement indications to calibrator concentrations in immunochemical measurement procedures (ISO 18113-1).
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measurement precision See precision Alternate Term: precision Project: C51
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measurement principle phenomenon serving as a basis of a measurement (JCGM 200:2012) Alternate Term: principle of measurement Project: ISO IEC Guide 99, ISO 18113-1 EXAMPLE 1: Thermoelectric effect applied to the measurement of temperature (JCGM 200:2012); EXAMPLE 2: Energy absorption applied to the measurement of amount-of-substance concentration (JCGM 200:2012); EXAMPLE 3: Lowering of the concentration of glucose in blood in a fasting rabbit applied to the measurement of insulin concentration in a preparation (JCGM 200:2012); EXAMPLE 4: a) Ion selective electrode applied to the measurement of sodium activity; b) Antibody affinity applied to the measurement of thyroid stimulating hormone (TSH) concentration; c) Liquid chromatography applied to the measurement of digoxin concentration (ISO 18113-1); NOTE: The phenomenon can be of a physical, chemical, or biological nature (JCGM 200:2012).
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measurement principle phenomenon serving as a basis of a measurement (JCGM 200:2012) Alternate Term: principle of measurement Project: ISO 18113-1 NOTE: The phenomenon can be of a physical, chemical, or biological nature (JCGM 200:2012).
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measurement procedure detailed description of a measurement according to one or more measurement principles and to a given measurement method, based on a measurement model and including any calculation to obtain a measurement result (JCGM 200:2012) Project: ISO IEC Guide 99, EP12, POCT05, I/LA21, C34, I/LA33, ISO 18113-1, MM06, H59, I/LA28, C58, EP10, C51, MM01, EP27, MM14, EP26, C40, MM22, H60, EP06, EP14, EP05, C62, EP15, C57, MM23, POCT06, POCT04, C24, EP34, EP31, EP35 NOTE 1: A measurement procedure is usually documented in sufficient detail to enable an operator to perform a measurement (JCGM 200:2012); NOTE 2: A measurement procedure can include a statement concerning a target measurement uncertainty (JCGM 200:2012); NOTE 3: A measurement procedure is sometimes called a standard operating procedure (JCGM 200:2012); NOTE 4: This term pertains to specific procedures as marketed by specific manufacturers; NOTE 5: In other documents, equivalent terms were method, device, and assay; NOTE 6: A measurement procedure is based on a measurement method; NOTE 7: In CLSI EP05, “assay” is sometimes used as a stylistic variant for “measurement procedure”; NOTE 8: A qualitative measurement procedure reports nominal values, eg, the presence or absence of the analyte without quantification; NOTE 9: A quantitative measurement procedure generates a spectrum of signal responses that are directly proportional to the measurand levels. If the analyte preparations with known concentrations are available for calibration, the actual concentration of the analyte can be determined; NOTE 10: A semiquantitative measurement procedure is essentially a qualitative measurement procedure with an additional option for a response range (degree of positivity, dilution to which positive results are obtained, or comparison to a color chart), and may use an ordinal scale; NOTE 11: For the purposes of CLSI EP19, includes the hardware, software, reagents, calibrators, and any other items needed to obtain a clinically relevant result; NOTE 12: For the purposes of CLSI EP21, measurement procedures provide quantitative results; NOTE 13: Formerly, the term “analytical method” was used in CLSI C24; NOTE 14: Formerly in CLSI C34, the term “analytical method” was used; NOTE 15: For CLSI EP35, “measurement procedure” is intended to include both quantitative and qualitative examinations; NOTE 16: Typically used to describe a quantitative examination; NOTE 17: See assay.
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measurement procedure set of operations, described specifically, used in the performance of particular measurements according to a given method (ISO 17511) Project: ISO 17511, I/LA23, ISO 17593, MM12, ISO 18113, C50, H57 NOTE 1: A measurement procedure is usually recorded in a document that is sometimes itself called a “measurement procedure” (or a measurement method) and is usually in sufficient detail to enable an operator to carry out a measurement without additional information; NOTE 2: This term pertains to specific procedures as marketed by specific manufacturers; NOTE 3: In other documents and in EP15, equivalent terms were method, device, and assay; NOTE 4: A measurement procedure is based on a measurement method. See the definition of measurement method; NOTE 5: Formerly, the term “analytical method” was used in C24.
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measurement procedure a written specification for how a measurement is performed, including a technical description of reagents, calibrators, equipment, instrument, and other details necessary to operate a measuring system that implements those specifications Project: EP30
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measurement range range of analyte concentrations over which meaningful results can be acquired Project: POCT04
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measurement result set of quantity values being attributed to a measurand together with any other available relevant information Alternate Term: result of measurement Project: C51 NOTE 1: A measurement result generally contains “relevant information” about the set of quantity values, such that some may be more representative of the measurand than others. This may be expressed in the form of a probability density function; NOTE 2: A measurement result is generally expressed as a single measured quantity value and a measurement uncertainty. If the measurement uncertainty is considered to be negligible for some purpose, the measurement result may be expressed as a single measured quantity value. In many fields, this is the common way of expressing a measurement result; NOTE 3: In the traditional literature and in the previous edition of the VIM, measurement result was defined as a value attributed to a measurand and explained to mean an indication, or an uncorrected result, or a corrected result, according to the context (JCGM 200:2008 § 2.9).
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measurement sensitivity quotient of the change in an indication and the corresponding change in the value of a quantity being measured (modified from ISO 15193) Project: mm23
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measurement standard material measure, measuring instrument, reference material, or measuring system intended to define, realize, conserve, or reproduce a unit or one or more values of a quantity to serve as a reference (ISO 17511) Project: ISO 17511 NOTE 1: A given measurement standard with an assigned value for one quantity can sometimes serve as a reference material for measurement procedures yielding values for more than one type of quantity. (For example, a reference material for cholesterol also serving for cholesterol esters that are measured after hydrolysis as cholesterol.) (ISO 17511); NOTE 2: The term "standard" is used with two meanings: "measurement standard" and "written standard". The full terms should be used when doubt can arise (ISO 17511).
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measurement system a unit or device used to measure or assess the presence or absence of a particular substance, or to quantitate that substance, found in blood or body fluids Project: EP31 NOTE: A measurement system includes instructions and all of the instrumentation, equipment, reagents, and/or supplies needed to perform an assay or examination and generate test results.
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measurement uncertainty parameter, associated with the result of a measurement, that characterizes the dispersion of the values that could reasonably be attributed to the measurand Project: EP32
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measurement unit real scalar quantity, defined and adopted byconvention, with which any other quantity of thesame kind can be compared to express the ratio ofthe two quantities as a number (JCGM 200:2008) Alternate Term: unit of measurement; unit Project: ISO IEC Guide 99 NOTE 1: Measurement units are designated by conventionally assigned names and symbols (JCGM 200:2012); NOTE 2: Measurement units of quantities of the same quantity dimension may be designated by the same name and symbol even when the quantities are not of the same kind. For example, joule per kelvin and J/K are respectively the name and symbol of both a measurement unit of heat capacity and a measurement unit of entropy, which are generally not considered to be quantities of the same kind. However, in some cases special measurement unit names are restricted to be used with quantities of a specific kind only. For example, the measurement unit ‘second to the power minus one’ (1/s) is called hertz (Hz) when used for frequencies and becquerel (Bq) when used for activities of radionuclides (JCGM 200:2012); NOTE 3: Measurement units of quantities of dimension one are numbers. In some cases, these measurement units are given special names, eg, radian, steradian, and decibel, or are expressed by quotients such as millimole per mole equal to 10-3 and microgram per kilogram equal to 10-9 (JCGM 200:2012); NOTE 4: For a given quantity, the short term "unit" is often combined with the quantity name, such as "mass unit" or "unit of mass" (JCGM 200:2012).
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measurement unit a particular quantity, defined and adopted by convention, with which other quantities of the same kind are compared in order to express their magnitudes relative to that quantity (VIM93) Alternate Term: unit of measurement Project: Unit NOTE 1: Units of measurement have conventionally assigned names and symbols; NOTE 2: Units of quantities of the same dimension may have the same names and symbols even when the quantities are not of the same kind. (VIM93-1.7)
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measurement unit the unit in which instrument or system results are expressed Alternate Term: unit of measurement Project: NRSCL08
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measuring chain series of elements of a measuring system constituting a single path of the signal from a sensor to an output element (JCGM 200:2008) Project: ISO IEC Guide 99 EXAMPLE 1: Electro-acoustic measuring chain comprising a microphone, attenuator, filter, amplifier, and voltmeter (JCGM 200:2012); EXAMPLE 2: Mechanical measuring chain comprising a Bourdon tube, system of levers, two gears, and a mechanical dial (JCGM 200:2012).
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measuring chain series of elements of a measuring instrument or system that constitutes the path of the measurement signal from the input to the output (VIM93); EXAMPLE an electro-acoustic measuring chain comprising a microphone, attenuator, filter, amplif'ter and voltmeter Project: VIM93
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measuring instrument device used for making measurements, alone or in conjunction with one or more supplementary devices (JCGM 200:2012) Project: ISO IEC Guide 99 NOTE 1: A measuring instrument that can be used alone is a measuring system (JCGM 200:2012); NOTE 2: A measuring instrument may be an indicating measuring instrument or a material measure (JCGM 200:2012); NOTE 3: For the purpose of this guideline, the measurements made by instruments contribute directly to examination results.
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measuring instrument device intended to be used to make measurements, alone or in conjunction with supplementary device(s) (VIM93)
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measuring interval set of values of quantities of the same kind that can be measured by a given measuring instrument or measuring system with specified instrumental measurement uncertainty, under defined conditions (JCGM 200:2012) Project: ISO 17593, MM01, MM22, EP19, EP10 NOTE 1: The measuring interval is intended to refer to the interval of values that a measurement procedure can directly measure on the sample without any dilution, concentration, or other pretreatment not part of the usual measurement process; NOTE 2: The measuring interval has been called the analytical measurement range, analytical range, and calibration range; NOTE 3: The concentration range of results for which the test method functions to meet its intended use; NOTE 4: Measuring interval is determined by linearity, accuracy, and limit of detection; NOTE 5: This represents the interval of in vitro diagnostic examination results over which the performance characteristics of the in vitro diagnostic medical device were validated by the manufacturer; NOTE 6: The measuring interval over which the performance characteristics of an in vitro diagnostic medical device have been validated has been called the reportable range; NOTE 7: See reportable range.
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measuring interval (of an IVD medical device) set of values of measurands for which the uncertainty of an IVD medical device is intended to lie within specified limits Project: ISO CD 18113-1, ISO CD 18113-2, ISO CD 18113-3 NOTE 1: This represents the interval of IVD examination results over which the performance characteristics of the IVD medical device have been validated by the manufacturer; NOTE 2: May be referred to as "reportable range" in some laboratory quality systems.
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measuring interval the upper and lower values, between which the test system will give accurate results Project: POCT08 NOTE: Alternative terms are “reportable range” and “analytical measurement range.”
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measuring range set of values of measurands for which the error of a measuring instrument is intended to lie within specified limits (VIM93) Alternate Term: working range; reportable range Project: H44, I/LA21, MM10, I/LA02, H56, VET03, C50 NOTE 1: “Error” is determined in relation to a conventional true value (VIM93); NOTE 2: In some fields of knowledge, the difference between the greatest and smallest values is called range (VIM93); NOTE 3: For EP06, the range of values (in units appropriate for the analyte [measurand]) over which the acceptability criteria for the method have been met; that is, where errors due to nonlinearity, imprecision, or other sources are within defined limits; NOTE 4: Formerly, the term “reportable range” was used in CLSI/NCCLS documents.
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measuring range See measuring interval Alternate Term: measuring interval Project: C56
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measuring system set of one or more measuring instruments and often other devices, including any reagent, calibrator, and supply, assembled and adapted to provide information used to generate measured quantity values within specified intervals for quantities of specified kinds (JCGM 200:2012) Project: ISO IEC Guide 99, EP23, C51, C56, EP06, EP07, EP32 NOTE: A measuring system may consist of only one measuring instrument (JCGM 200:2012).
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measuring system a physical in vitro diagnostic medical device manufactured according to the measurement procedure specifications and used to make measurements on clinical samples to produce results (quantity values) that are used in research and to make medical decisions for patient care Project: EP30
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measuring transducer device, used in measurement, that provides an output quantity having a specified relation to the input quantity (JCGM 200:2012) Project: ISO IEC Guide 99 EXAMPLES: Thermocouple, electric current transformer, strain gauge, pH electrode, Bourdon tube, bimetallic strip (JCGM 200:2012).
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measuring transducer device that provides an output quantity having a determined relationship to the input quantity (VIM93); EXAMPLES: a) thermocouple; b) current transformer; c) strain gauge; d) pH electrode
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mechanical method of clot detection technology that depends on a mechanical interaction with the fibrin clot formation Project: H48 NOTE 1: Clot detection is dependent on the instrument hardware; NOTE 2: When a clot forms, there is a change in range of motion or a break in contact with the magnetic sensors, or the ball swings in a pendulum motion, and increased viscosity causes the ball to stop and signals the formation of a clot (Koepke JA.Technologies for coagulation instruments. Lab Medicine. 2000;31(4):211-216).
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meconium the infant’s first stool composed of intestinal epithelial cells, lanugo, mucus, bile, and water that is sometimes expelled into amniotic fluid before birth Project: C58
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meconium ileus a specific form of neonatal intestinal obstruction with abdominal distention that can occur when a fetus with two cystic fibrosis–causing mutations has dehydrated, viscous small intestinal contents that obstruct the terminal ileum and lead to a very narrow large bowel (“microcolon”) that is not evacuated after birth Project: NBS05 NOTE: Meconium ileus is the presenting sign of cystic fibrosis in about 20% of patients.
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media data storage material divided into four broad categories according to the recording method: 1) paper; 2) magnetic, such as diskettes, disks, or tapes; 3) optical, such as microfiche; and 4) magneto-optical, such as compact discs and digital video discs Project: QMS26
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medial pertaining to the middle; closer to the median plane or midline of a body or structure (Dorland's Illustrated Medical Dictionary. 33rd ed. Elsevier, Inc.; 2019) Project: PRE02
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median (average) the middle number or value in an ordered series (ISO 3534-1/93-2.28) Project: ISO 3534-1/93-2.28 NOTE: If n values are arranged in nondecreasing order of magnitude and numbered 1 to n, the median of these n values is the [( n + 1)/2]th value if n is odd; if n is even, the median lies between the (n/2)th and the [(n/2) + 1]th values and is not defined uniquely. Unless otherwise specified, it may be taken to be the arithmetic mean of these two values.
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median situated in or near the midline of a body or structure (Dorland's Illustrated Medical Dictionary. 33rd ed. Elsevier, Inc.; 2019) Project: PRE02
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medical alert values assay values that may require immediate medical attention, due to dangerously abnormal levels of a particular analyte Alternate Term: critical values Project: AST02, AUTO10 NOTE: Also called “critical values.”
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medical data device language used as the upper-layer protocol for ISO/IEEE 11073 devices Project: POCT01
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medical decision points analyte values at which medical professionals can determine whether a patient may be suffering from a certain condition or treatment needs to be changed Project: H62 NOTE: Patient test results are compared with the medical decision points so that appropriate diagnoses or medical interventions can be made.
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medical device any instrument, apparatus, implement, machine, appliance, implant, in vitro reagent or calibrator, software, material, or other similar or related article, intended by the manufacturer to be used, alone or in combination, for human beings for one or more specific purpose(s) (ISO/DIS 14971) Alternate Term: device, medical accessories, medical products, medical supplies Project: HS11, ISO/DIS 14971, POCT09, NBS01 NOTE 1: Specific purposes may include: diagnosis, prevention, monitoring, treatment, or alleviation of disease; diagnosis, monitoring, treatment, alleviation of, or compensation for an injury; investigation, replacement, modification, or support of the anatomy or of a physiological process; supporting or sustaining life, control of conception; disinfection of medical devices (regulated as drugs in some jurisdictions); providing information for medical purposes by means of in vitro examination of specimens derived from the human body; and which does not achieve its primary intended action in or on the human body by pharmacological, immunological, or metabolic means, but which may be assisted in its intended function by such means (FDA); NOTE 2: This definition has been developed by the Global Harmonization Task Force (ISO 13485:2003); NOTE 3: The definition of a device for in vitro examination includes, for example, reagents, calibrators, sample collection devices, control materials, and related instruments or apparatus. The information provided by such an in vitro diagnostic device may be for diagnostic, monitoring, or compatibility purposes. In some jurisdictions, some in vitro diagnostic devices, including reagents and the like, may be covered by separate regulations; NOTE 4: Products, which may be considered to be medical devices in some jurisdictions but for which there is not yet a harmonized approach, are: aids for disabled/handicapped people; devices for the treatment/diagnosis of diseases and injuries in animals; accessories for medical devices (see NOTE 5); disinfection substances; and devices incorporating animal and human tissues which may meet the requirements of the above definition but are subject to different controls; NOTE 5: Accessories intended specifically by manufacturers to be used together with a “parent” medical device to enable that medical device to achieve its intended purpose, should be subject to this standard.
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medical device instrument, apparatus, appliance, material, or other article, whether used alone or in combination, including the software necessary for its proper application intended by the organization to be used for human beings for the purpose of: diagnosis, prevention, monitoring, treatment, or alleviation of disease; diagnosis, monitoring, treatment, alleviation of, or compensation for, an injury or handicap; investigation, replacement, or modification of the anatomy or of a physiological process; or control of conception, and which does not achieve its principal intended action in or on the human body by pharmacological, immunological, or metabolic means, but which may be assisted in its function by such means (modified from ISO 13485) Project: ISO 18113-1, ISO 18113-2, ISO 18113-3 NOTE 1: The term "medical device" includes in vitro diagnostic medical devices (ISO 18113-1); NOTE 2: This is the definition adopted by the GHTF in Global Harmonization Task Force (GHTF), Information Document Concerning the Definition of the Term “Medical Device”, Final Document GHTF/SG1/N29R16:2005, 20 May 2005 (ISO 18113-1); NOTE 3: See Clause 3 of ISO 13485:2003 for additional examples of medical devices (ISO 18113-1).
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medical device any instrument, apparatus, implement, machine, appliance, implant, in vitro reagent or calibrator, software, material or other similar or related article, intended by the manufacturer to be used, alone or in combination, for human beings for one or more of the specific purpose(s) of: – diagnosis, prevention, monitoring, treatment, or alleviation of disease – diagnosis, monitoring, treatment, alleviation of, or compensation for an injury – investigation, replacement, modification, or support of the anatomy or of a physiological process – supporting or sustaining life – control of conception – disinfection of medical devices – providing information for medical purposes by means of in vitro examination of specimens derived from the human body, and which does not achieve its primary intended action in or on the human body by pharmacological, immunological or metabolic means, but which may be assisted in its function by such means (ISO/IEC Guide 63) Project: M52 NOTE 1: The medical devices in M52 are microbial identification and antimicrobial susceptibility testing systems; NOTE 2: In the context of M52, device is synonymous with product; NOTE 3: See product.
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medical device manufacturer person or company that makes or supplies the in vitro diagnostic instrument or software system Project: AUTO11
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medical error any preventable event that may cause or lead to inappropriate medication use or patient harm while the medication is in control of the healthcare professional, patient, or consumer NOTE: Such events may be related to professional practice, healthcare product, procedures, and systems, including prescribing; order communication; education; monitoring; and use.
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medical home characteristics include accessible, continuous, comprehensive, family-centered, coordinated, compassionate, and culturally effective medical care of infants, children, and adolescents that should be delivered or directed by well-trained health care providers who provide primary care and help to manage and facilitate essentially all aspects of pediatric care Project: NBS05 NOTE: The health care provider should be known and should be able to develop a partnership or mutual responsibility and trust with the child and family.
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medical information bus a common name used for the IEEE 1073 family of standards for medical device communications (See IEEE 1073.) Project: POCT01, POCT02 NOTE: Not to be confused with management information base used in simple network management protocol.
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medical information bus a communication service designed for intensive care unit, operating room, and emergency room bedside devices (IEEE) Project: AUTO01, AUTO02, AUTO03
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medical laboratory laboratory for the biological, microbiological, immunological, chemical, immunohematological, hematological, biophysical, cytological, pathological, genetic, or other examination of materials derived from the human body for the purpose of providing information for the diagnosis, management, prevention, and treatment of disease in, or the assessment of the health of, human beings, and which may provide a consultant advisory service covering all aspects of laboratory investigation including the interpretation of results and advice on further appropriate investigation (ISO 15189) Alternate Term: clinical laboratory Project: ISO 15189, MM01, MM14, MM22, GP48, GP49, MM24 NOTE 1: These examinations also include procedures for determining, measuring, or otherwise describing the presence or absence of various substances or microorganisms (ISO 15189); NOTE 2: In the United States, the term “clinical laboratory” is used.
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medical laboratory See clinical laboratory
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medical laboratory quality a set of well-defined and well-executed processes that create a system for the collection, examination, and reporting of human samples that: supports diagnosis, preventions, and management of disease states; generates information having clinical utility and optimal impact on health outcomes; meets predetermined targets for accuracy, reproducibility, and traceability; strives to minimize error; is timely, safe, efficient, cost-effective; and focuses on client satisfaction and continual improvement (ISO/PDTR 22869) Project: ISO PDTR 22869 NOTE: [ISO/PDTR 22869] The supply chain terminology (supplier→organization→customer) used in the ISO 9000 series when applied to a medical laboratory can refer to a supplier as a company that supplies reagents, kits, or devices care as well as a provider of patients or patient samples. The term organization can be used to refer to the laboratory itself or to the management structure within which the laboratory resides. The term customer is often used to refer to the individual who ordered a laboratory test, but can also be thought of as the patient.
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medical review officer a licensed physician responsible for receiving and reviewing laboratory results generated by an employer’s drug testing program and evaluating possible medical explanations for positive drug test results Project: C52
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medical significance in the context of evaluating a measurement procedure, the importance of an error due to its potential to alter a medical caregiver’s diagnosis, treatment, or management of a patient Project: EP07
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medical waste that portion of the infectious waste stream regulated by the authority having jurisdiction and may require some decontamination treatment Project: M29, POCT10 NOTE: See regulated waste and regulated medical waste.
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medically allowable total error maximum error in a laboratory test result that can be tolerated before medical decision-making is affected Project: EP26 NOTE: Medically allowable total error includes pre- and postexamination errors.
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MEDIX a data model for medical data interchange between diverse systems (IEEE) Project: AUTO01, AUTO02, AUTO03
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meeting record permanent formal record of an official meeting Project: QMS14
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melting curve analysis an assessment of the dissociation characteristics of double-stranded DNA during heating, used to infer the presence and identity of single nucleotide polymorphisms Project: MM19
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melting temperature temperature at which one half of complementary DNA molecules exist as a double-stranded complex and the other half as single strands Project: MM22, MM24
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melting temperature temperature at which a double-stranded DNA or RNA molecule denatures into single strands. The melting temperature is characteristic of each DNA species and gives an indication of its base composition Project: MM06
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memorandum of understanding written agreement(s) to provide cooperation between two agencies or entities during a disaster incident; synonymous with “letter of concurrence” Project: GP36 NOTE 1: Memoranda of understanding are generally prepared between stakeholders who otherwise do not have a contractual relationship, to provide assistance in mitigating or responding to emergency operations; EXAMPLE: A memorandum of understanding between a local public health department and a health system to provide clinic space as part of a mass vaccination plan; NOTE 2: Memoranda of understanding between relief, public service, medical, and other organizations are implemented and updated regularly to ensure a coordinated response to a disaster in the community.
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mentoring developmental partnership through which one person shares knowledge, skills, information, and perspective to foster the personal and professional growth of someone else Project: QMS16 NOTE: This involves the practice of assigning junior personnel to the care of more experienced persons who assist them in their career.
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mesotier represents interoperability within a health care organization like a hospital, in which data and information are exchanged between an electronic health record and other information management systems, such as those used in medical laboratories, pharmacies, food services, facility management, and patient administration (admission/discharge/transfer); all data exchanged within one facility Project: AUTO17
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message the body of text information concerning orders for, or results of, diagnostic studies, tests, or clinical observations transmitted at one time between two systems Project: AUTO01, AUTO02, AUTO03
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message a textual body of information consisting of a header (H) record through a message terminator (L) record Project: LIS02
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message a collection of related information on a single topic, used to mean all the identity, tests, and comments sent at one time Project: LIS01 NOTE: When used with CLSI/NCCLS document LIS2, this term means a record as defined by CLSI/NCCLS document LIS2.
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meta-analysis 1) a statistical synthesis of the data from separate but similar (ie, comparable) studies, leading to a quantitative summary of the pooled results; 2) in the biomedical sciences, the systematic, organized, and structured evaluation of a problem of interest, using information (commonly in the form of statistical tables or other data) from a number of independent studies of the problem; 3) a statistical procedure to combine results from different studies on a similar topic Project: GP45 NOTE 1: A frequent application has been the pooling of results from a set of randomized controlled trials, none in itself necessarily powerful enough to demonstrate statistically significant differences, but in aggregate capable of so doing; NOTE 2: Meta-analysis has a qualitative component, ie, application of predetermined criteria of quality (eg, completeness of data, absence of biases), and a quantitative component, ie, integration of the numerical information. The aim is to integrate the findings, pool the data, and identify the overall trend of results; NOTE 3: An essential prerequisite is that the studies must stand up to critical appraisal, and allowance must be made for various biases (eg, publication bias); NOTE 4: The combination of results from multiple studies may produce a stronger conclusion than can be provided by any singular study; NOTE 5: Meta-analysis is generally most appropriate when there are not definitive studies on a topic and nondefinitive studies are in some disagreement.
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metabolic products short-chain fatty acids exuded by many anaerobes after a fermentation process has occurred Project: M56 NOTE: Also referred to as fermentation products.
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metabolomics the process of defining the metabolome Project: C50 NOTE 1: The metabolome consists of all metabolites in an organism; NOTE 2: The word “metabolomics” should not be used to describe the analysis of a few structurally related components.
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metadata a set of data that describes and gives information about other data Project: MM24
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metadata for the purposes of QMS26, data describing context, content, and structure of records and their management through time (modified from ISO 15489) Project: QMS26
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metagenomics the use of genomic analysis methods to identify the microbial composition of a sample, without previous isolation and propagation of each microbial component Project: MM09
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methemoglobin a dyshemoglobin (hemoglobin molecule) in which the iron is in the oxidized, ferric state (Cf. C25). See hemoglobin Alternate Term: hemiglobin, ferrihemoglobin, MetHb, Hi Project: C25
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method comparison evaluation of bias or systematic difference between two quantitative tests or evaluation of agreements between results of two qualitative tests Project: EP39
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method of measurement logical sequence of operations, described generically, used in the performance of measurements (ISO 17511) Project: ISO 17511 NOTE 1: Methods of measurement may be qualified in various ways such as: substitution measurement method; differential measurement method, and null measurement method; or direct measurement method and indirect measurement method (JCGM 200:2012); NOTE 2: A method of measurement, due to its generalized description, does not have numerically specified performance characteristics. A given method can be the basis of one or more measurement procedures, each with inherent numerical values for its performance characteristics (ISO 17511).
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method of measurement See measurement method Project: EP15
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methodologic error a problem in a diagnostic test system, kit, or manual method including inadequate reagent performance, inappropriate quality control procedures, carry-over, poor sensitivity or specificity, or erroneous calibration
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methods-based validation confirmation that specified requirements are adequate for a particular analytical method’s intended use Project: MM09
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method-specific bias systematic error due to the characteristics and properties of the measurement procedure Project: C56
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method-specific difference systematic error due to the characteristics and properties of the measurement procedure Project: EP07
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metric standard used for measurement; an evaluation method Project: QMS12
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metrological comparability of measurement results comparability of measurement results, for quantities of a given kind, that are metrologically traceable to the same reference (JCGM 200:2008) Alternate Term: metrological comparability Project: ISO IEC Guide 99 EXAMPLE: Measurement results, for the distances between the Earth and the Moon, and between Paris and London, are metrologically comparable when they are both metrologically traceable to the same measurement unit, for instance the metre (JCGM 200:2012); NOTE 1: See Note 1 to 2.41 metrological traceability (JCGM 200:2012); NOTE 2: Metrological comparability of measurement results does not necessitate that the measured quantity values and associated measurement uncertainties compared be of the same order of magnitude (JCGM 200:2012).
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metrological compatibility of measurement results property of a set of measurement results for a specified measurand, such that the absolute value of the difference of any pair of measured quantityvalues from two different measurement results is smaller than some chosen multiple of the standard measurement uncertainty of that difference (JCGM 200:2008) Alternate Term: metrological compatibility Project: ISO IEC Guide 99 NOTE 1: Metrological compatibility of measurement results replaces the traditional concept of ‘staying within the error,’ as it represents the criterion for decidingwhether two measurement results refer to the same measurand or not. If in a set of measurements of a measurand, thought to be constant, a measurement result is not compatible with the others, either the measurement was not correct (eg, its measurement uncertainty was assessed as being too small) or the measured quantity changed between measurements (JCGM 200:2012); NOTE 2: Correlation between the measurements influences metrological compatibility of measurement results. If the measurements are completely uncorrelated, the standard measurement uncertainty of their difference is equal to the root mean square sum of their standard measurement uncertainties, while it is lower for positive covariance or higher for negative covariance (JCGM 200:2012).
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metrological traceability property of a measurement result whereby the result can be related to a reference through a documented unbroken chain of calibrations, each contributing to the measurement uncertainty (JCGM 200:2012) Alternate Term: metrological traceability Project: I/LA21, C40, EP21, EP32 NOTE 1: For this definition, a “reference” can be a definition of a measurement unit through its practical realization, or a measurement procedure including the measurement unit for a nonordinal quantity, or a measurement standard (JCGM 200:2012); NOTE 2: Metrological traceability requires an established calibration hierarchy (JCGM 200:2012); NOTE 3: Specification of the reference must include the time at which this reference was used in establishing the calibration hierarchy, along with any other relevant metrological information about the reference, such as when the first calibration in the calibration hierarchy was performed (JCGM 200:2012); NOTE 4: For measurements with more than one input quantity in the measurement model, each of the input quantity values should itself be metrologically traceable and the calibration hierarchy involved may form a branched structure or a network. The effort involved in establishing metrological traceability for each input quantity value should be commensurate with its relative contribution to the measurement result (JCGM 200:2012); NOTE 5: Metrological traceability of a measurement result does not ensure that the measurement uncertainty is adequate for a given purpose or that there is an absence of mistakes (JCGM 200:2012); NOTE 6: A comparison between two measurement standards may be viewed as a calibration if the comparison is used to check and, if necessary, correct the quantity value and measurement uncertainty attributed to one of the measurement standards (JCGM 200:2012); NOTE 7: The International Laboratory Accreditation Cooperation considers the elements for confirming metrological traceability to be an unbroken metrological traceability chain to an international measurement standard or a national measurement standard, a documented measurement uncertainty, a documented measurement procedure, accredited technical competence, metrological traceability to the International System of Units, and calibration intervals (see ILAC P-10:2002) (JCGM 200:2012); NOTE 8: The abbreviated term “traceability” is sometimes used to mean “metrological traceability” as well as other concepts, such as “sample traceability” or “document traceability” or “instrument traceability” or “material traceability,” where the history (“trace”) of an item is meant. Therefore, the full term of “metrological traceability” is preferred if there is any risk of confusion (JCGM 200:2012); NOTE 9: The unbroken chain of comparisons is called a “traceability chain.”
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metrological traceability property of a measurement result whereby the result can be related to a reference through a documented unbroken chain of calibrations, each contributing to the measurement uncertainty Project: C51 NOTE 1: For this definition, a “reference” can be a definition of a measurement unit through its practical realization, or a measurement procedure including the measurement unit for a nonordinal quantity, or a measurement standard; NOTE 2: Metrological traceability requires an established calibration hierarchy; NOTE 3: Metrological traceability of a measurement result does not ensure that the measurement uncertainty is adequate for a given purpose or that there is an absence of mistakes; NOTE 4: A comparison between two measurement standards may be viewed as a calibration if the comparison is used to check and, if necessary, correct the quantity value and measurement uncertainty attributed to one of the measurement standards (JCGM 200:2008 § 2.41).
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metrological traceability chain sequence of measurement standards and calibrations that is used to relate a measurement result to a reference (JCGM 200:2012) Alternate Term: traceability chain Project: ISO IEC Guide 99, MM06 NOTE 1: A metrological traceability chain is defined through a calibration hierarchy (JCGM 200:2012); NOTE 2: A metrological traceability chain is used to establish metrological traceability of a measurement result (JCGM 200:2012); NOTE 3: A comparison between two measurement standards may be viewed as a calibration if the comparison is used to check and, if necessary, correct the quantity value and measurement uncertainty attributed to one of the measurement standards (JCGM 200:2012).
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metrological traceability to a measurement unit metrological traceability where the reference is the definition of a measurement unit through its practical realization (JCGM 200:2008) Alternate Term: metrological traceability to a unit Project: ISO IEC Guide 99 NOTE: The expression "traceability to the SI" means ‘metrological traceability to a measurement unit of the International System of Units’ (JCGM 200:2012).
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metrology science of measurement and its application (JCGM 200:2012) Project: ISO IEC Guide 99 NOTE: Metrology includes all theoretical and practical aspects of measurement, whatever the measurement uncertainty and field of application (JCGM 200:2012).
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metrology science of measurement (ISO 17511) Project: ISO 17511 NOTE: Metrology includes all aspects both theoretical and practical with reference to measurements, whatever their uncertainty, and in whatever fields of science or technology they occur (ISO 17511).
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MHC Dextramer (or the equivalent) an engineered major histocompatibility complex multimer reagent comprising multiple major histocompatibility complex molecules and multiple fluorochromes attached to a dextran backbone by either covalent or noncovalent interactions. MHC Dextramers® (or the equivalent) typically have more than 10 major histocompatibility complex molecules homogenously loaded with single peptide ligands. The attached fluorochromes are typically allophycocyanine, phycoerythrin, or fluorescein isothiocyanate, but other fluorophores or labeling molecules may be used Project: I/LA26
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MIC test test that is capable of determining an MIC covering a range of at least five consecutive doubling dilutions, and for which EA can be determined (ISO 20776-2) Project: ISO 20776-2
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MIC50 the minimal inhibitory concentration required to inhibit the growth of 50% of the organisms Project: VET05, M39
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MIC90 the minimal inhibitory concentration required to inhibit the growth of 90% of the organisms Project: VET05, M39
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microarray (resequencing) a method using specific nucleotide match-mismatch probes that allows the sequence of a genomic region to be determined Project: MM22, MM24
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microarray (tiling) a method using overlapping or adjacent probes to interrogate a specific genomic sequence region Project: MM22, MM24
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microbead array suspension a suspension of microparticle beads that can be differentiated from each other by size or color Project: ILA29
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microbial aerosol suspensions of particles in air consisting partially or wholly of microorganisms that may remain suspended in the air for extended periods of time NOTE 1: Some particles (1 to 5 um) are easily drawn into the alveoli of the lungs and may be retained there; NOTE 2: See droplet nuclei.
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microbial identification system a test system that utilizes multiple substrates and/or reagents to identify aerobic or anaerobic bacteria, yeasts, moulds, or yeast-like algae grown from culture Alternate Term: MIS Project: M50
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microbicide a general term that indicates an agent that kills pathogenic microorganisms on inanimate surfaces NOTE: The term is often used in place of germicide.
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microbiological content in reagent water testing, the quantity of viable organisms, as determined by total colony count after incubation at 36 ± 1 °C for 24 hours, followed by 24 hours at ambient temperature (23 ± 3 °C) and reported as colony-forming units per milliliter (CFU/mL)
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microbiological safety cabinet (MSC) ventilated enclosure, intended to offer protection to the user and the environment from the aerosols arising from handling of potentially hazardous and hazardous microorganisms, with means for filtering air discharged to the atmosphere (ISO 15190) Alternate Term: biological safety cabinet Project: ISO 15190 NOTE: Adapted from EN 12469:2000.
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microbiome the community of microbes within a specific area of the human body Project: MM09
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microchip a protein microarray is composed of molecules of protein affixed at separate locations, in an ordered manner, on glass or other chemically suitable matrices, forming a microscopic array Alternate Term: microarray chip Project: ILA29 NOTE: These arrays are used to identify protein-protein interactions, to identify the substrates of protein kinases, or to identify the targets of biologically active small molecules. The most common protein microarray is the antibody microarray, where antibodies are spotted onto the protein chip and are used as capture molecules to detect proteins from cell lysate solutions.
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microcollection devices proprietary systems or kits with matched components that are used to simplify the processes of collection, storage, centrifugation, and separation of the blood constituents less than 1 mL in volume Project: GP39, GP34
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microcollection tube a small-volume container used to collect capillary blood specimens Project: GP42
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microdilution (in susceptibility testing methods) performance of broth dilution in microdilution trays with a capacity of ≤ 200 µL per well (ISO 20776-1) Project: ISO 20776-1
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microhaplotype two or more multiallelic nucleotides that reside close enough (eg, < 200 base pairs) to be detected within a single next-generation sequencing read Project: MM09
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microhematocrit method the determination of the packed cell volume using a small quantity of whole blood, a capillary tube, and a high-speed centrifuge Project: H07
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microorganism microbiological entity, cellular or noncellular, capable of replication or of transferring genetic material (ISO 15190) Project: ISO 15190, QMS04
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microorganism any organism that is too small to be viewed by the unaided eye, such as bacteria, viruses, molds, yeast, protozoa, and some fungi and algae Project: GP40
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microparticle as used in CLSI document I/LA24, a discrete physical body such as a biological cell or plastic bead or liquid droplet having a volume between about 1 and 10 000 cubic microns (i.e., an equivalent spherical diameter of about 1 to 30 microns) Project: I/LA24
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microparticle agglutination immunoassay See nonlabeled immunoassay Project: H59
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microphotometry the measurement of light emanating from an illuminated microscopic field Project: I/LA24
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microtier consists of the workflow management in the laboratory domain, in which various analyzer and systems generate traditional laboratory in vitro diagnostic test results that are exchanged between analyzer, middleware, and laboratory information systems Project: AUTO17
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microwave field electromagnetic, nonionizing radiation that is produced by the magnetron Project: GP28 NOTE 1: The microwave field refers to the density of microwave energy in a defined space; NOTE 2: The microwave energy density in a space is sometimes referred to as “field strength.”
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microwaves electromagnetic energy between far infrared and radio waves that corresponds to wavelengths of 1 cm to 1 m Project: GP28 NOTE: The frequency range of these sources is between 30 GHz and 300 MHz with a frequency of 2450 MHz being the most common.
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microwave-transparent having the property of transmitting microwaves, materials such as glass or plastics that do not absorb microwave energy Project: GP28
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middleware software and hardware inserted between instrument(s) and/or automation line(s) and the laboratory information system to facilitate the management of the instrument, test requests, validation of results, and reporting Project: EP23
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middleware software and hardware inserted between an instrument(s) and/or automation line(s) and the laboratory information system to facilitate management of the instrument, test requests, verification of results, and reporting Project: QMS26, AUTO15, AUTO17
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midstream clean-voided specimen a urine specimen collected using the same technique as for midstream-voided specimen with careful attention given to cleanliness of the genitalia, hands, and catch container Project: GP08
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milestone action-planning element that delineates by what date a significant event or action will be accomplished and by what criteria of success that event or action should be measured Project: QMS06
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milestone action-planning element that delineates by what date a significant event or action is to be accomplished and by what criteria of success that event or action should be measured
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Miller disc an optical micrometer or reticule that is placed into the optical light path of a microscope Project: H44 NOTE 1: It is designed as an inscribed square containing smaller inner square(s) inscribed with exactly one-ninth the area of the larger outer square. The examiner determines the ratio of one cell type (e.g., reticulocytes) to another cell type (e.g., mature erythrocytes); NOTE 2: The disc was invented by Dr. JW Miller of the National Institutes of Health (NIH).
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miller disc an optical micrometer or reticule that is placed in the optical light path of a microscope Project: H44 NOTE 1: It is designed with a large square that contains a smaller square exactly one-ninth the area of the large square (see Figure 1A in CLSI document H44); NOTE 2: Using techniques as described in Section 7.3 of CLSI document H44, the examiner determines the ratio of one cell type (eg, reticulocytes) to another cell type (eg, mature erythrocytes); NOTE 3: The disc was invented by Dr. JW Miller of the National Institutes of Health (NIH).
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millimolar absorptivity the absorbance, at a given wavelength, of an absorbing substance in a concentration of 1 (m)mol/L, measured with a sample thickness of 1.000 cm. Terms used previously are “(milli)molar absorption coefficient” and “(milli)molar extinction coefficient.” The wavelength can be shown as a superscript and the component measured as a subscript Project: H15 NOTE: In the case of HiCN, the term “quarter (milli)molar absorptivity” is usually used, 1 mol of hemoglobin being defined as the monomer, consisting of one heme group plus one globin (a or b) chain.
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millwork custom made cabinet/countertop systems Project: QMS04
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mince to cut and separate into very small pieces, usually performed using sterile scalpels Project: M54
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mincing to cut and separate into very small pieces, usually performed using sterile scalpels Project: M54
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minimal bactericidal concentration the lowest concentration of an antimicrobial agent that kills 99.9% of bacterial cells exposed to the agent after a fixed length of time in a broth dilution susceptibility test Project: M26
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minimal bactericidal concentration the minimal concentration of an antimicrobial agent needed to kill most (>99.9%) of the viable microorganisms after incubation for a fixed length of time (generally 24 hours) under a given set of conditions Project: VET02
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minimal detectable concentration the lowest concentration that can be accurately estimated by a given test system Project: I/LA21 NOTE: Sometimes this is defined as the lowest concentration that can be statistically distinguished from zero, but other definitions may be used.
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minimal effective concentration the lowest concentration of an antimicrobial agent that leads to the growth of small, rounded, compact hyphal forms as compared to the hyphal growth seen in the growth control well Project: M38, M51 NOTE: This terminology is currently used only with respect to testing of the echinocandin antifungal agents (see Appendix G in M38).
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minimal inhibitory concentration the lowest concentration of an antimicrobial agent that causes a specified reduction in visible growth of a microorganism in an agar or broth dilution susceptibility test Project: M27, M51, M38, M44 NOTE: The magnitude of reduction in visible growth is assessed using the following numerical scale: 0, optically clear; 1, slightly hazy; 2, prominent decrease (~50%) in visible growth; 3, slight reduction in visible growth; and 4, no reduction in visible growth.
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minimal inhibitory concentration the lowest concentration of an antimicrobial agent that prevents visible growth of a microorganism in an agar or broth dilution susceptibility test Project: VET01, M26, M24, M23, M11, M06, M45, VET02, M43, M52, M57, M02, M07, VET09 NOTE: For some organism-antimicrobial-test combinations, alternative definitions are sometimes recommended as more appropriate (eg, 80% reduction in growth compared with antimicrobial agent–free controls).
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minimal inhibitory concentration the lowest concentration of an antimicrobial agent that prevents visible growth (or a growth reduction of greater than or equal to 80%) of a microorganism in an agar or broth dilution susceptibility test Project: VET04
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minimal inhibitory concentration the lowest concentration of an antimicrobial agent that prevents visible growth (or a growth reduction of greater than or equal to 80% in the case of sulfonamide-type drugs) of a microorganism in an agar or broth dilution susceptibility test Project: VET05
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minimal lethal concentration the lowest concentration of an antimicrobial agent that kills a defined proportion of bacterial or fungal cells exposed to the agent after a fixed length of time in a broth dilution susceptibility test Project: M26
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Minimal Lower Layer Protocol the most common mechanism for sending unencrypted HL7® messages by transmission control protocol/Internet protocol over a local area network, such as those found in a hospital Project: AUTO16
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minimal residual disease small numbers of leukemic cells that remain in the patient during treatment, or after treatment when the patient is in remission (with no accompanying symptoms or signs of disease); it is the major cause of relapse in cancer and leukemia Project: MM19 NOTE 1: Polymerase chain reaction–based assays can measure minute levels of cancer cells in tissue samples, sometimes as low as one cancer cell in one million normal cells; NOTE 2: In cancer treatment, particularly leukemia, minimal residual disease testing has several important roles: determining whether treatment has eradicated the cancer or whether traces remain, comparing the efficacy of different treatments, monitoring patient remission status and recurrence of the leukemia or cancer, and choosing the treatment that will best meet those needs (personalization of treatment).
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minimum inhibitory concentration (MIC) lowest concentration that, under defined in vitro conditions, prevents visible growth of bacteria within a defined period of time (ISO 20776-1) Project: ISO 20776-1, ISO 20776-2 NOTE: The MIC is expressed in mg/L (ISO 20776-1).
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minor allergen generally regarded as an allergenic molecule to which < 50% of clinically allergic patients with an allergy to its source react Project: I/LA20
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minor discrepancy (mD) test result by the reference method interpreted as R or S and an AST device result of I; or a reference result interpreted as I and an AST device result of R or S. Another representation of the concept: NmD × 100/N where NmD is the number of tests that result in an mD; N is the total number of bacterial isolates tested (ISO 20776-2) Project: ISO 20776-2 NOTE: The overall mD is expressed as a percentage (ISO 20776-2).
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minor discrepancy discrepancy in a test result between a new antimicrobial susceptibility testing system and the comparator method result (from an existing commercial antimicrobial susceptibility testing system) where one result is intermediate and the other is susceptible or resistant; see the following equation: % mD = NmD • 100/NT Project: M52 NOTE 1: NT is the total number of isolates tested; NOTE 2: “Discrepancy” is used in this document when two systems are in disagreement, while “error” is used when the antimicrobial susceptibility testing system result does not agree with the reference method result.
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minor error difference in test results between a new antimicrobial susceptibility testing system and reference antimicrobial susceptibility test result where one result is intermediate and the other is susceptible or resistant; see the following equation: % mE = NmE • 100/NT Project: M52 NOTE 1: NT is the total number of isolates tested; NOTE 2: “Discrepancy” is used in this document when two systems are in disagreement, while “error” is used when the antimicrobial susceptibility testing system result does not agree with the reference method result.
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miracidium free-living, ciliated larva released from a trematode egg and infective for the snail intermediate host Project: M28
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mismatch hybridization of two DNA or RNA strands that are less than 100% complementary Project: MM10, MM12
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mismatch a nucleotide at a distinct position within an alignment that is different between at least two aligned sequences Project: MM18
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mismatch situation in which one or more nucleotides in the same position of two otherwise identical DNA or RNA molecules are not the same. An example is an alignment of DNA sequences from two individuals including a polymorphic nucleotide (ie, an SNP) that differs between the individuals. Project: MM01
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mismatch a base pair difference between two nucleic acid sequences that renders them less than 100% complementary Project: MM22, MM24 NOTE: See also single-nucleotide polymorphism.
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missed detection rate percentage of occasions when the reference blood glucose level reached the alert setting but the continuous glucose monitoring system did not initiate an alert within a prespecified time window before or after the blood glucose reached the alert setting Project: POCT05
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missense variant a single DNA base substitution resulting in a codon specifying a different amino acid Project: MM01, NBS09
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mission an element of the organization-wide direction phase of plans management that delineates a broad strategy to meet the paramount current customer needs with the managerial and operational resources of today
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mitigation an action to lower or eliminate the risk associated with an adverse situation or to prevent the occurrence of future errors Project: EP23
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mitigation measures instituted before an incident, which are intended to reduce its likelihood or effect Project: GP36 EXAMPLES: Strategically stationed evacuation sleds on hospital floors to permit emergency vertical (floor-to-floor) patient evacuations; dikes to contain flooding and its effects.
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mitochondrial DNA the DNA in the circular chromosome of the mitochondria. Mitochondrial DNA is present in many copies per cell, is maternally inherited, and evolves five to 10 times more rapidly than genomic DNA
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mitogen a substance that triggers cellular pathways to induce mitosis and proliferation Project: NBS06 NOTE: Proliferative responses of lymphocytes to mitogens are part of the diagnostic evaluation for suspected severe combined immunodeficiency.
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mixed agglutination test a test that uses as an endpoint the aggregation that results from the reaction of antibody with similar antigenic determinants on two different types of particles (or cell types) Project: DI01
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mixing the process by which items are combined or united into one mass Project: H60 NOTE: The net effect of the process is to make the item(s) thinner or more liquid by admixture with something; for example, the process of mixing a patient plasma with normal pooled plasma results in dilution of each of the components.
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mobile medical unit a movable or detached self-contained health care facility within or from which health care services can be provided Project: POCT16
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mobile phase the flow stream that is used to carry the specimen extract into the mass spectrometer Project: NBS04, NBS09
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modal MIC/MEC the most frequent minimal inhibitory concentration or minimal effective concentration found within an minimal inhibitory concentration or minimal effective concentration distribution Project: M51
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mode a specific manner of operation of a device
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mode the value(s) of a random variable at a local maximum of the probability mass function of a discrete random variable, or at a local maximum of the probability density function of a continuous random variable (ISO3534-1/93-1.17) Alternate Term: average Project: ISO3534-1/93-1.17
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mode the most frequent value of a random variable (ASQC3-74) at a local maximum of the probability function/distribution Alternate Term: average Project: ISO3534-1/93-1.17
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mode stirrer a device that disrupts standing microwave patterns and distributes the microwave energy more homogeneously throughout a microwave cavity Project: GP28
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model simplified description or graphic containing the essential structure of a more complex system or process Project: QMS14
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model See measurement model Alternate Term: measurement model; model of measurement Project: C51
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model of measurement See measurement model. Alternate Term: measurement model; model Project: C51
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modified carbapenem inactivation method phenotypic assay for detecting carbapenemase production in which the ability of an isolate to degrade meropenem in a 10-µg disk is assessed Project: M02, M07, VET01
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modified MIS a test system in which the user has modified the manufacturer’s instructions including but not limited to use of required reagents/accessories, adherence to test instructions and conditions, and intended use Project: M50
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modular casework system prefabricated casework that comes in standard-sized modules Project: QMS04 NOTE: This can be a fixed system or a flexible system.
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molar F/P ratio the molarity of fluorochrome per mole of fluorochrome-ligand conjugate (FLC) Project: I/LA24 NOTE: the ratio is equivalent to the average number of molecules of fluorochrome per molecule of FLC.
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molar quantity See Quantity Project: I/LA24
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mole the amount of a substance containing 6.023x1023 basic relatively homogenous units (eg, atoms, molecules, cells, or particles) of that substance Project: I/LA24
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molecular bar code a short sequence of deoxynucleotides that can serve as a unique marker for tracking material from a given source through multiplex processing Project: MM09
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molecules of equivalent soluble fluorochrome (MESF) the number of native (unconjugated) fluorochrome molecules in solution that gives the same fluorescence yield as a solution of fluorochrome conjugated to other molecules or a suspension of fluorochrome bound to microspheres or cells Project: I/LA24
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molecules of equivalent soluble fluorochrome a sample labeled with a fluorophore has the same fluorescence intensity as an equivalent number of molecules of the free fluorochrome in a solution under the same environmental conditions Project: H62
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moniliform having constrictions, resembling a string of beads or bead-like swelling
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monitor to observe, record, or detect directly, or with instruments, in a manner that has minimal effect on the phenomenon assessed Project: I16 NOTE: Generally connotes continuous or frequent intermittent observations.
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monitoring process of constant evaluation of a state or condition Project: ISO 15196
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monitoring the continuous routine measurement and analysis of antimicrobial susceptibility testing information to detect trends Project: VET05
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monitoring system a system intended for the quantitative measurement of blood glucose as an aid to monitor the effectiveness of glycemic control Project: POCT06
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monoclonal arising from a single clone of B lymphocytes or plasma cells Project: ILA18 NOTE: All molecules of a monoclonal antibody have a single class and subclass of both heavy and light immunoglobulin chains, and a single antigenic-determinant specificity.
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monoclonal a cell population or product arising from a single clone of cells Project: I/LA28 NOTE: All molecules of a monoclonal antibody have a single class and subclass of both heavy and light immunoglobulin chains, and a single antigenic determinant specificity.
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monoclonal antibody antibody capable of reacting specifically with a single epitope of a certain immunogenic substance (ISO 19001) Project: ISO 19001
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monoisotopic mass the mass of molecule when calculated on the basis of the most abundant isotope of each element Project: C50
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monolayered cell culture in vitro culture consisting of a single layer of cells (epithelial-like or fibroblast) that are adherent to the surface of a culture vessel Project: M41 NOTE: The degree of monolayer confluence refers to the percentage of the culture vessel’s growth surface that is populated with cells. For example, 50% confluence would indicate that the viable adherent cells of the developing monolayer occupy approximately half of the growth surface area. A monolayer at 100% confluence is one in which a sheet of contiguous cells covers the entire growth surface.
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monolithic formed from or composed of a single material; seamless Project: QMS04
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monophyletic (of a group of organisms) describes all the descendants of a given evolutionary ancestor, along with their last common ancestor (also called clade) Project: MM24
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monospecificity the immunoreactivity of an antibody and/or antiserum with only its designated antigen or antigenic determinant Project: DI01, I/LA18
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morphology the form and structure of an organism, organ, or part Project: POL1/2
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mosaicism condition in which an individual harbors two or more genetically distinct cell lines, resulting from a genetic change after formation of a zygote (ie, a postzygotic event) Project: MM17, MM09, MM21 NOTE: Occurs when an organism has two or more different populations of genetically related cells.
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movement diagram graphic illustration of a laboratory block plan that shows how samples, staff, waste, supplies, and visitors may move through the space Project: QMS04
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MSA an Health Level Seven abbreviation for message acknowledgment segment (HL7 V2.6) Project: AUTO01, AUTO02, AUTO03
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MSH an Health Level Seven abbreviation for message header segment (HL7 V2.6) Project: AUTO01, AUTO02, AUTO03
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mucoraceous related to molds of the order Mucorales (eg, Rhizopus, Mucor) Project: M54
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muda any activity that consumes resources without creating value for the customer
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multianalyte assays with algorithmic analyses algorithm of combined results from two or more biochemical or molecular markers, along with patient demographics and medical information, to generate diagnostic, prognostic, or predictive information for a disease Project: EP19
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multiantigen refers to HLA antibody test system in which all the Class I or Class II HLA antigens found on a single cell are isolated and attached to the solid phase support Project: ILA29
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multidrug resistant see multidrug-resistant organism
Project: M39
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multidrug-resistant organism an organism resistant to multiple classes of antimicrobial agents
Project: M39 NOTE 1: A multidrug-resistant organism can be further characterized as multidrug resistant, extensively drug resistant (ie, resistant to almost all classes of antimicrobial agents), or pandrug resistant (ie, resistant to all classes of antimicrobial agents); NOTE 2: These definitions are based on published global recommendations, but they can be modified by a particular facility.
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multidrug-resistant tuberculosis Mycobacterium tuberculosis isolate that is resistant to at least rifampin and isoniazid Project: M48
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multifacility antibiogram a report generated by aggregating cumulative antimicrobial susceptibility test data from more than one health care facility
Project: M39
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multihazardous waste waste that contains any combination of hazardous chemicals, radioactive materials, or biohazardous agents; low-level mixed waste – a subset of multihazardous wastes that contains both low-level radioactive waste and chemicals regulated by the Environmental Protection Agency or states as hazardous wastes Project: GP05, QMS28
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multiple (sequence) alignment the alignment of three or more sequences with gaps inserted in the sequences such that residues with common structural positions and/or ancestral residues are aligned in the same column. A consensus sequence can be built from a multiple alignment Project: MM18 NOTE: Clustal W is one of the most widely used multiple sequence alignment programs.
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multiple chronic diseases the presence of an index disease and one or more diseases or conditions with a duration of months to years in a patient, which can be linked to classification systems (eg, International Statistical Classification of Diseases and Related Health Problems, Diagnostic and Statistical Manual of Mental Disorders, and International Classification of Primary Care) Project: POCT16
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multiple comparisons the performance of multiple analyses on the same data Project: GP45 NOTE: Multiple statistical comparisons increase the probability of making a Type I error (ie, attributing a difference to an intervention when chance is the more likely explanation).
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multiple isolates isolates of the same species recovered from separate cultures, regardless of body site, specimen type, or antimicrobial susceptibility profile, obtained from a given patient during a defined time period Project: M39
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multiple linear regression attempts to model the relationship between two or more independent or explanatory variables and a dependent or response (Y) variable by fitting a linear equation to observed data Project: EP10 NOTE: The model is: Y = B0 + B1 · x1+ B2 · x2 + ... + Bk · xk where: Y is the predicted value of the dependent variable, for a particular set of values of explanatory variables, x1, x2, ..., xk.; B0 is a constant term (the "intercept" value of Y when all the x’s are zero).
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multiple of a unit measurement unit obtained by multiplying a givenmeasurement unit by an integer greater than one (JCGM 200:2008) Project: ISO IEC Guide 99 EXAMPLE 1: The kilometre is a decimal multiple of themetre (JCGM 200:2012); EXAMPLE 2: The hour is a nondecimal multiple of the second (JCGM 200:2012); NOTE 1: SI prefixes for decimal multiples of SI base units and SI derived units are given in Note 5 of 1.16 (JCGM 200:2012); NOTE 2: SI prefixes refer strictly to powers of 10, and should not be used for powers of 2. For example, 1 kilobit should not be used to represent 1024 bits (210 bits), which is 1 kibibit. Prefixes for binary multiples are (JCGM 200:2012):
| Factor | Prefix | | Name | Symbol | | (210)8 (210)7 (210)6 (210)5 (210)4 (210)3 (210)2 (210)1 | yobi zebi exbi pebi tebi gibi mebi kibi | Yi Zi Ei Pi Ti Gi Mi Ki |
Source: IEC 80000-13
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multiple of a unit (of measurement) larger unit of measurement that is formed from a given unit according to scaling conventions; EXAMPLES: a) one of the decimal multiples of the metre is the kilometre;b) one of the non-decimal multiples of the second is the hour
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multiple of the median the value of a screening marker in unaffected pregnancies of the same gestational age measured in the same laboratory (or in the case of ultrasound measurements at the same center or by the same sonographer) Project: I/LA25 NOTE: It is the observed marker concentration divided by the expected concentration where the expected is the median. The median is often calculated using measurements from all pregnancies (not just unaffected pregnancies); this makes little or no difference to estimating the multiple of the median value because affected pregnancies are rare and, therefore, have little or no influence on the median. The multiple of the median allows for the change in concentrations of the serum markers with gestation and from center to center.
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multiple reaction monitoring mode of operation for a tandem mass spectrometer in which one or several precursor(s) to product transition(s) is monitored Project: C63
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multiplex refers to a system that identifies multiple analytes in a single tube, well, chip, etc Project: ILA29
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multiplex a term applied to a process that incorporates multiple activities occurring simultaneously (eg, simultaneous detection of two or more nucleic acid targets in a single reaction) Project: MM17, MM09
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multiplex simultaneous detection of two or more nucleic acid targets in a single reaction Project: MM03, M55, MM22, MM24
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multiplex assay the simultaneous quantitative or qualitative analysis of multiple analytes Project: NBS06, NBS07, NBS09
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multiplex assay a test delivering more than one test result based on a single addition of a test specimen Project: I/LA20 NOTE: Multiplex assays can be discriminated from singleplex assays where one addition of a specimen results in immunoglobulin E antibody measurement to one allergen specificity. A multi-allergen screen is not a multiplex assay despite the fact that it has been shown by the manufacturer to detect immunoglobulin E antibody to each of the individual allergens in a mixture with a single serum addition. This is because the multiple allergens are in one allergen-containing reagent and the multi-allergen screen generates a single result, which defines it as a singleplex assay.
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multiplex primers polymerase chain reaction primers for more than one DNA target sequence that are combined in a single reaction Project: MM05
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multiplex test method simultaneously measures or detects multiple analytes in a single experiment Project: EP19
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multiplexed assay a test delivering more than one test result based on a single addition of a test specimen Project: I/LA34 NOTE: Multiplex assays can be discriminated from singleplex assays where one addition of a specimen results in immunoglobulin E antibody measurement to one allergen specificity. A multiallergen screen that involves multiple allergens in one allergen-containing reagent generates a single result, and thus should be considered a singleplex assay.
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multivalent the presence of multiple (>2) binding sites of the same structure within a molecule Project: I/LA28 NOTE: The presence of multiple binding sites by secondary antibodies increases the signal amplification obtainable.
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muriform having horizontal and vertical septa Project: M54
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mutation an alteration in the DNA sequence Project: MM22 NOTE: The molecular and clinical consequences may not be established and could range from having no consequences to deleterious or beneficial consequences.
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mutations changes in the genetic code (ie, DNA or RNA) of an organism Project: MM10
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MUXF3 Bromelain is a glycoprotein extracted from pineapple, which has been used for checking the cross-reactivity between a glycan and other glycoproteins. Its carbohydrate epitope MUXF3 is found in many plant proteins; however, a true allergy to bromelain is rare. MUXF3 is a carbohydrate digested from bromelain that is used as a reagent that contains the carbohydrate epitope and thus avoids the detection of IgE antibody binding to other bromelain epitopes
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Mycobacterium avium complex (MAC) includes the species M. avium (subspecies avium, colombiense, silvaticum, hominissuis, paratuberculosis) and Mycobacterium intracellulare
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Mycobacterium tuberculosis complex includes the species M. tuberculosis, Mycobacterium bovis, M. bovis BCG, Mycobacterium caprae, Mycobacterium pinnipedii, Mycobacterium africanum, Mycobacterium microti, and Mycobacterium canettii
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Mycobacterium tuberculosis complex group of very closely related, slowly growing mycobacterial species that infect mammals including humans and, as such, belong to a genetically related taxonomic complex Project: M48
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national disaster medical system (NDMS) a cooperative asset-sharing program among Federal government agencies, state and local governments, and the private businesses and civilian volunteers to ensure resources are available to provide medical services following a disaster that overwhelms the local healthcare resources
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national measurement standard measurement standard recognized by national authority to serve in a state or economy as the basis for assigning quantity values to other measurement standards for the kind of quantity concerned (JCGM 200:2008) Alternate Term: national standard Project: ISO IEC Guide 99
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national measurement standard standard recognized by a national decision to serve, in a country, as the basis for assigning values to other standards of the quantity concerned (VIM93) Project: VIM93
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native allergenic molecules allergenic proteins, glycoproteins, and lipoproteins that have been purified by chemical, chromatographic, electrophoretic and/or immunoaffinity techniques from allergen extracts of natural biological materials and that can elicit an immunoglobulin E antibody response Project: I/LA20
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native matrix matrix that has undergone minimal preexamination alteration after collection through a standard collection process Project: C64
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native whole blood blood withdrawn into a syringe or tube to which no additives, such as anticoagulants, are added Project: POCT14
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NCCLS former name of the Clinical and Laboartory Standards Institute
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near miss an incident where no injury, ill health, or fatality occurs (BS OHSAS 18001) Project: M29 NOTE: An event where an incident is avoided (a “close call”) and which could result in an incident occurring if not fully investigated and corrected.
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near-miss used to describe any process variation that did not affect an outcome, but for which a recurrence carries a significant chance of a serious adverse outcome NOTE: Such a “near-miss” falls within the scope of the definition of a sentinel event, but outside the scope of those sentinel events that are subject to review by the Joint Commission under its Sentinel Event Policy.
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near-patient testing NPT another term used to refer to point-of-care testing NOTE: May employ the use of noninstrumented or instrumented testing. In some cases, this may be effected in a small laboratory separate and distinct (satellite laboratory) from the main laboratory using less portable instrumentation.
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near-patient testing See point-of-care testing Alternate Term: point-of-care testing; bedside testing Project: POCT13
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neat plasma platelet-poor plasma that has not been altered, eg, diluted with normal pooled plasma or saline Project: H60
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needleless system a device that does not use needles for: i) the collection of bodily fluids or withdrawal of body fluids after initial venous or arterial access is established; ii) the administration of medication or fluids; or iii) any other procedure involving the potential for occupational exposure to bloodborne pathogens due to percutaneous injuries from contaminated sharps Project: X3-R
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negative control (NC) a sample/mock sample that should yield a negative result, because it lacks the analyte under test Alternate Term: NC Project: ILA29 NOTE: It is a method check for contamination of the reagents or artifacts that might give a false-positive result.
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negative cutoff the quantitative value of a measured analyte that is used to determine that a result is below a clinical or analytical decision point and therefore negative Project: ILA29
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negative likelihood ratio the ratio between the probability that the test will be negative when the reference standard (gold standard) is positive and the probability that the test will be negative when the reference standard (gold standard) is negative NOTE: Negative likelihood ratio tells how many times less likely the subjects with the target condition are to have a negative result than subjects without the target condition. (The ratio of the false-negative rate to the specificity [(1-sensitivity)/specificity] when there is a gold standard value.)
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negative percent agreement the test method’s ability to obtain negative results in concordance with negative results obtained by the comparative method, expressed as percentage of agreement Project: MM17, MM09 NOTE: The proportion of correct calls by the assay for the absence of a measurand.
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negative percent agreement the proportion of comparative method negative results in which the test method result is negative when the comparative method is not a widely accepted best method of assessing a target condition Project: EP19, EP12
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negative percent agreement the percentage of agreement of the test method’s ability to obtain negative results in concordance with negative results obtained by the comparative method Project: MM01 NOTE 1: The proportion of correct calls by the assay for the absence of a measurand; NOTE 2: The test method’s ability to obtain negative results in concordance with negative results obtained by the comparative method.
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negative percent agreement concordance compared with negative results from a comparator assay (nondiagnostic) Project: H62
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negative predictive value the proportion of patients with negative test results who do not have the target condition (as determined by the reference standard) Project: MM17, MM09 NOTE 1: Negative predictive value must be interpreted in context of the prevalence of the condition of interest (as determined by the reference standard); NOTE 2: An estimate of negative predictive value is calculated as 100 • true negatives / (true negatives + false negatives); NOTE 3: The rarer the abnormality, disease, or condition, the surer one can be that a negative result indicates no abnormality, while the less sure one can be that a positive result indicates an abnormality.
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negative predictive value in the context of this guideline, the likelihood that an individual with a quantitative assay result, below one or more defined thresholds, does not have a disease, is not at risk for a disease or at risk for a specific characteristic or outcome that the test is designed to detect Project: MM06 NOTE: Negative predictive value = total negative results / (true-negative results + false-negative results).
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negative predictive value the probability that a negative test result represents health Project: H20 NOTE: It is the fraction of true negative results over all negative results (true negatives/true negatives + false negatives).
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negative predictive value the chance that the patient really does not have the condition or disorder if the test result is negative. Negative predictive value = true negatives/(true negatives + false negatives) Project: H62 NOTE 1: Alternative term is predictive value of a negative result; NOTE 2: Percentage (number fraction multiplied by 100) of subjects with a negative test result who do not have the target condition (as determined by the diagnostic accuracy criteria); NOTE 3: Predictive value of a negative result must be interpreted in context with the prevalence of the condition of interest (as determined by the diagnostic accuracy criteria); NOTE 4: An estimate of predictive value of a negative result [with estimated prevalence equal to 100 × (TP + FN)/(TP + FP + FN + TN)] is calculated as 100 × TN/(TN + FN).
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negative predictive value the likelihood that an individual with a negative test result does not have the disease or other characteristic that the test is designed to detect Project: H59, MM01, MM22, MM23, MM12, I/LA21, I/LA23, POCT15 NOTE 1: The negative predictive value varies with the prevalence of the disease in the population tested; NOTE 2: From predictive value theory, the proportion of all negative tests that are true negatives; NOTE 3: The negative predictive value varies with prevalence of the disease unless the test is 100% sensitive or specific; NOTE 4: Negative predictive value = true negative / (true negative + false negative).
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negative pressure room pressure below that of an adjacent space, causing air to flow into the room from the adjacent space Project: QMS04
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negative result a result indicating a sample is devoid of the test measurand or the result is below the cutoff value or the lower limit of detection, as applicable Project: C52, C63
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negative screen result a screen result within the expected range of results that defines unaffected individuals for a particular disorder Project: NBS05 NOTE: A negative screen result is also referred to as a “negative,” “negative screen,” “screen negative,” “negative test result,” “negative screening test result,” “presumptive negative result,” “normal result,” or “in-range result.”
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neighbor joining a relatively simple and rapid method for reconstructing phylogenetic trees from an evolutionary distance matrix Project: MM18 NOTE 1: Other methods such as maximum parsimony or maximum likelihood are more accurate for determining an evolutionary relationship but necessitate more computing time; NOTE 2: Usually used for phylogenetic trees based on DNA or protein sequence data.
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neonatal of or pertaining to newborn children
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neonatal intensive care unit hospital facility or unit staffed and equipped to support babies born at < 32 weeks gestation and/or weighing < 1500 g and all critically ill newborns Project: NBS03 NOTE: See also special care baby unit.
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neonatologist a pediatrician with specialized training and certification in the care of newborns who need intensive care Project: NBS03
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Nernst Equation the expression which relates electromotive force (potential difference) of an electrochemical cell to the activity of chemical species in solution Project: C39
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nested in the design of a multifactor study, the effects of a factor A are said to be nested within the effects of a factor B if each effect of factor A occurs with only one effect of factor B Project: EP05 EXAMPLE: Replicates within a run are distinct from replicates within another run, thus replicates are nested within runs. See also crossed.
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net square footage usable square footage in a space Project: QMS04
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net-to-gross factor multiplier applied to net (usable) square feet to estimate the gross (total) square footage
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network 1) an arrangement of nodes and interconnecting branches; 2) a system (transmission channels and supporting hardware and software) that connects several remotely located computers via telecommunications (ISO/IEC International Standard 812) Project: AUTO08
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network infrastructure and components (hardware and software) for passing computerized, digital data Project: POCT02 NOTE: Examples include a hospital’s local area network for communicating within the institution, externally to a regional wide area network or more globally to the worldwide Internet.
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Network Address Translation method by which Internet Protocol addresses are mapped from one group to another, transparent to end users (RFC 3022) Project: AUTO09
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Network Time Protocol principal time synchronization and distribution protocol used on the Internet (RFC-1305) Project: POCT01 NOTE: Network Time Protocol provides robust, reliable, and highly accurate time synchronization using algorithms and protocols that utilize a hierarchical network of time servers and clients that are ultimately tied to one or more primary time servers connected to external times sources, such as a GPS radio clock or automated computer time service telephone modem time service.
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neutral loss scan the data acquisition mode for tandem mass spectrometry in which both mass analyzers are scanned such that the difference between the mass analyzers is set at a known neutral loss (such as 102 Da for analysis of amino acid butyl esters) Project: NBS04, NBS09
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neutralizing antibodies result in inactivation of the factor Project: H48
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newborn blood spot screening algorithm the logic process comprising the set of tests and follow-up evaluations used to identify newborns who will be referred for diagnostic evaluation and/or treatment Project: NBS07 NOTE: The overall newborn blood spot screening algorithm includes both the laboratory screening and follow-up algorithms.
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newborn dried blood spot screening process of collecting blood onto the blood collection (specified filter paper) section of a specimen collection device (for newborn screening), testing defined analytes by approved laboratory methods, and reporting results as appropriate Project: NBS02, NBS03, NBS13, NBS10 Source: Newborn Screening Glossary
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newborn hearing screening the process of using a physiological measure of auditory function to detect hearing differences present in the newborn period that might interfere with the development of speech and language Project: NBS02, NBS03 Source: Newborn Screening Glossary
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newborn screening algorithm the logic process composed of the set of tests and follow-up evaluations used to identify newborns who will be referred for diagnostic evaluation and/or treatment Project: NBS06 NOTE: The overall newborn screening algorithm includes both the laboratory screening and the follow-up algorithms.
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newborn screening program a health program, which is one part of a greater newborn screening system, that operates with the goal of reducing morbidity and mortality in newborns with congenital diseases through early detection and intervention and consists of the jurisdiction’s health service components, which might include policies and regulations, planning and audits, specimen collection and transport, laboratory testing, and short- and long-term follow-up Project: NBS03, NBS01, NBS02, NBS13, NBS05, NBS09, NBS06, NBS07, NBS10 Source: Newborn Screening Glossary NOTE 1: In some jurisdictions, an entity is responsible for coordinating the health program elements essential to ensuring optimal health outcomes for screened newborns; NOTE 2: Newborn screening can be laboratory based or point of care based; NOTE 3: Most laboratory-based newborn screening uses dried blood spot specimens collected from heelsticks and analyzed by centralized laboratories that serve a region or jurisdiction; NOTE 4: See newborn screening system and newborn dried blood spot screening.
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newborn screening system a collaboration of newborn screening stakeholders, including public and private agencies, organizations, families, policy makers, health care providers, and other caregivers, working together to ensure that all newborns within a defined geographical area have access to newborn screening and that babies found affected are able to access appropriate care and optimize health outcomes Project: NBS01, NBS02, NBS03, NBS13, NBS09, NBS05, NBS06, NBS07, NBS10 Source: Newborn Screening Glossary NOTE: See newborn screening program.
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newdemic an unexpected and disruptive problem that affects the health of large numbers of individuals in a crowded world Project: POCT16
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next-generation sequencing DNA sequencing, encompassing several high-throughput approaches, that uses miniaturized and parallelized platforms for sequencing of thousands to millions of short reads (≈ 50 to 400 bases) Alternate Term: second-generation sequencing Project: MM09, MM26 NOTE: Also known as second-generation sequencing.
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ninety-degree light scatter light reflected at right angles to the incident light source Alternate Term: orthogonal light scatter; right-angle light scatter (side-scatter light//wide-scatter light) Project: H42 NOTE: This measurement is related to cytoplasmic granularity and/or membrane irregularity of a cell or particle.
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NIST traceable reference material a reference material produced by a commercial supplier with a well-defined traceability linkage to the National Institute of Standards and Technology (NIST) Project: I/LA24, I/LA28 NOTE: This linkage is established via criteria and protocols defined by NIST that are tailored to meet the needs of the metrological community to be served. Reference material producers adhering to these requirements will be allowed the NIST “NTRM” trademark.
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noise unwanted background signal that may adversely affect the ability to distinguish a positive signal Project: MM18
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noise unwanted sound in the form of acoustic energy which may adversely affect health (ISO 15190) Project: ISO 15190
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noise background calls, typically of lower quality, that may adversely affect the ability to correctly call a nucleic acid sequence variant Project: MM09
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noisy CGM sensor a sensor that exhibits multiple changes in the output signal over time, not related to a change in sensitivity or glucose concentration NOTE: Noise within the output signal may be quantified by amplitude, frequency, power, and pattern.
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nomina rejicienda per the Judicial Commission of the International Committee of Systematics of Prokaryotes, a name that must not be used to designate any taxon Project: M64
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nominal property of a phenomenon, body, or substance, for which the property has no magnitude Project: H62 NOTE: See qualitative.
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nominal indication interval set of quantity values, bounded by rounded or approximate extreme indications, obtainable with a particular setting of the controls of a measuring instrument or measuring system and used to designate that setting (JCGM 200:2008) Alternate Term: nominal interval Project: ISO IEC Guide 99 NOTE 1: A nominal indication interval is usually stated as its smallest and greatest quantity values, for example, "100 V to 200 V" (JCGM 200:2012); NOTE 2: In some fields, the term is "nominal range" (JCGM 200:2012).
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nominal mass the mass of an ion calculated by adding the integer masses of the lightest isotopes of all elements contributing to a molecule Project: C50
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nominal property property of a phenomenon, body, or substance, where the property has no magnitude (JCGM 200:2012) Project: ISO IEC Guide 99, C51 EXAMPLE 1: Sex of a human being (JCGM 200:2012); EXAMPLE 2: Colour of a paint sample (JCGM 200:2012); EXAMPLE 3: Colour of a spot test in chemistry (JCGM 200:2012); EXAMPLE 4: ISO two-letter country code (JCGM 200:2012); EXAMPLE 5: Sequence of amino acids in a polypeptide (JCGM 200:2012); NOTE 1: A nominal property has a value, which can be expressed in words, by alphanumerical codes, or by other means (JCGM 200:2012); NOTE 2: ‘Nominal property value’ is not to be confused with nominal quantity value (JCGM 200:2012); EXAMPLE 6: Blood group (JCGM 200:2008 § 1.30).
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nominal quantity value rounded or approximate value of a characterizing quantity of a measuring instrument or measuring system that provides guidance for its appropriateuse (JCGM 200:2008) Alternate Term: nominal value Project: ISO IEC Guide 99 EXAMPLE 1:100 Ω as the nominal quantity valueemarked on a standard resistor (JCGM 200:2012); EXAMPLE 2: 1000 mL as the nominal quantity value marked on a single-mark volumetric flask (JCGM 200:2012); EXAMPLE 3: 0.1 mol/L as the nominal quantity value for amount-of-substance concentration of a solution of hydrogen chloride, HCl (JCGM 200:2012); EXAMPLE 4: −20 °C as a maximum Celsius temperature for storage (JCGM 200:2012); NOTE: "Nominal quantity value" and "nominal value" are not to be confused with "nominal property value" (see 1.30, Note 2) (JCGM 200:2012).
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nominal range range of indications obtainable with a particular setting of the controls of a measuring instrument NOTES
1 Nominal range is normally stated in terms of its lower and upper limits, for example, "100 oC to 200 oC". Where the lower limit is zero, the nominal range is commonly stated solely in terms of its upper limit: for example a nominal range of 0 V to 100 V is expressed as " 100 V".
2 See span, Note.
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nominal tube size description of the approximate external diameter and length of a tube in millimeters Project: GP39
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nominal value rounded or approximate value of a characteristic of a measuring instrument that provides a guide to its use; EXAMPLES: a) 100 ohm as the value marked on a standard resistor; b) 1 L as the value marked on a single-rnark volumetric flask; c) 0,1 mol/L as the amount-of-substance concentration of a solution of hydrogen chloride, HCl; d) 25 °C as the set point of a thermostatically controlled bath
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nonactivating surface a surface that minimizes activation of anticoagulated whole blood specimens/plasma samples and results in the inhibition of platelet and coagulation factor activation (as indicated by lengthening or shortening of the prothrombin time or activated partial thromboplastin time) Project: H21
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nonadjunctive continuous glucose monitoring device a device that has readings that can be directly used to guide therapy without the need to verify with a self-monitoring blood glucose test Project: POCT05
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nonclinical pharmacokinetic/pharmacodynamic cutoff the highest minimal inhibitory concentration at which efficacy would be predicted in patients based on nonclinically derived pharmacokinetic/pharmacodynamic relationships and human pharmacokinetic exposures Project: M23
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noncoding sequence components of an organism’s DNA sequences that do not contain information for protein sequences Project: MM19 NOTE: In many eukaryotes, a large percentage of an organism’s total genome size is noncoding DNA, although the amount of noncoding DNA, and the proportion of coding vs noncoding DNA, varies greatly between species. Much of this DNA has no known biological function and is sometimes referred to as “junk DNA.” However, many types of noncoding DNA sequences do have known biological functions, including the transcriptional and translational regulation of protein-coding sequences. Other noncoding sequences have likely but as yet undetermined function, an inference from high levels of homology, and conservation seen in sequences that do not encode proteins but appear to be under heavy selective pressure.
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noncognitive error error due to inadvertent or unconscious lapse in expected automatic behavior (ISO/TS 22367) Project: ISO/PDTR 22367
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noncognitive error failure to accomplish a task that is usually automatic because of a lapse in concentration NOTE: Also referred to as "slips."
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noncompetitive assay an immunoassay in which the analyte (antigen) is captured by the receptor (or first antibody), and a second labeled antibody is used to measure the amount of analyte bound or captured by the binding site Project: I/LA23
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noncompliance failure or refusal to comply, as with a law, regulation, or term of a contract Project: QMS17
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nonconformance nonfulfillment of a requirement (ISO 9000) Alternate Term: nonconformity Project: ISO 9000, QMS21 NOTE 1: Other terms frequently used include: accident, adverse event, error, event, incident, nonconformity, and occurrence; NOTE 2: This may be defined as deviation from expected outcome; NOTE 3: Different assessment organizations may have their own terminologies (eg, citation, deficiency, finding, noncompliance, or observation).
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nonconforming event an occurrence that does not conform to the laboratory’s policies, processes, and/or procedures or with applicable regulatory or accreditation requirements or has the potential to affect (or has affected) patient, donor, or personnel safety Project: QMS11, QMS01 Source: Quality Glossary
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nonconforming event (occurrence) an incident that does not conform to the service’s established policies, processes, or procedures; other terms frequently used include accident, adverse event, error, event, nonconformance, and nonconformity Project: MM20
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nonconforming event management (occurrence management) the process by which errors, or near errors (also called near misses), are identified and handled Project: MM20
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nonconformity nonfulfillment of a stated requirement, need, or expectation (modified from ISO 9000) Project: QMS24
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nonconformity See nonconformance Alternate Term: nonconformance Project: QMS21
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nonconformity nonfulfillment of a requirement (ISO 9000)
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nonfasting glucose a glucose measurement taken at any time Alternate Term: casual glucose; randomly timed glucose Project: POCT13 NOTE 1: It may be taken shortly after ingesting food or sugar-containing beverages, taking medication, or exercising; NOTE 2: In contrast, see fasting glucose.
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nonhazardous waste 1) This category includes all other clinical laboratory waste not in any of the above-mentioned categories; 2) In this guideline, nonhazardous waste includes all solid waste, sanitary sewerage, and air emissions that are not infectious, radioactive, sharps, chemically hazardous, or multihazardous Project: GP05 NOTE 1: Nonhazardous waste needs to be handled, managed, and disposed of properly; NOTE 2: Nonhazardous waste is not risk free; for example, staples can injure, talcum powder can pose an inhalation hazard if spilled, and hard plastics can cause injury if flying sharps are created when the plastic is compacted; NOTE 3: When improperly disposed of, nonhazardous waste can cause aesthetic degradation of the environment, such as litter on the beach.
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noninvasive point-of-care technology use of noninvasive body liquids, for example, saliva, tears, and urine, as the analytical matrix (eg, a novel photonic sensing material that responds to glucose concentrations in tears via diffraction of visible light, urine pregnancy test, and saliva alcohol) Project: POCT07
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nonlabeled immunoassay a type of assay that is based on agglutination, detecting soluble antigen. In this assay, microparticles (latex, polystyrene) coated with antibodies agglutinate in the presence of antigen and can be detected by turbidimetric or nephelometric techniques. This is a homogeneous assay that does not require the separation of the bound and free fractions Alternate Term: microparticle agglutination immunoassay Project: H59
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nonlinear scale scale in which each scale spacing is related to the corresponding scale interval by a coefficient of proportionality that is not constant throughout the scale NOTE Some nonlinear scales are given special names such as logarithmic scale, square-law scale.
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nonmaleficence the duty to cause no harm Project: GP45 NOTE: The principle of nonmaleficence requires that research design be scientifically sound and that the risks of the research be acceptable in relation to the likely benefits.
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nonmedical supplies for the purpose of this guideline, all materials brought into healthcare facilities that do not meet the definition of medical devices (eg, maintenance products, drywall, toys) Project: HS11
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non-neutralizing antibodies target nonfunctional epitopes and become clinically relevant if they result in accelerated clearance of the transfused clotting factor Project: H48
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nonparallelism extent to which the dose-response relationship between two materials (ie, calibrator vs unknown specimens) is not constant for the examined range of concentrations or activities Project: H48
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nonparametric statistical tests that are applied to datasets that do not exhibit normal distribution Project: MM06
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nonparametric a statistical procedure that, unlike a parametric procedure, does not assume a particular distribution
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nonparametric (statistical procedure) a “distribution-free” statistical procedure is also called nonparametric because, unlike a parametric procedure, it does not assume a particular distribution Project: EP24, EP17
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nonpurgeable organic carbon the concentration of organic carbon remaining after sparging a sample to remove inorganic carbon Project: GP40
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non-QMS processes processes that are not contained in either the QSEs or in the laboratory’s path of workflow, such as those within the finance, sales, or marketing functions
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non-read error the absence of data at the bar code reader output after an attempted read due to no code, defective code, bar code reader failure, or operator error Project: AUTO14
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nonreported result the absence of a result that occurs when the instrument system does not provide a valid result after completion of a measurement or when there is a delay in providing a result beyond the time of clinical usefulness Project: EP27
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nonselectivity reactivity of an agent in a test system to substances other than the analyte of interest Project: EP07 NOTE: Nonselectivity is usually caused by antibodies, enzymes, ionophores, or reagents binding, complexing, or reacting with substances other than the analyte.
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nonsense variant a single DNA base substitution resulting in a termination codon, which halts polypeptide chain synthesis at that codon Project: MM01
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nonspecific binding attachment not attributable to specific binding to a receptor Project: LA01, I/LA34, I/LA20 NOTE 1: Typically, nonspecific binding is defined as the background signal in an immunoassay that is derived from the nonspecific association of the signal generator with other reactants or the reaction vessel itself. The nonspecific binding of an assay plays a critical role in determining its analytical sensitivity characteristics. In immunoglobulin E antibody assays, background binding can also be affected by the total level of immunoglobulin E antibodies present in a specimen, because immunoglobulin E may also associate nonspecifically with reactants, giving a falsely high measure of specific immunoglobulin E antibody levels; NOTE 2: Typically, nonspecific binding is defined as the background signal in an immunoassay that is derived from the nonspecific association of the signal generator with other reactants or the reaction vessel itself. The nonspecific binding of an assay plays a critical role in determining its lower limit of detection and subsequently its lower limit of quantitation characteristics. In immunoglobulin E antibody assays, background binding can also be affected by the total level of immunoglobulin E antibodies present in a specimen, because immunoglobulin E may also associate nonspecifically with reactants, giving a falsely high measure of specific immunoglobulin E antibody levels.
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nonspecific inhibitors antibodies not directed against any particular factor, nature is unknown, possibly against a phospholipid-protein complex Project: H48
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nonspecificity reactivity of an agent in a test system to substances other than the analyte of interest Project: DI01, I/LA18 NOTE: Nonspecificity is usually caused by antibodies, enzymes, ionophores, or reagents biding, complexing, or reacting with substances other than the analyte.
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nonsprinklered areas without a sprinkler system for fire control Project: QMS04
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nonsterile an item that does not meet sterility standards established by the health care organization Project: PRE05
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nonsusceptible (NS) bacterial strain for which the test result exceeds the susceptible breakpoint and for which there are no established intermediate or resistant breakpoints (ISO 20776-2) Project: ISO 20776-2 NOTE: This is generally due to the lack of strains with resistance to the antimicrobial agent when the breakpoints are defined (ISO 20776-2).
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nonsusceptible a category used for organisms that currently have only a susceptible interpretive category, but not intermediate or resistant interpretive categories (ie, susceptible-only interpretive category) and is often given to new antimicrobial agents for which no resistant isolates have yet been encountered
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nonsusceptible a category used for isolates for which only a susceptible interpretive criterion has been designated because of the absence or rare occurrence of resistant strains. Isolates that have minimal inhibitory concentrations (MICs) above or zone diameters below the value indicated for the susceptible breakpoint should be reported as nonsusceptible NOTE 1: An isolate that is interpreted as nonsusceptible does not necessarily mean that the organism has a resistance mechanism. It is possible that isolates with MICs above the susceptible breakpoint that lack resistance mechanisms may be encountered within the wild-type distribution subsequent to the time the susceptible-only breakpoint is set; NOTE 2: For strains yielding results in the “nonsusceptible” category, organism identification and antimicrobial susceptibility test results should be confirmed.
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nonsusceptible antimicrobial susceptibility test interpretive category a category used for isolates for which only a susceptible interpretive criterion has been designated because of the absence or rare occurrence of resistant strains. Isolates that have minimal inhibitory concentrations above or zone diameters below the value indicated for the susceptible breakpoint should be reported as nonsusceptible Project: VET05 NOTE 1: An isolate that is interpreted as nonsusceptible does not necessarily mean that the isolate has a resistance mechanism. It is possible that isolates with minimal inhibitory concentrations above the susceptible breakpoint that lack resistance mechanisms may be encountered within the wild-type distribution subsequent to the time the susceptible-only breakpoint is set; NOTE 2: For strains yielding results in the “nonsusceptible” category, organism identification and antimicrobial susceptibility test results should be confirmed.
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nonsusceptible test interpretive category a category used for organisms that currently have only a susceptible interpretive category, but not susceptible-dose dependent, intermediate, or resistant interpretive categories (ie, susceptible-only interpretive category) NOTE: This category is often given to new antimicrobial agents for which no resistant isolates have yet been encountered.
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nonthreshold compound a compound for which detection and identification of any amount of compound is considered to be a “positive” or “present” Project: C43
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nontuberculous mycobacteria all species of mycobacteria other than Mycobacterium leprae and those in the Mycobacterium tuberculosis complex Project: M24
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nontuberculous mycobacteria descriptive term for all mycobacterial species not belonging to Mycobacterium tuberculosis complex. In general, these organisms are ubiquitous, naturally occurring organisms found in the environment (eg, water and soil), and these organisms can also be found in some domestic and wild animals Project: M48 NOTE: Outdated terms used to describe this group of mycobacteria include mycobacteria other than tuberculosis or atypical mycobacteria.
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non-wild type describes isolates with minimal inhibitory concentrations above the epidemiological cutoff value Project: VET05, VET04
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non-wild-type an epidemiological cutoff value (ECV) interpretive category defined by an ECV that describes isolates with presumed or known mechanisms of acquired resistance and reduced susceptibility for the antimicrobial (antifungal) agent being evaluated
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non-wild-type describes isolates with presumed or known mechanisms of acquired resistance and reduced susceptibility for the antifungal agent being evaluated Project: M57
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normal distribution sometimes described as Gaussian distribution, this deals with measured values on the x-axis of a curve and the frequency of the observations on the y-axis of the curve Project: H57 NOTE 1: If the observations are evenly distributed on either side of the mean, the resulting graph will have a classic bell-shaped curve; NOTE 2: When measuring different types of analytes, the curve can shift to match the trends in the observations of the data being analyzed.
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normal pooled plasma a plasma that is comprised of citrated platelet-poor plasma (with a platelet count of < 10 × 109/L) from 20 or more carefully screened male and female donors Project: H60
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normal range See reference range Alternate Term: reference range; reference interval Project: VET04
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normalization an array’s normalization is the operation of removing systematic artifacts of nonbiological origin such as variations in the sample preparation, variation in the manufacture of arrays, and in the processing of the arrays (eg, labeling efficiency, hybridization, and scanning) Project: MM16
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normalization as applied to immunohistochemistry, the process of determining bioequivalence, in vivo antigenicity, and immunoreactivity of antibody vs antigen through comparison of immunohistochemistry to Western blot, ELISA, and other platforms Project: I/LA28 NOTE: An array’s normalization is the operation of removing systematic artifacts of nonbiological origin such as variations in the sample preparation, variation in the manufacture of arrays, and in the processing of the arrays (eg, labeling efficiency, hybridization, and scanning).
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normalized ratio a ratio calculated using clotting times in seconds from an assay in the numerator and the mean of the reference interval in seconds in the denominator Project: H60
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northern blot a solid phase membrane to which RNA, transferred from a gel after electrophoresis, is bound so that it can be hybridized with a labeled nucleic acid probe Project: MM12
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nosocomial infection an infection acquired in a hospital or other health care facility that is unrelated to the patient’s or resident’s primary condition Alternate Term: health care–associated infection Project: POCT04
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no-stop a mutation that changes a termination or stop codon (TAG, TAA, or TGA) into one that codes for an amino acid
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notice a communication of information regarding the risk associated with the use of a device issued by either the manufacturer of a product, distributor, or regulator Project: HS11 NOTE: Notices may warn user facilities, healthcare professionals, users, and patients of risks.
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notification a visible or audible message delivered to the user’s display unit that is initiated by specific predefined conditions detected by the sensor and analyzed by the system algorithms Project: POCT05 NOTE: A notification is typically related to ongoing or impending adverse situations such as hypoglycemia or hyperglycemia.
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notification system process for informing personnel and responders of an emergency Project: GP36 NOTE: Systems may be manual such as a phone calling tree or automated, active or passive.
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novel type strain newly elucidated populations of cells arising from a single cell that are used as the reference phenotype for a given taxon Project: M64
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N-terminal crosslinking telopeptide of Type I collagen peptides that are formed during collagen degradation, originating from the N-terminal telopeptide of collagen molecules Project: C48
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nuclear stain stain that highlights the nucleus (eg, Giemsa, safranin) Project: M54
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nuclear truncation an artifact that occurs when part of a nucleus is above and part of the nucleus is below the plane of sectioning. Nuclear truncation can result in the loss of FISH targets Project: MM07
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nuclease any of several enzymes, such as endonucleases and exonucleases, that hydrolyze nucleic acids Project: MM03, MM17, M55 NOTE 1: An endonuclease cleaves a nucleic acid (DNA or RNA) at specific internal sites in the nucleotide base sequence, while an exonuclease cleaves nucleotide bases sequentially from the free ends of a nucleic acid; NOTE 2: Five-prime nuclease assays are methods using a labeled probe that anneals to a polymerase chain reaction amplicon that is in turn cleaved by the 5′ to 3′ exonuclease activity of a thermostable DNA polymerase, releasing the fluorogenic tag from the 5′ end of the probe.
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nucleic acid a polynucleotide made up of dNTPs (DNA) and rNTPs (RNA) linked to one another by phosphodiester bonds, forming macromolecular structures Project: MM04
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nucleic acid amplification test molecular testing that uses any one of several nucleic acid target sequence amplification methodologies (eg, polymerase chain reaction, loop mediated amplification, transcription mediated amplification) as a component of the testing procedure to amplify the nucleic acid target of interest before testing or during the procedure before target detection Project: MM19
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nucleic acid amplification test qualitative or quantitative molecular assay for detection of the presence of pathogen nucleic acids (DNA or RNA) Alternate Term: nucleic acid test Project: POCT15
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nucleic acid extraction the separation of nucleic acids (RNA, DNA, total nucleic acid) from biological materials to perform amplification and analysis of nucleic acids Alternate Term: extraction Project: MM03, M55, MM19, MM22, MM24 NOTE: Initially, cell membranes, walls, and other protective structures must be lysed and cellular nucleases inactivated before separating desired nucleic acids from the cellular debris. Extraction procedures may combine purification or isolation of nucleic acids according to level of purity needed for downstream applications.
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nucleic acid probe single- or double-stranded oligonucleotide or polynucleotide of defined length complementary to specific sequences of nucleotides in nucleic acids (ISO 19001) Project: ISO 19001
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nucleic acid sequence–based amplification amplification of RNA nucleic acid target of interest, the end product of which is single stranded RNA Project: MM19
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nucleic acid test (quantitative) molecular assay for quantification of viral nucleic acids (DNA or RNA) Project: M53 NOTE: Sometimes referred to as “viral load assays.”
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nucleic acid test (qualitative) molecular assay for detection of the presence of viral nucleic acids (DNA or RNA) Project: M53 NOTE: Sometimes referred to as “nucleic acid amplification test.”
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nucleic acid-modifying enzymes enzymes that act directly on DNA or RNA to change the bases or degrade the polymer Project: MM10
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nucleotides chemical compounds that consist of a purine or pyrimidine base, a sugar, and one or more phosphate groups Project: H58 NOTE: The important nucleotides within platelets are the adenine nucleotides adenosine monophosphate, adenosine diphosphate, and adenosine triphosphate.
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nucleus a cellular inclusion composed of chromatin; morphology often used to help identify intestinal protozoa (Entamoeba and Dientamoeba spp.) Project: M28
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nuclide a species of atoms with specified numbers of protons and neutrons in its nucleus NOTE: The nature of a nuclide is indicated unambiguously by the chemical symbol of the element and the number of nucleons (sum of protons and neutrons = mass number) shown as an upper index to the left of the elemental symbol; for example: 12C, 32P
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null hypothesis 1) In simplest terms, the null hypothesis states that the results observed in a study, experiment, or test are no different from what might have occurred as a result of the operation of chance alone; 2) The hypothesis that the independent variable(s) under study has no association with or effect upon the dependent or outcome variable(s) Project: GP45
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null hypothesis in interference testing, a statement to be tested at a specified confidence level, that a substance does not cause interference greater than a specified limit (dnull)
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null hypothesis the hypothesis of no difference or no differential effects beyond random variation
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null measurement uncertainty measurement uncertainty where the specified measured quantity value is zero (JCGM 200:2012) Project: ISO IEC Guide 99 NOTE 1: Null measurement uncertainty is associated with a null or near zero indication and covers an interval where one does not know whether the measurand is too small to be detected or the indication of the measuring instrument is due only to noise (JCGM 200:2012); NOTE 2: The concept of ‘null measurement uncertainty’ also applies when a difference is obtained between measurement of a sample and a blank (JCGM 200:2012).
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number fraction the number of defined particles or elementary entities constituting the specified component divided by the total number of defined particles in the system (IUPAC/IFCC1978- 4.15)
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number of entities the kind of quantity representing the total of all discrete items counted as of the same kind NOTE: Formerly, and less inclusively, referred to as the number of particles (IUPAC/IFCC1978-4.5).
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numerical quantity value number in the expression of a quantity value, other than any number serving as the reference (JCGM 200:2012) Alternate Term: numerical value of a quantity; numerical value Project: ISO IEC Guide 99 NOTE 1: For quantities of dimension one, the referenceis a measurement unit which is a number and thisis not considered as a part of the numerical quantity value (JCGM 200:2012); EXAMPLE: In an amount-of-substance fractionequal to 3 mmol/mol, the numerical quantity valueis 3 and the unit is mmol/mol. The unit mmol/mol isnumerically equal to 0.001, but this number 0.001 isnot part of the numerical quantity value, whichremains 3 (JCGM 200:2012); NOTE 2: For quantities that have a measurement unit(ie, those other than ordinal quantities), the numericalvalue {Q} of a quantity Q is frequently denoted{Q} = Q/[Q], where [Q] denotes the measurement unit (JCGM 200:2012); EXAMPLE: For a quantity value of 5.7 kg, thenumerical quantity value is {m} = (5.7 kg)/kg = 5.7.The same quantity value can be expressed as5700 g in which case the numerical quantity value{m} = (5700 g)/g = 5700 (JCGM 200:2012).
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numerical value (of a quantity) quotient of the value of a quantity and the unit used in its expression; EXAMPLES: in the examples in 1.18, the numbers:a) 5,34, 534;b) 0, 152 , 152;c) 0,012 , 12
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numerical value the number that gives the magnitude of the measured quantity when multiplied by the unit (IUPAC/IFCC1978-3.4)
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numerical value equation mathematical relation between numerical quantity values, based on a given quantity equation and specified measurement units (JCGM 200:2008) Alternate Term: numerical quantity value equation Project: ISO IEC Guide 99 EXAMPLE 1: For the quantities in Example 1 in item 1.22, {Q1} = ζ {Q2} {Q3} where {Q1}, {Q2}, and {Q3} denote the numerical values of Q1, Q2, and Q3, respectively, provided that they are expressed in either base units or coherent derived units or both (JCGM 200:2012); EXAMPLE 2: In the quantity equation for kinetic energyof a particle, T = (1/2) mv2, if m = 2 kg and v = 3 m/s, then {T} = (1/2) × 2 × 32 is a numerical value equation giving the numerical value 9 of T in joules (JCGM 200:2012).
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objective (microscope) lens in a microscope that is nearest to the object under examination and magnifies the specimen in relation to the power of the objective Project: HS02, POCT10
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objective a statement of future expectations with measurable parameters and an indication of when the expectations should be achieved Project: QMS03, QMS06, QMS12, QMS01 Source: Quality Glossary EXAMPLE: Reduce turnaround time of stat test results to the emergency department by 30% within six months; NOTE 1: “Objective” is not synonymous with “goal”; NOTE 2: Objectives are derived from goals and clarify what must be accomplished.
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objective evidence data supporting the existence or verity of something (ISO 9000) Project: ISO/DIS 14971 NOTE: Objective evidence may be obtained through observation, measurement, testing, or other means. (ISO 9000)
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objective evidence information that can be verified and proven true, based on facts, or obtained through observation, measurement, test, or other means (modified from ISO 9000, ISO 19011) Project: QMS15 NOTE: Previously referred to as “audit evidence.”
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objectives the general questions the trial was designed to answer Project: GP45 NOTE: Objectives may be associated with one or more hypotheses that, when tested, will help answer the question.
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obligate anaerobe a microorganism that will not grow on the surface of agar in the presence of oxygen Project: M56
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OBR an Health Level Seven abbreviation for observation request Project: AUTO01, AUTO07, AUTO02, AUTO03
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observation a point-of-care test result and all its associated information Project: POCT02
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observation a measurement of a single variable or a single value derived logically and/or algebraically from other measured or derived values Project: AUTO16 NOTE: A test result is an observation.
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observation item of objective evidence found during an audit, usually of lesser importance than a finding Project: QMS15 NOTE: An observation might or might not need a corrective action response.
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observation recipient a computer system that manages point-of-care test results and physician orders within a health care institution Project: POCT02 NOTE: Examples include laboratory information systems, clinical information systems, and other systems that serve as the final repository of point-of-care results.
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observation recipient the observation recipient provides services to manage point-of-care test results and ordering information within a health care institution Project: POCT01 NOTE: In current point-of-care information management solutions, this function is often performed by laboratory information systems, clinical information systems, and other systems that serve as the final repository of point-of-care results.
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observation reporting interface the interface communication and message formats and protocols for transferring data between an observation reviewer (a data manager) and observation recipient computers Alternate Term: ORI Project: POCT02 NOTE: The messages contain information, including the observation or patient results and associated physician orders.
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observation reporting interface the observation reporting interface specifies messages sent between observation reviewers and observation recipients Project: POCT01 NOTE: The messages contain information regarding observation results and associated orders.
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observation request a segment used to transmit information specific to an order for a diagnostic study or observation, physical exam, or assessment, and define the attributes of a particular request for diagnostic services (eg, laboratory, electrocardiogram) or clinical observation (eg, vital signs or physical exam) (HL7 V2.6) Alternate Term: observation request segment Project: AUTO01, AUTO02, AUTO03
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observation reviewer the observation reviewer provides services to support the management of test results, quality assurance and quality control data, and medical orders Project: POCT01 NOTE: In current point-of-care information management solutions, this function is often performed by a data manager.
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observation reviewer a computer that supports the management of test results, quality control data, quality assurance, and medical orders Project: POCT02 NOTE: The observation reviewer is also called a data manager and is the computer that resides between the point-of-care testing device and the final observation recipient computer (the laboratory information system, the hospital information system, or other database for permanent storage and retrieval of point-of-care results).
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observation segment a segment used to transmit a single observation or observation fragment, and representing the smallest indivisible unit of a report Alternate Term: result segment Project: AUTO01, AUTO02, AUTO03 NOTE: Its principal mission is to carry information about observations in report messages (HL7 V2.6).
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observed response the measured physical or chemical parameter used to identify or quantify an analyte in comparison to an appropriate calibration system Project: EP14 NOTE: The observed response may be used by a system’s internal processor and, therefore, the value is often not available to the testing personnel; examples include absorbance units, radioactive counts, and millivolt readings.
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observed value the value of a characteristic obtained as the result of a single observation (ISO 3534-1/93-3.6)
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observed value for a patient laboratory test result, the value of a particular type of quantity, obtained by observation or measurement of a test subject (ie, patient or patient's specimen) Project: EP28
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observer individual who watches selected segments of an exercise as it unfolds, while remaining separated from player activities Project: GP36
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OBX an Health Level Seven abbreviation for observation/result segment Project: AUTO01, AUTO02, AUTO03
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occupational exposure reasonably anticipated skin, eye, mucous membrane, or parenteral contact with blood or other potentially infectious materials that may result from the performance of an employee’s duties (29 CFR 1910.1030) Project: X3-R, M29 NOTE: “Reasonably anticipated” includes the potential for accidental exposure.
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occurrence something that happens that does not conform to the service’s established policies, processes, or procedures; other terms frequently used include accident, adverse event, error, event, incident, nonconformance, and nonconformity Project: POCT07
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occurrence something that happens; an event, incident
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ocular (eyepiece) lens used in a microscope for magnification of the primary image Project: HS02, POCT10 NOTE: The lens nearest to the eye.
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OD260/OD280 the ratio of the absorbance of a nucleic acid solution at a wavelength of 260 nm divided by the absorbance of the same solution at a wavelength of 280 nm NOTE: It is a spectrophotometric method of assessing nucleic acid purity. For pure DNA solutions, the ratio would be ≥ 1.8 and for pure RNA solutions, the ratio would be ≥ 2.0.
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odds the ratio of the probability of occurrence of an event to that of nonoccurrence, or the ratio of the probability that something is so, to the probability that it is not so Project: GP45
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odds of being affected given a positive result ratio of the number of affected to unaffected individuals among those with positive test results, ie, ratio of true-positives to false-positives Project: I/LA25
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odds ratio the ratio of two odds Project: GP45 NOTE 1: In a case-control study, the exposure odds ratio is the ratio of the odds of an exposure in the cases to the odds of an exposure in the controls; NOTE 2: With incident cases, unbiased subject selection, and a “rare” disease (eg, under 2% cumulative incidence rate over the study period) the exposure odds ratio is an approximate estimate of the risk ratio.
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off scale indicates that minimal inhibitory concentration measured for the organism is not within the range of concentrations tested Project: M23
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official record official copy or original record having the legally recognized and enforceable quality of establishing a fact Project: QMS26 NOTE: Official records are kept for their full retention period.
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off-label describes use of a device beyond its cleared, approved, or intended use Project: POCT17
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off-label use as it pertains to automated systems for immunohematological testing, this is the use of an automated system for purposes other than described by the intended-use statement in the Instructions for use and/or user’s manual Project: I/LA33 NOTE: As it pertains to reagents used with an automated system, it is the use of reagents not specifically intended for use on an automated system or reagents intended for use on an automated system but used in a manner different than that prescribed by the reagent’s Instructions for Use and/or the user’s manual.
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off-line in water monitoring systems, referring to measurement devices that are not directly coupled to the water stream Project: GP40
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offset in the slope-intercept portrayal of a line, the line can be expressed by the formula y = mx + b, in which m is the slope and b is the y offset (the value of y when x = 0) Project: POCT05
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off-system measurement unit measurement unit that does not belong to a given system of units (JCGM 200:2012) Alternate Term: off-system unit Project: ISO IEC Guide 99 EXAMPLE 1: The electronvolt (about 1.602 18 × 10-19 J) is an off-system measurement unit of energy with respect to the SI (JCGM 200:2012); EXAMPLE 2: Day, hour, and minute are off-system measurement units of time with respect to the SI (JCGM 200:2012).
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off-system unit (of measurement) unit of measurement that does not belong to a given system of units (eg, day, hour minute are off-system units with respect to the SI (VIM93-1.15))
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off-the-clot serum the liquid remaining after neat whole blood has coagulated and the clot has retracted and/or been spun down in a centrifuge to separate the clot from the liquid portion Project: AST03, C37
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oligo(dT) oligodeoxynucleotide polymer of deoxythymidine, typically 20 to 80 DNA bases in length and covalently bound to matrix cellulose Project: MM13 NOTE: Used during messenger RNA isolation procedures.
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oligonucleotide a short molecule, usually six to 100 nucleotides in length, of single-stranded DNA, which is usually synthesized chemically Project: MM03, M55, MM22, MM24
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oligonucleotide a small polynucleotide generally synthesized on a machine Project: MM09, M55 NOTE: Oligonucleotides are used as amplification primers or as probes.
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oligonucleotide a relatively short polymer of nucleotides Project: MM10, M55
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oligonucleotide ligation assay a solution-based, sequence-specific enzymatic reaction technology based on the joining of two adjacent oligonucleotide probes using a DNA ligase while they are annealed to a complementary DNA target (eg, polymerase chain reaction product); an enzymatic DNA ligation reaction that determines the genotype of a target Project: MM22, MM24
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omalizumab for asthma and allergy patients who receive subcutaneous injections of omalizumab, which is a humanized immunoglobulin G1-kappa antihuman immunoglobulin E fragment crystallizable therapy, their immunoglobulin E will exist in two states: free immunoglobulin E (unbound with omalizumab) and complexed omalizumab-bound immunoglobulin E, which is blocked by the antihuman immunoglobulin E from binding to the alpha chain of the high affinity Fc-epsilon receptor 1 Project: I/LA20 NOTE: Caution should be exercised when analyzing blood from allergy patients receiving omalizumab, since the therapeutically administered antihuman immunoglobulin E can alter the accuracy of some total and allergen-specific immunoglobulin E assays.
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on scale indicates that minimal inhibitory concentrations to be tested include at least one dilution above and one dilution below the minimal inhibitory concentration end point Project: M07, M23
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oncogene a gene that encodes a protein that can transform cells in culture or induce cancer in animals Project: MM23
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one-sided test statistical test of significance that is used when the alternative hypothesis states the direction (positive or negative) of the interference effect Project: EP07 EXAMPLE: +0.2 mg/dL difference at a creatinine concentration of 1.0 mg/dL.
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one-tailed test the test of a given statistical hypothesis in which only a value of the statistic that is, for example, sufficiently large will lead to rejection of the hypothesis tested Project: ILA29
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on-line in water monitoring systems, referring to measurement devices directly coupled to the water stream Project: GP40
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on-scale MIC test result result from a MIC test when there is growth in at least one but not all concentrations tested (ISO 20776-2) Project: ISO 20776-2
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on-test product an in vitro diagnostic product (eg, reagent, calibrator, control, diluent) placed under defined conditions for defined durations to evaluate stability Project: EP25
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oocyst the encysted form of the fertilized macrogamete, or zygote, in coccidian parasites; may contain one or two immature sporonts, with the eventual development of sporocysts (Isospora belli) Project: M28
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oomycete fungus-like eukaryotic microorganism originally grouped with fungi
Project: M54
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open reading frame (orf) in general, a sequence of DNA in an organism’s genome that has a no stop codon and thus may encode part or all of a protein. Some open reading frames for known genes are defined as having a specific start (initiation codon) and stop (termination codon) site, but not all open reading frames encode known proteins or polypeptides Project: M55
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open reading frame of unknown function (orfX) an open reading frame of unknown function present in the chromosome of Staphylococcus aureus isolates Project: M55
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open system requires either addition of reagents or transfer of the amplicon to another reaction vessel Project: MM19
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open system a system in which manufacturer software applications are installed and running on computers supplied and managed by the health care delivery organization Project: AUTO11 EXAMPLE: An in vitro diagnostic software system installed on health care delivery organization–provided computers.
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Open System Interconnection Model a layered abstract description for communications and computer network protocol design, developed as part of the Open Systems Interconnect initiative Project: AUTO09
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open-container sampling the action of aspirating a sample from a specimen container from which the closure has previously been removed Project: AUTO01, AUTO02 NOTE: The sample probe contacts the surface of the specimen without other physical barriers.
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open-tube sampling See open-container sampling Project: AUTO02
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operating system software that controls the execution of programs, and that provides services such as resource allocation, scheduling, input/output control, and data management Project: AUTO08 NOTE: Usually, operating systems are predominantly software, but partial or complete hardware implementations are possible (ISO/IEC International Standard 812).
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operational qualification confirmation that the automated system is capable of operating within established limits and tolerances Project: I/LA33
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operational qualification process to confirm that the equipment or process conforms to the manufacturer’s specifications for its intended use Project: QMS18, MM17, QMS01 Source: Quality Glossary NOTE: Operational qualification can be performed by the manufacturer’s technical service engineer.
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operational qualification a series of tests that ensure equipment and its subsystems will operate within their specified limits consistently and dependably Project: H62 NOTE: Operational qualification can be performed by the manufacturer’s technical service engineer.
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operator a person who collects the specimen and/or performs the test Project: AST03
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operator a person who is authorized to perform blood glucose testing Project: POCT13
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operator person handling equipment Project: POCT09
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operator the person or persons in control of the sample or prepared subsample during performance of the test Project: H20, POCT07 NOTE: Operators are required for the reference method, routine method, and automated method.
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operator a person who is authorized to perform point-of-care blood glucose testing Project: POCT12
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operator the person or persons in control of the specimen during collection and performance of the test Project: POCT08, POCT15 NOTE: An alternative term is “testing personnel.”
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opportunistic infection an infection caused by pathogens (bacterial, viral, fungal, or protozoan) that rarely cause disease in a healthy host. Opportunistic infections often signal an immune-compromised host Project: NBS06
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opportunity for improvement condition that, when improved, should result in significant enhancement of organizational efficiency and effectiveness and/or customer satisfaction Project: QMS06, QMS01, QMS17 Source: Quality Glossary
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optimal cutting temperature compound a widely used embedding medium for tissues for histopathological analysis Project: MM13
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ORC an abbreviation for an Health Level Seven common order segment (HL7 V2.6) Project: AUTO01, AUTO02, AUTO03
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order a battery or test ordered by a ward and/or a physician to a laboratory, to be performed on one or more specimens collected from a patient Project: AUTO16
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order filler the actor, often played by the laboratory information system, which manages orders on the laboratory side Project: AUTO16
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order group a set of orders placed together by a ward and/or a physician to one or more laboratories for a patient, to be performed on one or more specimens collected from this patient Project: AUTO16 NOTE: Also called the “laboratory request.”
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order of draw standardized sequence used during the blood collection process for the filling of the blood collection tubes to minimize carryover of tube additives from tube to tube Project: GP34
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order placer the actor, often played by the hospital information system or the clinical information system, to generate, place, and manage orders Project: AUTO16
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order set a grouping of orders that are usually all necessary to characterize a particular disease or disorder (eg, acute myocardial infarction) or a common patient process (eg, admission or presurgical) Project: GP49
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ordinal results of tests that fall in an approximate range of values (eg, trace, moderate) Project: H62 NOTE 1: Data are ordered rather than continuous; NOTE 2: See semiquantitative.
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ordinal quantity quantity, defined by a conventional measurement procedure, for which a total ordering relation can be established, according to magnitude, with other quantities of the same kind, but for which no algebraic operations among those quantities exist (JCGM 200:2012) Project: ISO IEC Guide 99, C51 EXAMPLE 1: Rockwell C hardness (JCGM 200:2012); EXAMPLE 2: Octane number for petroleum fuel (JCGM 200:2012); EXAMPLE 3: Earthquake strength on the Richter scale (JCGM 200:2012); EXAMPLE 4: Subjective level of abdominal pain on a scale from zero to five (JCGM 200:2012); NOTE 1: Ordinal quantities can enter into empirical relations only and have neither measurement units nor quantity dimensions. Differences and ratios of ordinal quantities have no physical meaning (JCGM 200:2012); NOTE 2: Ordinal quantities are arranged according to ordinal quantity-value scales (see 1.28) (JCGM 200:2012); EXAMPLE 5: +, ++, +++ for arbitrary mass concentration of protein in urine; EXAMPLE 6: Urine protein amount-of-substance concentration expressed as 0, 1, 2, or 3 with reference to a measurement procedure.
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ordinal quantity-value scale quantity-value scale for ordinal quantities (JCGM 200:2012) Alternate Term: ordinal value scale Project: ISO IEC Guide 99 EXAMPLE 1: Rockwell C hardness scale (JCGM 200:2012); EXAMPLE 2: Scale of octane numbers for petroleum fuel (JCGM 200:2012); NOTE: An ordinal quantity-value scale may be established by measurements according to a measurement procedure (JCGM 200:2012).
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ordinal scale scale with an ordered set of possible values for a given kind-of property that are each a word or symbol used for ranking according to magnitude, but where differences or ratios between values have no arithmetic meaning
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ordinary least squares linear regression least squares linear regression that usually refers to nonweighted least squares regression Project: EP09, EP14 NOTE: Ordinary linear regression can also be described as uniformly weighted ordinary least squares regression.
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organic solvents defined by the US Environmental Protection Agency as a volatile organic liquid that is used for dissolving or dispersing constituents in a coating or contact adhesive, adjusting the viscosity of a coating or contact adhesive, or cleaning equipment Project: QMS04
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organization person or group of people that has its own functions with responsibilities, authorities, and relationships to achieve its objectives (ISO 9000) Project: QMS01 Source: Quality Glossary
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original squamocolumnar junction the junction between the squamous and columnar epithelium at birth Project: GP15
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osteocalcin noncollagenous protein in bone produced by osteoblasts Alternate Term: bone GLA-protein, bone gamma-carboxyglutamic acid protein Project: C48 NOTE: It consists of 49 amino acids.
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other potentially infectious materials (OPIMs) human body fluids including semen; vaginal secretions; urine; cerebrospinal fluid; synovial fluid; pleural fluid; pericardial fluid; peritoneal fluid; amniotic fluid; saliva; body fluids which may be contaminated with blood; unfixed tissue; HIV or hepatitis virus containing cell or organ cultures; blood and tissue from infected animals; reagents; infectious waste; and cultures (ie, nonpatient specimens)
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other potentially infectious materials 1) the following human body fluids: semen, vaginal secretions, cerebrospinal fluid, synovial fluid, pleural fluid, pericardial fluid, peritoneal fluid, amniotic fluid, saliva in dental procedures, any body fluid that is visibly contaminated with blood, and all body fluids in situations where it is difficult or impossible to differentiate between body fluids; 2) any unfixed tissue or organ (other than intact skin) from a human (living or dead); and 3) HIV-containing cell or tissue cultures, organ cultures, and HIV- or hepatitis B virus–containing culture medium or other solutions; and blood, organs, or other tissues from experimental animals infected with HIV or hepatitis B virus (29 CFR 1910.1030) Alternate Term: potentially infectious materials Project: M29
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out of range when an instrument or measuring device (used interchangeably) is used, control results outside of preset limits (out-of-range) indicate some degree of change in the performance of the overall measurement system, such as within the instrument system (electronic, mechanical, or flow), reagent system, or the control samples
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out of range when an instrument or measuring device (used interchangeably) is used, control results outside of preset limits (out-of-range) indicate some degree of change in the performance of the overall measurement system, such as within the instrument system (electronic, mechanical, or flow), reagent system, or the quality control materials Project: POCT13
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outbreak in bacterial strain typing, the increased incidence of an infectious disease in a specific place and time that is above the baseline rate for that place and time Project: MM24
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outbreak strain in bacterial strain typing, a set of isolates of the same species that are both epidemiologically related and genotypically related (ie, represent a single strain) Project: MM24
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outcome observed or measurable result of a process, project, or improvement initiative Project: QMS14, QMS03
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outcome change in health status and quality of life resulting from a specified intervention Project: ISO TR 15196
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outcome the sum of substance concentrations of the oxygen bound to hemoglobin as O2Hb and the amount dissolved in the blood (intra- and extracellular) Project: C25 NOTE: Formally termed the “concentration of total oxygen” (ctO2), the more commonly used term to represent this entity, “oxygen content,” is simpler, unambiguous and is preferred.
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outcome the results of the use of an intervention, a process, or medical care, the consequences of using a medical care process, or the consequences to the health and welfare of individuals or populations in a society Project: GP45 NOTE: Commonly used measures include: morbidity, mortality, quality of life measures, satisfaction with care, cost of care, length of stay, work days lost, complication rate, and readmission rate.
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outcome observed or measureable result of a project or improvement initiative Project: QMS16
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outcome the results from the intervention of health care Project: GP49 NOTE: There are a variety of outcomes: medical outcomes (eg, did a patient get better or worse from an intervention?), improvement rate (eg, did the intervention improve the patient’s health at a greater rate than the standard of care?), and overall cost (eg, was the most cost-effective approach used for patient care?).
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outer container material used in the packaging of the immediate container or containers of an IVD medical device, which can consist of a single component, a kit, or an assembly of different or identical components (ISO 18113-1)
Alternate Term: sales packaging Project: ISO 18113-1, ISO 18113-2, ISO 18113-3 NOTE: Adapted from EN 375:2001, definition 3.13 (ISO 18113-1).
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outlier the observation in a sample, so far separated in value from the remainder as to suggest that it may be from a different population, or the result of an error in measurement Project: ISO 3534-1/93-2.64, EP10, EP18, EP09 NOTE 1: It is also defined as a number of a set of values that is inconsistent with the other numbers of the set; NOTE 2: Statistical tests can be used to identify outliers, but visual inspection of data can serve as a sensitive indicator of when such tests are useful.
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out-of-control condition a process or component of a process that is not operating in its stable state Project: C24 NOTE 1: For quantitative measurement procedures, an out-of-control condition is usually described in terms of a shift or drift away from the stable mean of the measurement procedure, or as an increase in random imprecision above the stable imprecision of the measurement procedure; NOTE 2: May be referred to as an out-of-control error condition, or error condition.
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out-of-range result test result that is outside the expected range of testing results Project: NBS07, NBS06, NBS05, NBS01, NBS13, NBS09, NBS03, NBS02, NBS10 Source: Newborn Screening Glossary NOTE: See expected range.
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outpatient a patient who comes to the hospital, clinic, or dispensary for diagnosis and/or treatment but does not occupy a bed (Dorland's Illustrated Medical Dictionary. 33rd ed. Elsevier, Inc.; 2019) Project: PRE02
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output quantity See output quantity in a measurement model Alternate Term: output quantity in a measurement model Project: C51
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output quantity in a measurement model quantity, the measured value of which is calculated using the values of input quantities in a measurement model (JCGM 200:2008) Alternate Term: output quantity Project: ISO IEC Guide 99, C51
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output variable the dependent variable, the value of which is compared to the input (independent) variable NOTE: The output variable is represented by Y, with individual values of Y noted by yi (i represents an individual observation), and its value is plotted along the Y axis (ordinate); the mean of all the output variables ( yi) in the data pool is y.
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outside laboratory see referring laboratory Project: AUTO14
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overall percent agreement the proportion of subjects in whom the new test and the comparative method give the same outcome Project: MM17
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overgrowth studies investigations to determine increases in microorganism concentrations during simulated transport Project: M40
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overpack the outermost packaging used to enclose more than one complete package, each of which contains dangerous goods Project: M29
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overt incident event intrinsically recognizable as life threatening at inception Project: GP36 EXAMPLES: Hurricanes, tornados, floods, earthquakes, ice or wind storms, explosions; NOTE 1: An overt incident manifests as a sudden catastrophic event at a localized site or “hot zone.” Property damage may occur, and the victims are immediately and obviously injured; NOTE 2: Laboratory staff is principally responsible for supporting the clinical medical response to trauma, chemical exposure, or other potential insults affecting a surge of presenting victims.
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oxygen (O//O2) in chemistry, a colorless, odorless, gaseous (at STP) element of atomic mass 15.9994, atomic number 8, that is essential to most animal life Alternate Term: O; O2
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oxygen capacity (of hemoglobin in blood) the maximum amount of oxygen that can be carried by the hemoglobin in a given quantity of blood Alternate Term: hemoglobin-oxygen binding capacity (BO2) Project: C46
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oxygen content the sum of substance concentrations of the oxygen bound to hemoglobin as O2Hb and the amount dissolved in blood (intra- and extracellular, ie, partial pressure of oxygen) Project: POCT11, GP43, C46
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oxygen half-saturation tension (P50) the partial pressure of oxygen in a hemoglobin solution with an oxygen saturation of 50% (0.50) (IFCCEPpH92). See also Partial pressure
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oxygen saturation the amount of oxyhemoglobin in blood expressed as a percent fraction of the amount of hemoglobin able to bind oxygen (oxyhemoglobin plus deoxyhemoglobin); that is, SO2 = [O2Hb/O2Hb + HHb] · 100 Project: POCT11, NRSCL8 NOTE 1: Formally termed “oxygen saturation of hemoglobin available for oxygen binding” (IFCCEPpH92), the simpler term “oxygen saturation” is preferred, and, in the appropriate context, “saturation” alone is sufficient; NOTE 2: Alternative expressions that have been used are “functional” oxygen saturation, or oxygen saturation of “available” or “active” hemoglobin. Because these terms are either awkward or ambiguous, they are deprecated.
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oxygen saturation of active hemoglobin See oxygen saturation
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oxygen saturation of available hemoglobin See oxygen saturation.
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oxygen tension oxygen partial pressure or partial pressure of oxygen; See Partial pressure
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oxyhemoglobin the hemoglobin derivative obtained when hemoglobin (Fe++) binds reversibly with oxygen Project: C46
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oxyhemoglobin fraction (of total hemoglobin//fractional oxyhemoglobin) 1) the amount of oxyhemoglobin expressed as a fraction of the amount of total hemoglobin present; 2) the oxyhemoglobin substance fraction of the total hemoglobin Project: C46
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P50 (actual) the partial pressure of oxygen in blood with an oxygen saturation of 50% at actual values of pH, partial pressure of carbon dioxide, and temperature Project: C46
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P50 the partial pressure of oxygen in a hemoglobin solution with an oxygen saturation of 50% (0.50) (IFCCEPpH92)
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P50 the symbol used to represent the partial pressure of oxygen in a hemoglobin solution (usually blood) with an oxygen saturation of 50% Alternate Term: half-saturation oxygen tension Project: C46
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P50 (standard) the partial pressure of oxygen in blood with an oxygen saturation of 50% with the “standard” conditions of pH = 7.40, partial pressure of carbon dioxide = 40 mmHg (5.3 kPa), and temperature = 37°C Project: C46
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package insert instructions for use and other information supplied with the material that is not attached to any part of the package (modified from ISO 15197) Project: GP39, POCT18, GP34 NOTE: Labeling requirements are different for in vitro diagnostic devices receiving an emergency use authorization vs 510(k) products. As such, emergency use authorization products have instructions for use, as opposed to a package insert, which accompanies 510(k) products.
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package insert instructions for use and other information for the reagent system or control material that is supplied within the package, but not attached to any part of the package (ISO 15197) Project: ISO 15197
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package insert instructions for use and other information supplied with the reagents and the quality control material that is not attached to any part of the package (modified from ISO 17593) Project: ISO CD 17593, ISO DIS 17593
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packaging a receptacle and any other components or materials necessary for the receptacle to perform its containment function in conformance with the minimum packing requirements of 49 CFR 171.8 Project: M29
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packed cell volume volume fraction of the erythrocytes in blood (ISO 15197) Alternate Term: PCV; microhematocrit Project: ISO 15197, H20, H26 NOTE 1: Expressed either as a decimal fraction (SI) or as a percentage (conventional). SI units (L/L) are implied (ISO 15197). See the most current edition of CLSI document H07; NOTE 2: Sometimes referred to as “hematocrit” after the instrument originally used to estimate packed cell volume (ISO 15197).
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packed cell volume the measure of the ratio of the volume occupied by the red blood cells to the volume of whole blood, expressed as a fraction or percentage Alternate Term: hematocrit NOTE: The term hematocrit has been and often is used for this quantity.
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packed cell volume the measure of the ratio of the volume occupied by the red blood cells packed by centrifugation under specified conditions to the volume of whole blood, expressed as a fraction Alternate Term: hematocrit Project: H07
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packing instructions International Air Transport Association–defined directions shippers must follow to select, assemble, mark, label, and document the packing process for shipping dangerous goods Project: M29
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padded zeros additional zeros added most commonly at the beginning of, sometimes at the end of, or rarely within, a patient or specimen identification element (eg, accession number, medical record number, encounter number), in which the additional zeros are used to expand the identification element’s number of characters to a predetermined exact number of characters at all times Project: AUTO14
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paired absolute relative difference (PARD) a continuous glucose monitoring (CGM) performance metric mathematically similar to mean absolute relative difference. Instead of comparing the CGM system with a glucose reference measurement, PARD compares matched measurements from two CGM systems worn simultaneously by the same patient (see equation in POCT05)
Project: POCT05 NOTE: PARD is a metric for the precision of a CGM system.
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paired test system lupus anticoagulant tests of like principle that are paired as screening and confirmatory assays, eg, dilute Russell’s viper venom time screening test and dilute Russell’s viper venom time confirmatory test. Results from paired test systems may be expressed as a ratio between the two tests Project: H60
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pair-end read sequencing a method based on sequencing opposite ends of a DNA fragment of known size, allowing for a highly precise alignment of the reads
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pancreatic exocrine insufficiency impaired pancreatic exocrine function leading to insufficient digestive enzyme production for adequate digestion of lipids and proteins Project: NBS05 NOTE: Confirmatory diagnostic techniques include low or absent fecal elastase or reduction of the coefficient of fat absorption as measured from a 72-hour fecal sample accompanied by an accurate dietary record.
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pancreatic insufficiency impaired pancreatic exocrine function leading to insufficient digestive enzyme production for adequate digestion of lipids and proteins NOTE: Confirmatory diagnostic techniques include low or absent fecal elastase or reduction of the coefficient of fat absorption as measured from a 72-hour fecal sample accompanied by an accurate dietary record.
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pancreatic sufficiency pancreatic exocrine function leading to digestive enzyme production that is adequate for digestion of lipids and proteins Project: NBS05
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pancreatitis-associated protein a secretory protein of the pancreas, of which the production increases under physiological stress (including birth or cystic fibrosis) Project: NBS05
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panel the battery of identification substrates or antimicrobial dilutions tested on a microbial identification system or antimicrobial susceptibility testing system, respectively Project: M52
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panel reactive antibody refers to the percent of panel cells that react with patient serum Alternate Term: PRA Project: ILA29 NOTE: The PRA gives an indication of the probability of a positive crossmatch with the donor pool.
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panmictic ability of individuals in a population to interbreed without restrictions Project: MM24
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Pap test a sample of cells collected from the cervix (or vaginal cuff in posthysterectomy patients), prepared by conventional or liquid-based methods, and stained using the Papanicolaou staining technique for the purpose of screening for cervical cancer and precancerous lesions of the cervix and vagina Project: GP15
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Papanicolaou stain technique a method of polychromatic staining developed by George N. Papanicolaou to identify differences in cellular morphology, maturity, and metabolic activity Project: GP15
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parallax the apparent displacement of an observed object due to a change in the position of the observer, or by the observer’s use of both eyes versus one eye or the other for the observation
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parallelism extent to which the dose-response relationship between two materials (ie, calibrator vs unknown specimens) is constant for the examined range of concentrations Project: I/LA34, I/LA20 NOTE 1: For example, calibrator versus unknown specimens; NOTE 2: Parallelism is a property (and a requirement) of quantitative immunoassays in which the calibrator and test sera produce parallel dose-response curves. As a consequence, the same estimate of analyte concentration in the test specimen is generated by the assay once it is corrected for dilution, irrespective of the actual dilution of the specimen analyzed. Good parallelism can be demonstrated by analysis of multiple dilutions of serum in the same assay run. Low interdilutional “dose” coefficients of variation provide evidence that the calibrator and test portions of the immunoassay are parallel. See “linearity.”
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parallelism demonstration of surrogate matrix and native matrix equivalence through dilution Project: C64
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parallelism extent to which the dose-response relationship between two materials (ie, calibrator vs unknown specimens) is constant for the examined range of concentrations or activities Project: H48
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parameter a quantity used in describing the probability distribution of a random variable (ISO 3534-1/93-1.12) Project: ISO 3534-1/93-1.12, H20 NOTE: The term parameter should not be used as a synonym for analyte or measurand.
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parametric statistical tests that are applied to datasets that exhibit normal distribution Project: MM06
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parametric (statistical procedure) one that involves an assumption as to the kind of distribution underlying the data and focuses on estimating a small number of characterizing quantities, called the parameters of the distribution Project: EP24, EP17 NOTE: For example, a normal (gaussian) distribution is specified by just two parameters, that is, its mean and its standard deviation.
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parasite an organism living on or in, and at the expense of, another organism Project: M28
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paratope the functional elements of an antibody involved in recognition and binding of the epitope of the antigen Project: I/LA28 NOTE: Although these binding amino acids can be defined precisely by X-ray crystallography, in practice, the paratope is the variable region of the antibody that encodes the specificity of binding.
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parenteral piercing mucous membranes or the skin through such events as needlesticks, human bites, cuts, and abrasions Project: M29
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parenteral nutrition intravenous administration of nutrients
Project: NBS09, NBS03
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Pareto analysis a sorted table or graph that lists events in a decreasing order of importance Alternate Term: Pareto chart Project: EP18 NOTE: Pareto analysis uses the idea that a large majority of problems (80%) are produced by a few key causes (20%).
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parsimony the trait of being the least complicated explanation for an observation where the last common ancestor of two DNA sequences may be inferred by choosing the sequence that would require the smallest number of mutations to produce the two sequences observed Project: MM10
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partial pressure (of a component in a solution) the pressure that would exist in a hypothetical ideal gas phase, in equilibrium with the solution (IUPAC/IFCC-1984) Project: C12, C21, C25, C27, C32, C33, C41, GP43 NOTE 1: Commonly expressed in mmHg, the height, in millimeters, of a column of pure mercury at a specified temperature that exerts the same force (pressure) as the gas; NOTE 2: This may also be expressed in the force unit, Paschal (Pa); NOTE 3: When referring to specific gases or mixtures, the entity whose tension is being expressed follows the P symbol, either on the same line in the same font size, or on the same line in smaller font size and/or subscripted; NOTE 4: When referring to a specific source of the gas, the source symbol is found either parenthetically after the quantity-entity symbol (IFCC/IUPAC recommendation), or as a subscript to the tension symbol. Thus, for the oxygen tension of arterial blood, P O2(aB) or PaO2.
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partial pressure (of a gas in a solution) pressure that would exist in a gas phase, in equilibrium with the solution Alternate Term: tension Project: POCT11, C46
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partial thromboplastin a phospholipid preparation that facilitates the in vitro interaction of coagulation factors NOTE: This is another crude reagent used in the activated partial thromboplastin time. It is a phospholipid mixture derived from thromboplastin reagent by removal or deactivation of the protein. See also Activated partial thromboplastin time.
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particulates discrete quantities of solid matter dispersed in water Alternate Term: fines Project: GP40
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Passing-Bablok regression nonparametric procedures to estimate slope and intercept parameters from a measurement procedure comparison experiment Project: EP09
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passive safety device a device that incorporates a safety mechanism that does not rely on the worker to activate it and is in effect throughout the use of the device Project: X3-R
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path of workflow sequential processes that transform an order into the information contained in the report of results, including preexamination, examination, and postexamination procedures Project: QMS06, QMS07, QMS25, GP23, QMS16, QMS21, QMS03, QMS01 Source: Quality Glossary
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pathogen a microorganism (bacterium, mycobacterium, fungus, parasite, virus, plasmid, genetic element, proteinaceous infectious particle, or genetically modified organism) that is known to cause or is reasonably expected to be able to cause disease in humans or animals Project: M29, MM17
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pathogenic capable of producing disease and can be used to describe both pathogenic bacteria and a pathogenic mutation Project: MM22, MM24
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pathogenic variant a DNA sequence that is associated with a deleterious outcome Project: NBS05, NBS10
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pathogenic variant with varying clinical consequences a DNA variant with incomplete penetrance Project: NBS05 NOTE: In the case of cystic fibrosis, this refers to cystic fibrosis transmembrane conductance regulator (CFTR) gene variants that (when paired with another cystic fibrosis–causing CFTR variant on the opposite chromosome) sometimes cause cystic fibrosis, sometimes cause single organ system CFTR-related disorder, and sometimes have no clinical phenotype.
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pathogens 1) Risk Group 1 (low individual and community risk): This group includes those microorganisms, bacteria, fungi, viruses, and parasites that are unlikely to cause disease in healthy workers or animals; 2) Risk Group 2 (moderate individual risk, limited community risk): This group includes pathogens that can cause human or animal disease but under normal circumstances are unlikely to be a serious hazard to healthy laboratory workers, the community, livestock, or the environment; 3) Risk Group 3 (high individual risk, low community risk): This group includes pathogens that usually cause serious human or animal disease; can result in serious economic consequences, but do not ordinarily spread by casual contact from one individual to another; or that can be treated by antimicrobial or antiparasitic agents; 4) Risk Group 4 (high individual risk, high community risk): This group includes pathogens that usually produce very serious human or animal disease, which is often untreatable and may be readily transmitted from one individual to another (or from animal to human or vice versa), directly or indirectly, or by casual contact Project: ISO/DIS 15190 (March 2002), QMS04 NOTE 1: Laboratory exposures rarely cause infection leading to serious disease; effective treatment and preventive measures are available and the risk of spread is limited; NOTE 2: In Europe “Risk groups I, II, III, and IV” are termed “Hazard Groups 1, 2, 3, and 4.” For the purpose of this guideline, the terms may be considered interchangeable and local usage will determine the actual terminology required; NOTE 3: Medical laboratories dealing with Risk Group III and IV infectious agents will need additional requirements to ensure safety.
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pathophysiology the physiology of disordered function Project: GP48
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pathway asequence of reactions, usually controlled and catalyzed by enzymes, by which one organic substance is converted to another (RHUD1.7CD)
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patient laboratory test result See observed value
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patient location location of the patient at the time a specimen for culture is obtained Project: M39 NOTE: The location may be a specific hospital designation or a less specific designation, such as inpatient, outpatient, intensive care unit, or nursing home facility.
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patient outcomes the impact of medical care on a patient’s well-being in terms that are perceptible to the patient, including such things as functional status, health status, and quality of life Project: GP45
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patient safety a health care sector discipline that applies safety science methods toward the goal of achieving a trustworthy health care delivery system Project: GP47 NOTE: Patient safety is also an attribute of health care systems; it minimizes the incidence and effect of, and maximizes recovery from, adverse events.
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patient sample a specimen without modification or a specimen modified before measurement Project: EP39 NOTE: Examples of modifications are use of chemical additives, extraction, centrifugation, or other physical separation techniques and preexamination steps.
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patient sample one or more parts taken from a specimen (JCGM 200:2012) obtained in a patient-centric clinical care setting Project: EP12 EXAMPLE: A portion of serum taken from a specimen of coagulated blood.
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patient self-testing testing by a patient or caregiver on blood or body fluid obtained from the patient Project: POCT14
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patient specimen human or animal material collected directly from humans or animals and transported for research, diagnosis, investigational activities, or disease treatment or prevention. Patient specimens include excreta, secreta, blood and its components, tissue and tissue swabs, body parts, and specimens in transport media (eg, transwabs, culture media, and blood culture bottles) (49 CFR 173.134) Alternate Term: diagnostic specimen; clinical specimen Project: M29
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patient-specific identifier any numeric or alphanumeric code used to uniquely identify a patient within a health register or a health records system Project: PRE05, PRE01, GP33
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peak resolution the separation of two peaks (tR2>tR1) in terms of their average peak width at base (wb): Rs=2(tR2-tR1)/(wb1+wb2) Project: C43 NOTE: In the case of two adjacent peaks it may be assumed that wb1=wb2, and thus, the width of the second peak may be substituted for the average value: Rs=(tR1-tR2)/wb2.
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peer group participants in a proficiency testing survey that use the same type of platform, assay, technology, or category of test (eg, laboratory developed) whose data are analyzed and reported together Project: MM14
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peer group in proficiency testing, a group of presumably identical test systems Project: EP15
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pellet a solid and visible mass of molecules or particles (such as proteins, nucleic acids, or cells), which is typically obtained from a liquid medium in a conical tube by centrifugation Project: MM13
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penetrance the proportion of individuals with a variant causing a particular disorder who exhibit clinical symptoms of that disorder Project: MM19 NOTE: This most often refers to autosomal dominant conditions.
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pentamer See major histocompatibility complex pentamer Project: I/LA26
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peptide a sequence of two to 50 amino acids joined by amide bonds Project: C64
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percent spillover amount of fluorescence emitted by a fluorophore measured at a secondary (spillover) detector as a ratio to the amount of fluorescence emitted by the same fluorophore measured at its primary detector Project: H62 NOTE: See spillover matrix and fluorescence spillover.
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percent time above minimal inhibitory concentration the cumulative percentage of a 24-hour period that the drug concentration exceeds the minimal inhibitory concentration. It should be stated explicitly if the period is other than 24 hours Project: M23
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percutaneous parenteral inoculation of infectious material or transfusion of blood or blood products Project: M29, QMS04
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percutaneous coronary intervention any one of a number of intervention procedures in which a catheter is inserted into a coronary artery for the purpose of removing obstruction by an atherosclerotic plaque; these include percutaneous transluminal coronary angioplasty, atherectomy, and coronary stent placement Project: POCT14
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performance characteristic one of the parameters used to define the performance of an IVD medical device (ISO 18113-1)
Alternate Term: metrological property Project: ISO 18113-1, ISO 18113-2, ISO 18113-3 NOTE: Information about more than one performance characteristic is usually required to evaluate the suitability of an IVD medical device for its intended medical use (ISO 18113-1); EXAMPLES: Detection limit, precision, specificity (ISO 18113-1).
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performance characteristic a property of a test that is used to describe its quality (42 CFR 493) Project: POCT04, H26 NOTE 1: Examples include accuracy, precision, analytical sensitivity, analytical specificity, reportable range, and reference interval; NOTE 2: A performance characteristic is a measurable quantity that can be given an experimentally determined value, such as trueness (bias), repeatability standard deviation, or limit of detection.
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performance characteristics parameters that describe the important functional qualities of a particular method Project: MM09, MM17 NOTE: The performance characteristics of an analytical method used under a given set of experimental conditions are a set of quantitative and experimentally determined values for parameters of fundamental importance in assessing the suitability of the method for any given purpose.
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performance claim specification of a performance characteristic of an IVD medical device as documented in the information supplied by the manufacturer (ISO 18113-1)
Project: ISO 18113-1 NOTE 1: This can be based upon prospective performance studies, available performance data or studies published in the scientific literature (ISO 18113-1); NOTE 2: Adapted from EN 13612:2002, definition 2.7 (ISO 18113-1).
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performance claims the established analytical and clinical performance characteristics of a test method Project: EP19 NOTE: The performance characteristics are developed and validated during the Establishment Stage and should be verified during implementation of the test method.
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performance evaluation investigation of a device intended to become an in vitro diagnostic medical device for the purpose of establishing or verifying its performance claims (ISO 18113-1) Alternate Term: performance, investigational use only Project: ISO 18113-1, ISO 18113-2, ISO 18113-3, H57 NOTE: May be based upon prospective performance studies, available performance data or studies published in the scientific literature.
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performance evaluation formal determination of an individual’s job-related actions and their outcomes within a particular position or setting. It is a measure of the accomplishment, conformance, performance, and suitability of an individual Project: QMS16 NOTE 1: The performance evaluation is based on predetermined performance standards or criteria; NOTE 2: Also known as a performance assessment or performance appraisal.
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performance improvement continuous study and adaptation of a health care organization’s functions and processes to increase the probability of achieving desired outcomes and to better meet the needs of individuals and other users of services
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performance measurement system automated database(s) that facilitates performance improvement in health care organizations through the collection and dissemination of process and/or outcome measures of performance NOTE: Measurement systems must be able to generate internal comparisons of organization performance over time and external comparisons of performance among participating organizations at comparable times
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performance qualification confirmation that the automated system produces acceptable outcomes under normal operating conditions and functions according to laboratory, regulatory, and accrediting agency requirements Project: I/LA33 NOTE 1: Performance qualification examines automated system performance with routine sample testing as well as performance when nonroutine samples are tested; NOTE 2: Performance qualification represents the final qualification of the automated system.
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performance qualification process to confirm that the equipment or process will perform to the organization’s own specified needs and intended use, producing acceptable results under normal operating conditions Project: H62 NOTE 1: Performance qualification testing confirms that the equipment performs as expected when used at the expected capacity and under usual conditions, eg, while running calibration beads, or a validated assay; NOTE 2: Performance qualification needs to be performed by laboratory personnel before use in testing and examinations. Performance qualification testing confirms that the equipment performs as expected when used at the expected capacity and under usual conditions, eg, while running CS and T beads or a validated assay.
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performance qualification process to confirm that the equipment or process will perform to the organization’s own specified needs and intended use, producing acceptable results under normal operating conditions Project: QMS18, MM17, QMS23, QMS01 Source: Quality Glossary NOTE 1: Performance qualification needs to be performed by laboratory personnel before use in testing and examinations; NOTE 2: Performance qualification should incorporate test cases and protocols to evaluate the full range of intended use; NOTE 3: Performance qualification represents the final qualification of the equipment; NOTE 4: Performance qualification must be performed by the organization’s personnel.
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performance specification a value or range of values for a performance characteristic, established or verified by the laboratory, that is used to describe the quality of patient test results (US CFR 493 February 28, 1992) Project: H26
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performance specifications a set of documented requirements to be satisfied by a particular method Project: MM09, MM17 NOTE: For laboratory methods, analytical performance characteristics are compared with performance specifications to determine whether the method’s performance is acceptable.
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performing laboratory the laboratory performing the test on the specimen or asset labeled or etched with a CLSI AUTO14 bar code Alternate Term: internal laboratory, in-house laboratory Project: AUTO14 NOTE 1: Performing laboratories might perform testing on internal or external specimens and assets; NOTE 2: Workflows in this standard are from the point of reference of the performing laboratory
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perfusion the presence of blood flow Project: POCT11
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pericardial fluid fluid that accumulates in the pericardium, a closed sac of tissue surrounding the heart, often due to inflammation or malignancy Project: C49 NOTE: The removal of such fluid is performed by pericardiocentesis.
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peridinin chlorophyll protein a fluorescent protein isolated from dinoflagellates, a family of unicellular algae that is commonly conjugated to monoclonal antibodies and used in flow cytometry applications and is commonly excited by a “blue” (488 nm argon) laser on many flow cytometers Project: I/LA26 NOTE: Peridinin chlorophyll protein is excited at approximately 490 nm with an emission maximum at 675 nm.
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peridinyl chlorophyllin a fluorochrome derived from the photosynthetic apparatus found in the dinoflagellate, Glenodinium Alternate Term: PerCP Project: H42 NOTE: Peridinyl chlorophyllin is a protein complex with a molecular weight of approximately 35 kDa. Peridinyl chlorophyllin has an excitation maximum around 490 nm, with an emission spectrum that peaks at 675 nm. Due to its photobleaching characteristics, peridinyl chlorophyllin conjugates are not recommended for use on stream-in-air flow cytometers and have been replaced in many applications by the tandem fluorochrome PerCP-Cy5.5 that is both brighter and has improved photostability.
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peritoneal dialysate fluid a physiologic synthetic fluid introduced into the peritoneal cavity for the purpose of normalizing fluid, electrolyte, and solute balance in the body using the principles of ultrafiltration and diffusion Project: H56
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peritoneal dialysis fluid fluid that is instilled into the abdominal cavity and then removed as a form of dialysis in patients with renal failure
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peritoneal fluid an ultrafiltrate of plasma in the peritoneal cavity Project: I/LA18
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peritoneal fluid a body fluid within the peritoneal cavity Project: H56
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peritoneal fluid fluid that accumulates in the peritoneal cavity of the abdomen, often due to hepatic cirrhosis and less frequently due to malignancy or cardiac failure Alternate Term: ascites, ascitic fluid Project: C49 NOTE: A subtype is peritoneal dialysis fluid – fluid that is instilled into the abdominal cavity and them removed as a form of dialysis in patients with renal failure.
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peritoneal lavage fluid a physiologic synthetic fluid introduced into the peritoneal cavity for the purpose of irrigating the cavity and removing the fluid for the purpose of examining its contents Project: H56
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permanent-stained smear fecal material (fixed or unfixed) spread onto a glass slide, which is subesequently stained (trichrome, iron-hematoxylin, modified acid-fast, modified trichrome, etc.) and examined microscopically using an oil immersion objective (total magnification of 1000x) Project: M28
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permeate substances passing through a semipermeable membrane Project: GP40
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peroxidase an enzyme commonly used in immunohistochemistry to label immunoreactive substances in cells and tissues Project: H56 NOTE: In immunohistochemistry, the reaction of peroxidase with an appropriate substrate-chromogen produces a colored reaction product that can be viewed microscopically.
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peroxisomal disorders a group of inherited metabolic diseases that result from defects in peroxisome assembly and/or proteins or enzymes located in the peroxisome Project: NBS09
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peroxisome a multifunctional subcellular organelle, which is present in virtually all eukaryotic cells and, in humans, has the main metabolic functions including β-oxidation of very long–chain fatty acids, bile acid synthesis, plasmalogen synthesis, α-oxidation of branched chain fatty acids, and detoxification of glyoxylate, hydrogen peroxide, and superoxide Project: NBS09
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personal data any information relating to an identified or identifiable natural person (“data subject”) Project: AUTO11 NOTE: For the purposes of CLSI AUTO11, this term is used to generically reference personally identifiable information and General Data Protection Regulation–defined personal data.
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personal digital assistant a class of portable, handheld consumer electronic devices that can manage calendars, contact lists, and task lists Alternate Term: PDA Project: POCT02 NOTE: This handheld device combines computing, telephone/fax, Internet, and networking features; a typical personal digital assistant can function as a cellular phone, fax sender, Web browser, and personal organizer.
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personal digital assistant the class of consumer electronic devices that handle functions such as management of calendars, contact lists, and task lists Project: POCT01 NOTE 1: Examples of personal digital assistants include the PalmTM and Pocket PCTM devices; NOTE 2: Please see Disclaimer Statement in the beginning of POCT01.
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personal identification number a character string used as a password to gain access to a system resource (RFC 2828) Project: AUTO09
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personal preparedness activities conducted to enhance personal and family communications and safety during an emergency Project: GP36
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personal protective equipment material, including clothing, used to prevent contamination of a person by chemical or biological matter (ISO 15190) Project: ISO15190, M29
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personal protective equipment protective clothing (eg, laboratory coats and gowns, hair and beard covers, shoe covers), goggles, face shields, respirators, or other garments designed to protect the wearer’s body from injury by blunt impacts, electrical hazards, heat, chemicals, and infection, for job-related occupational safety and health purposes Project: MM19, PRE05 NOTE: Personal protective equipment is also useful for enhancing a unidirectional workflow for pre–polymerase chain reaction samples and reagents.
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Personal Unblocking Key usually, each personal identification number code has an associated Personal Unblocking Key code that can be used to unblock the token if it becomes blocked as a result of entering several wrong personal identification number codes in a sequence Project: AUTO09
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personalized medicine the systematic use of information about each individual patient to select or optimize the patient’s preventive and therapeutic care NOTE: In genetics, an approach to medicine involving use of genomic and molecular data to better target health care, facilitate discovery and clinical testing of new products, and determine patient risk for a particular disease or condition.
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personally identifiable information any representation of information that enables the identity of an individual to whom the information applies to be reasonably inferred by either direct or indirect means Project: AUTO11 NOTE: For the purposes of CLSI AUTO11, personally identifiable information is also referred to as “personal data.”
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personnel collective group of employees and contractors hired by an organization Project: QMS16, QMS01 Source: Quality Glossary
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Petri net an abstract, formal model of information flow, showing static and dynamic properties of a system Project: AUTO08 NOTE: A Petri net is usually represented as a graph having two types of nodes connected by arcs, and markings indicating dynamic properties.
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pG See partial pressure.
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pH the symbol for the negative common logarithm of the relative molal hydrogen ion activity (αH+), which is a measure of the effective concentration of hydrogen ions in solution Project: C46 NOTE: Historically, pH arose as a symbol for the “power of hydrogen.”
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pH the symbol for the negative (decadic) logarithm of the {relative molal} hydrogen ion activity (αH+) (IFCCEPpH93) Project: C12, GP43, VET03 NOTE 1: The symbol is in such common use that it is considered the name of the concept; NOTE 2: It is used to express the acidity or alkalinity of a solution on a scale of 0 to 14; NOTE 3: The concept of pH is unique among physicochemical quantities in that it involves a single-ion activity that is experimentally immeasurable; because the activity of a single ionic species is a thermodynamically inexact quantity, the International Union of Pure and Applied Chemistry has adopted a conventional scale of pH, defined by reference buffer solutions with pH values that are assigned using a special electrochemical cell without liquid junction and containing a hydrogen-gas pH electrode and a silver/silver chloride reference electrode.
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pH-adjusted ionized calcium this calculated result empirically based on a measured pH and ionized calcium concentration, where the ionized calcium is normalized to a pH of 7.40 Project: C31 NOTE: These calculations exclusively compensate for in vitro increases in pH due to loss of CO2 and, therefore, help compensate for specimen handling errors; the pH-adjusted ionized calcium is automatically calculated by many of the commercial instruments currently available.
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pharmaceutical any synthetic substance or mixture of substances manufactured, sold, or represented for use in the diagnosis, treatment, mitigation, or prevention of a disease, disorder, abnormal physical state; restoring, correcting, or modifying organic functions in man; and which achieves its primary intended action in or on the human body by pharmaco¬logical, immunological, or metabolic means Project: HS11
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pharmacodynamics the relationship between the unbound drug concentration over time and the resulting antimicrobial effect Project: VET02, VET09, M23
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pharmacogenetic test the study of inherited differences (variation) in drug metabolism and response (see ICH Harmonised Tripartite Guideline E15) Project: MM20 NOTE 1: The analysis and interpretation of the effects of single or a small number of polymorphisms on a drug’s pharmacokinetic and pharmacodynamic properties in a given patient; NOTE 2: The study of variations in a DNA sequence as related to drug response.
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pharmacogenetics the study of inherited differences (variation) in drug metabolism and response Project: MM16
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pharmacogenetics 1) the study of inherited differences (variation) in drug metabolism and response; 2) the analysis and interpretation of the effects of single or a small number of polymorphisms on a drug’s pharmacokinetic and pharmacodynamic properties in a given patient Project: MM19
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pharmacogenomic test the analysis of the impact of many pharmacogenetic polymorphisms; collectively, pharmacogenomics is the whole genome application of pharmacogenetics, which examines the single gene interactions with drugs (see ICH Harmonised Tripartite Guideline E15) Project: MM20 NOTE: The study of variations of DNA and RNA characteristics as related to drug response.
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pharmacogenomics the general study of the many different genes that determine drug behavior Project: MM16
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pharmacogenomics the analysis of the impact of many pharmacogenetic polymorphisms; collectively, pharmacogenomics is the whole genome application of pharmacogenetics, which examines the single gene interactions with drugs Project: MM19
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pharmacokinetic/pharmacodynamic index the quantitative relationship between a pharmacokinetic parameter and a microbiological parameter (eg, minimal inhibitory concentration [MIC]) Project: VET09 NOTE 1: These parameters should be expressed in terms of the unbound fraction of total drug concentrations, regardless of the magnitude of protein binding observed with the specific moiety; NOTE 2: The most frequently used PK/PD indices are defined below: • f – prefix indicating that the PK parameter values or PK/PD index values are based on unbound (free) fractions of the drug. • fAUC:MIC – the area under the unbound drug concentration-time curve divided by the MIC, in which the MIC is measured according to a standard method; NOTE: Although this ratio has the dimension of hours, it is generally written as a dimensionless value within the literature. • fCmax:MIC – the peak unbound drug concentration divided by the MIC, in which the MIC is measured according to a standard method. • f(%T>MIC) – the percentage of time during a dosing interval that unbound drug concentrations exceed the MIC of the antimicrobial agent for the pathogen.
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pharmacokinetic/pharmacodynamic index the quantitative relationship between a measure of drug exposure such as area under the curve and a microbiological parameter such as minimal inhibitory concentration Project: M23
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pharmacokinetic/pharmacodynamic magnitude the numerical value of the pharmacokinetic/pharmacodynamic index Project: M23
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pharmacokinetic/pharmacodynamic target magnitude of the pharmacokinetic/pharmacodynamic index at which a desired nonclinical or clinical end point is achieved (eg, an area under the curve/minimal inhibitory concentration of X required to achieve a log10 reduction of Y) that is considered predictive of clinical response. Nonclinical or clinical pharmacodynamic end points may differ based on infection type Project: M23
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pharmacokinetics the study of the time course of drug absorption, distribution, metabolism, and excretion Project: VET02, M23, VET09 NOTE: PK parameters include drug concentrations, area under the curve (AUC), and peak concentration (Cmax). • AUC – the computed area under the curve that represents drug concentrations over time; NOTE 1: AUC24 is plasma or serum levels of a drug over a 24-hour interval after steady-state has been achieved, regardless of the number of doses during the 24-hour period; NOTE 2: For once-daily or more frequent dosing, AUC24 at steady state is equal to AUC0 estimated following a single administration of the same total dose if the PK are dose proportional. • Cmax – the maximum (or peak) concentration that a drug achieves in the compartment of reference (eg, blood); NOTE 1: Following drug administration, Cmax is generally estimated in terms of unbound drug concentration in plasma or serum; NOTE 2: Other approaches using total drug concentrations may be considered if scientifically justified; NOTE 3: PK parameters include drug concentrations, area under the curve (AUC), and peak concentration (Cmax).
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pharmakokinetics the study of the time course of drug absorption, distribution, metabolism, and excretion •AUC – the computed area under the curve that represents drug concentrations over time; NOTE 1: AUC24 is plasma or serum levels of a drug over a 24-hour interval after steady-state has been achieved, regardless of the number of doses during the 24-hour period; NOTE 2: For once-daily or more frequent dosing, AUC24 at steady state is equal to AUC0 estimated following a single administration of the same total dose if the PK are dose proportional.
•Cmax – the maximum (or peak) concentration that a drug achieves in the compartment of reference (eg, blood); NOTE 1: Following drug administration, Cmax is generally estimated in terms of unbound drug concentration in plasma or serum; NOTE 2: Other approaches using total drug concentrations may be considered if scientifically justified
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phase relative location of two or more heterozygous alleles respective to each other (ie, whether the variants are on the same strand or different strands) Project: MM09
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phase in EP19, a discrete milestone within a stage of the Test Life Phases Model Project: EP19 NOTE: For example, the Implementation Stage begins with the Preliminary Evaluation Phase. If that phase is acceptable, the laboratory proceeds to the Verification Phase.
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phasing breaking a construction project into pieces to allow work around occupied areas or to allow breakdown of costs into smaller units Project: QMS04
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phenotype the observable traits or characteristics of an organism, for example hair color, weight, or the presence or absence of a disease Project: MM10 NOTE: Phenotypic traits are not necessarily genetic (NHGRI).
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phenotype the observed biochemical, physiological, and/or morphological characteristics of a microorganism, often determined by the environment in which it is expressed Project: MM18 NOTE: In a more limited sense, the expression of some particular gene or genes.
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phenotype the observed biochemical, physiological, and/or morphological characteristics of an individual, as determined by the genotype and the environment in which it is expressed Project: MM12, MM01, ILA29, MM17, MM09, MM22, MM24 NOTE: Also, in a more limited sense, the expression of a particular gene or genes.
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phialide a structure with a terminal opening that produces conidia through enteroblastic conidiogenesis
Project: M54
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phishing an unauthorized method used to obtain financial or other confidential information from Internet users, typically by sending an e-mail that looks as if it is from a legitimate organization but contains a link to a nonlegitimate website that replicates a legitimate website Project: QMS22
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phlebotomy the act of drawing or removing blood from the circulatory system through a puncture to obtain a specimen for analysis and diagnosis Project: QMS04, GP48, PRE02
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phorbol 12-myristate 13-acetate a potent protein kinase C stimulatory substance (phorbol ester) often used in combination with ionomycin to stimulate T-cells to proliferate in a polyclonal manner Project: I/LA26 NOTE: Also termed 12-O-Tetradecanoylphorbol-13-Acetate.
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phosphorimager a device used to record the amount and intensity of a radioactive signal on a blotting membrane Project: MM02 NOTE: A phosphorimager may be used to replace film autoradiography.
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photodegradation irreversible photochemically-induced structural changes and accelerated decay of fluorochromes upon illumination that reduce or ablate fluorescence emissions; Project: I/LA24 NOTE: This term is synonymous with and in this document supersedes the terms "photobleaching" and "photodecomposition."
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photometer an instrument that measures the intensity of light emitted by, passed through, or reflected by a substance, usually by comparing the light from two sources, one of which has certain specified standard characteristics
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photometer a device designed to furnish the ratio, or a function thereof, of the radiant power of two electromagnetic beams; these two beams may be separated in time, space, or both. The instrument usually cannot isolate spectral bands narrower than 10 nm. Alternative terms used are “filter photometer” and “colorimeter” Project: H15
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photometry the measurement of the intensity of light emitted by, passed through, or reflected by a substance Project: POL1/2
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photo-optical method of clot detection technology by which absorbance of fibrin clot formation is measured at a particular wavelength Project: H48 NOTE 1: Clot detection is converted into an electronic signal, which is represented as proportional optical transmittance; NOTE 2: As the clot forms, light transmittance decreases and the end point isdetected (Koepke JA. Technologies for coagulation instruments. Lab Medicine. 2000;31(4):211-216).
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PHRED a base-calling program used to estimate the probability of error for each base call. (Available at: http://www.genome.washington.edu/UWGC/analysistools/Phred.cfm) Project: MM10
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PHRED score a quality value assigned to each called base, expressed as a log-transformed error probability Project: MM18 NOTE: PHRED quality values have been validated for both accuracy and power to discriminate between correct and incorrect base calls. PHRED scores are often provided by sequence base callers as confidence values for individual base calls; EXAMPLE: A quality score of 10 represents 1:10 probability the base is an error; a quality score of 20 represents a 1:100 probability the base is an error.
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phycoerythrin a large (≈ 240 000 molecular weight), water-soluble, fluorescent protein derived from various strains of red algae or cyanobacteria Project: I/LA26 NOTE 1: There are at least two types: B-phycoerythrin and R-phycoerythrin; the R-phycoerythrin type is more commonly used for flow cytometry; NOTE 2: Phycoerythrin is a member of a class of proteins known as phycobiliproteins, commonly excited by “blue” (488 nm argon) lasers but also has a second excitation line at approximately 565 nm. Phycoerythrin is commonly excited at approximately 480 nm with an emission maximum at 578 nm.
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phycoerythrin one of several phycobiliprotein-based fluorochromes, derived from algae or bacteria, which can be conjugated to antibodies for use in immunophenotyping Alternate Term: PE Project: H42, H43, H52 NOTE 1: Phycoerythrin has a molecular weight of 240 kD. Although it absorbs light maximally at 545 nm, there is sufficient absorption at the 488-nm excitation to provide a usable signal in the red/orange (575 nm) emission range when excited by an argon laser; NOTE 2: Denaturation of phycoerythrin does not cause a spectral shift, but instead quenches the fluorescence. Aggregation of phycoerythrin/immunoglobulin conjugates causes nonspecific binding.
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phylogenetic tree a graphical representation of the estimate of the evolutionary relationships between taxa or genes Project: MM10, MM24
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phylogeny the evolutionary history of an organism group Project: MM18 NOTE: Any group of species is descended from a common ancestral species, which, over time, split into two species, with these descendents splitting again, and again, until the entire collection of species was produced through evolution and speciation. The genealogical connections thereby formed in general take the shape of a tree, called the phylogeny of the group.
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physical control quality control device that does not include chemically reactive components, that is intended by the manufacturer to verify the performance of the monitor (modified from ISO 17593) Project: ISO 17593 (January 2002) NOTE 1: The physical control may be in the form of an electronic device that provides a simulated reaction (modified from ISO 17593). NOTE 2: The physical control result must meet predefined limits in order for the monitor to be considered properly functional (modified from ISO 17593).
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physical control system control device that does not include chemically reactive components and that is intended by the manufacturer to verify the performance of the instrument (ISO 17593) Project: ISO 17593 NOTE 1: The physical control system may be in the form of an electronic device that provides a simulated reaction (ISO 17593); NOTE 2: The physical control result must be within predefined limits in order for the measuring system to be considered properly functional (ISO 17593).
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physical separation measurement procedures measurement procedures that employ a physical separation of the free and protein-bound hormone in the specimen Project: C45 NOTE 1: Approaches typically used are based on separation across a membrane (eg, in dialysis or ultrafiltration), gel-filtration/bead analysis or gel adsorption, followed by direct quantitation of hormone in the free fraction by a sensitive measuring technique (eg, immunoassay); NOTE 2: Strictly speaking, immunoextraction also falls under this definition.
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physicochemical interference an environmental or structural difference from that of the patient specimens that causes a difference between the population mean of the test results and an accepted reference value due to a change in the measured physical chemical property; NOTE: This is what has commonly been referred to as “matrix effect”; examples include the effect of different protein matrices on bilirubin spectra or the impact of proteins and lipids on the measurement of electrolytes in plasma in direct ion-selective electrode systems. See also Analytical interference
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physiological lag the extent to which the observed lag time reflects the difference in glucose concentration from venous or capillary blood to the medium being sampled by the sensor (eg, interstitial fluid)
Project: POCT05 NOTE: Because glucose transport goes in both directions across cellular membranes, it is possible that the glucose concentration of the interstitial fluid could increase or decrease before the blood glucose changes.
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physiological range the full range of analyte levels to be expected in patient samples Project: VET03, VET04
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physiology study of functions of living organisms Project: GP48
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phytohemagglutinin a mitogenic plant agglutinin isolated from red kidney beans (Phaseolus vulgaris) often used in in vitro T-cell stimulation assays Project: I/LA26
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pictogram symbol plus other graphic elements intended to convey specific information about the hazards of the chemical (see A Guide to the Globally Harmonized System of Classification and Labelling of Chemicals [GHS]) Project: GP17 NOTE: Each pictogram consists of a different black symbol on a white background within a red diamond border.
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PID in Automation, an Health Level Seven abbreviation for Health Level Seven patient identification segment (HL7 V2.6) Project: AUTO01, AUTO02, AUTO03
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pipette a universal laboratory device for the volumetric measurement and transfer of fluids from one container to another Project: ISO15190 (March 2002)
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pitch the center distance between two specimen containers in a carrier or between two sequential specimen container carriers Project: AUTO01, AUTO02
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pK' the symbol used almost exclusively to represent the concept negative decadic logarithm of the apparent dissociation constant, quantitatively defined under specified conditions NOTE: For example, of the bicarbonate-carbonic acid equilibrium in plasma.
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pK' the symbol used to represent the negative common logarithm of the apparent dissociation constant quantitatively defined under specified conditions Project: C46
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PKIX 1) a contraction of “Public-Key Infrastructure (X.509),” the name of the Internet Engineering Task Force working group that is specifying an architecture and set of protocols needed to support an X.509-based public-key infrastructure for the Internet; 2) A collective name for that architecture and set of protocols (RFC 2828) Project: AUTO09
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placer in Automation, a person or service that requests observations Project: AUTO01, AUTO02, AUTO03 NOTE: An example would be the physician, the practice, the clinic, or ward service that orders a test, x-ray, or vital signs.
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placer group number the unique pair of identifiers assigned to an order group by the order placer actor on the ward side and by the order filler actor on the laboratory side Project: AUTO16 NOTE: Either of the two identifiers may be present, or both may be present.
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placer order number the unique reference assigned to an order by the order placer actor Project: AUTO16
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plaintext data that is input to and transformed by an encryption process, or that is output by a decryption process (RFC 2828) Project: AUTO09
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plan written account of intended future course of action aimed at achieving a specific goal(s) or objective(s) within a specific time frame that explains in detail what needs to be done, when, how, and by whom Project: GP26, QMS06, QMS16, QMS21, QMS14, QMS25, QMS01 Source: Quality Glossary NOTE: May be referred to as an action plan.
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planktonic a term used to describe aquatic microorganisms that float Project: GP40
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planning and programming first design phase of a construction project, in which the general project requirements are detailed, such as specific areas, square footage requirements, budgets, relationships, and equipment Project: QMS04
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Plans Management Program an anticipatory planning process that establishes the effective and efficient short-, medium-, and long-range plans to satisfy the most important customer needs. A plan consists of a combination of strategies, goals, and objectives that will satisfy prioritized customer-supplier needs, now and into the future
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plasma in vivo, the liquid portion of whole blood that does not contain cells; in vitro, the liquid portion of anticoagulated whole blood that does not contain cells Project: POCT13, POCT14, POCT17, POCT04 NOTE: If a chemical agent or anticoagulant is added to prevent clotting, a blood sample can be separated by centrifugation into cells and a plasma supernatant.
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plasma in vitro, the liquid portion of anticoagulated whole blood that does not contain cells Project: C56
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plasma equivalent (result) a glucose result obtained from a whole blood glucose meter system that is calibrated to yield a result from the same sample that is equivalent to the result obtained with plasma that has been separated from the cellular components and measured on a laboratory analyzer Project: POCT12 NOTE: At nominal (43%) hematocrit, this value will be approximately 11% higher than the whole blood concentration.
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plastic laminate a hard-surfaced, thin material made from melamine under high pressure and used for the finished surfaces of countertops, cabinets, and furniture Project: QMS04
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plasticizer a chemical component of plastics to make them softer and more flexible Project: GP40
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plate number a number of theoretical plates in a chromatographic column reflecting the efficiency of the column and calculated using the following equation: N = 5.545(VR/w1/2h),2 where VR is the retention volume and w1/2h is the peak width at half height; NOTE: When calculating Rs and N, the units must be consistent so that their ratio is dimensionless; ie, if the numerator is a volume, then peak width must also be expressed in terms of volume Project: C43 NOTE: When calculating Rs and N, the units must be consistent so that their ratio is dimensionless; ie, if the numerator is a volume, then peak width must also be expressed in terms of volume.
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platelet agglutination the clumping of intact or fixed platelets by von Willebrand factor in the presence of ristocetin Project: H51
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platelet agglutination the clumping of intact or fixed platelets by von Willebrand factor in the presence of ristocetin Project: H51
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platelet aggregation platelet clumping, largely mediated by fibrinogen binding to the platelet receptor, GPIIb/IIIa, following activation of intact platelets by soluble agonists such as adenosine diphosphate (ADP) and thrombin, or particular agents such as a suspension of collagen, or sheer stress Project: H51
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platelet aggregometer platelet clumping, largely mediated by fibrinogen binding to the platelet receptor, GPIIb/IIIa, following activation of intact platelets by soluble agonists such as adenosine diphosphate (ADP) and thrombin, or particular agents such as a suspension of collagen, or sheer stress Project: H51
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platelet aggregometer a device that measures changes in light transmission through a suspension of platelets; NOTE: As platelets clump, more light passes through the suspension, and the increase in light transmission is recorded continually Project: H51
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platelet aggregometer a device that measures changes in light transmission through a suspension of platelets Project: H51 NOTE: As platelets clump, more light passes through the suspension, and the increase in light transmission is recorded continually.
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platelet-poor plasma plasma that has been depleted of platelets by high g force (relative centrifugal force) centrifugation Alternate Term: PPP Project: H58
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platelet-poor plasma centrifuged citrated plasma sample with a platelet count of < 10 × 109/L Project: H60, H21
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platelet-rich plasma plasma containing platelets that is prepared by low g force (relative centrifugal force) centrifugation of whole blood Alternate Term: PRP Project: H58
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platform technology behind a flow cytometric application, usually in reference to a suite of instrumentation or analysis software; may include reagents from a vendor Project: H62
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platform instrumentation that integrates multiple operations for the purpose of generating a specific result(s), typically using a process accompanied by a defined series of steps Project: MM09 NOTE: In next-generation sequencing, the “platform” typically refers to the instrumentation that analyzes a sample and produces digital sequencing data. In most cases, these data require additional analysis using an informatics pipeline to construct and annotate a single or a set of contiguous sequences that is clinically meaningful.
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player individual with active role in preventing, responding to, or recovering from the risks and hazards presented in an exercise scenario, by either discussing (in a discussion-based exercise) or performing (in an operations-based exercise) his or her regular roles and responsibilities Project: GP36 NOTE: Players initiate actions that will respond to and/or mitigate the simulated emergency.
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pleural fluid fluid that accumulates in the pleural cavity surrounding the lungs Alternate Term: pleural effusion Project: C49 NOTE 1: The accumulation of such fluid is known as pleural effusion; NOTE 2: The removal of such fluid is performed by thoracentesis; NOTE 3: Various subtypes of pleural fluid include: • exudate – due to inflammation and characterized by high protein and presence of cells. • transudate – due to changes in hemodynamic pressures, typically paucicellular and low in protein; often seen in congestive heart failure
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pleural fluid the serous fluid within the pleural cavity Project: H56
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PMA acronym for premarket application submission of a Class III device to FDA
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POC device interface specifies the interface (principally output) of a point-of-care device or its docking station to an access point Project: POCT01 NOTE: This definition is equivalent to IEEE “device communication controller.”
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point accuracy closeness of agreement between a glucose test result and an accepted reference value at single points in time Project: POCT05
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point estimate a value that summarizes a set of data without accounting for the precision of the estimate (eg, its uncertainty)
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point in space See point of reference Project: AUTO02
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point of care the health care environment immediately surrounding a patient Project: POCT02, POCT08, M53, POCT15 NOTE: Examples include bedside on a medical unit, operating room, ambulance or mobile transport vehicle, and physician’s office.
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point of care the environment immediately surrounding a patient Project: POCT01
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point of reference the intersection of the xy plane and an infinite line in the ‘z’ direction Project: AUTO01, AUTO02 NOTE: The point of reference is the reference from which all positioning and alignment of specimen containers is measured.
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point-of-care activated partial thromboplastin time activated partial thromboplastin time performed using a point-of-care testing system Project: POCT14
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point-of-care coagulation testing any coagulation test performed using a point-of-care testing system Project: POCT14
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point-of-care connectivity devices devices with the ability to link point-of-care devices to each other, to laboratory information systems, or both Project: POCT07
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point-of-care coordinator an individual who has overall responsibility for ensuring that the operation of all point-of-care devices in the institution is compliant with the institution’s point-of-care quality system Project: POCT01 NOTE: The services provided by the data manager(s) in the system are key tools used by the point-of-care coordinator to assure compliance.
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point-of-care coordinator an individual who, under the direction of the laboratory director, has overall responsibility for ensuring that the operation of all point-of-care testing and activities related to point-of-care testing is compliant according to regulatory standards and the institution’s processes, policies, and procedures Project: POCT07
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point-of-care coordinator an individual who has overall responsibility for ensuring the quality of observations or test results conducted by point-of-care testing devices in an institution, including the analytical performance of the device, the competence of the operators, and other aspects of operating the device in compliance with an institution’s quality assurance system Project: POCT02, POCT08, POCT15
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point-of-care device in the context of POCT01, a point-of-care device is an instrument used at the patient’s side to measure and/or record a clinical observation Project: POCT01 NOTE: This definition does not require that the point-of-care device measure the observed value; thus, this definition encompasses devices that perform biochemical analyses, devices that calculate observations from results determined externally, or devices that simply record values determined by other procedures.
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point-of-care prothrombin time/international normalized ratio prothrombin time and international normalized ratio performed using a point-of-care testing system Project: POCT14
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point-of-care screening in vivo monitoring or testing of physiological parameters performed in a hospital, clinic, ambulatory health care facility, or other alternate site outside a central laboratory environment, generally nearer or at the site of the patient Project: NBS03, NBS02 Source: Newborn Screening Glossary NOTE: As applied to newborn screening, “point-of-care screening” describes practices in which results are obtained at the bedside, with oversight from a public health agency, to detect diseases specified for a jurisdiction (eg, hearing screening, pulse oximetry for critical congenital heart disease detection).
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point-of-care testing 1) testing that is performed near or at the site of the patient with the result leading to possible change in the care of the patient (ISO 22870); 2) testing performed outside a central or satellite laboratory environment, generally nearer to, or at the site of, the patient or client Alternate Term: near-patient testing; alternative-site testing; bedside testing Project: ISO 22870, POCT04, C52, EP18, POCT09, POCT07, POCT08, POCT12, I/LA20, C63, POCT15, NBS10 NOTE 1: Point-of-care testing is the performance of diagnostic tests at the point of care (eg, bedside, outpatient clinic, community pharmacy, or home); NOTE 2: These tests are often miniaturized handheld devices that produce a rapid analytical result with less-than-ideal analytical sensitivity and quantitation; NOTE 3: Alternate terms include “decentralized testing,” “ancillary testing,” “patient-focused testing,” “satellite testing,” and “peripheral testing”; NOTE 4: These tests are often miniaturized handheld devices that produce a rapid analytical result with less-than-ideal lower limit of detection and lower limit of quantitation; NOTE 5: Point-of-care newborn screening describes practices in which results are obtained at the bedside for the detection of diseases specified for a jurisdiction, which may or may not have oversight from a public health agency.
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point-of-care testing testing performed outside a central laboratory environment, generally nearer to or at the site of the person being tested Alternate Term: bedside testing; near-patient testing Project: POCT13, POCT18, POCT17
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point-of-care testing testing performed in an alternate site, outside a central laboratory environment, generally nearer to or at the site of the patient Alternate Term: bedside testing; near-patient testing Project: POCT14, EP31 NOTE: This type of testing usually results in more rapid turnaround time. The importance of the clinical decision is subjective by situation.
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point-of-care testing device in the context of this standard, a point-of-care testing device is an instrument that measures and/or records a clinical observation (a test result); the device may be located at or close to the patient’s bedside or may be at a more remote location to which the specimen is sent for evaluation Project: POCT02 NOTE: This definition does not require that the point-of-care testing device measure the observed value; thus, this definition encompasses devices that perform biochemical analyses, calculate observations from results determined externally, or simply record values determined by other procedures.
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point-of-care testing device a tool used to detect the presence of a specific analyte Project: POCT08, POCT15 NOTE: Examples include a test cartridge (eg, urine pregnancy), a test strip (eg, urinalysis dipstick), a test kit (eg, rapid strep kit), a testing instrument system (eg, molecular influenza test), and others.
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Point-to-Point Protocol an Internet Standard protocol for encapsulation and full-duplex transportation of network layer (mainly Open System Interconnection layer 3) protocol data packets over a link between two peers, and for multiplexing different network layer protocols over the same link. Includes optional negotiation to select and use a peer entity authentication protocol to authenticate the peers to each other before they exchange network layer data (RFC 2828) Project: AUTO09
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Point-to-Point Protocol a protocol for framing Internet Protocol datagrams over a serial line Project: POCT01
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Poisson distribution a distribution in statistics that is a good approximation to the binomial distribution when the probability of success in a single trial is very small and the number of trials is very large Project: I/LA26
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Poisson distribution In contrast to the gaussian (normal) distribution, which describes common events occurring about a mean and diminishing rapidly in frequency at the symmetrical tails, the Poisson distribution describes rare events; therefore, it is suitably applied to blood cell counting, in which minute particles are randomly distributed with a very large volume of fluid, and also to microscopic differential counts, in which leukocytes are considered rare particles randomly distributed over an infinitely large surface. The relevance is that imprecision standard of deviation is calculated differently between the two types of distributions, as follows: Gaussian: SD = √∑(x - x-bar)2 divided by n - 1 where SD = standard deviation
x = individual observation
x-bar = mean of all observations
n = number of observations
Poisson distribution: SD = √n Where n = number of cells enumerated by the device, not the resultant final concentration. Obtain those values from the manufacturer because they are usually not apparent to the end user. Because the calculation of imprecision is the same for both, hematology analyzers yield smaller percent coefficient of variation as more white blood cells, red blood cells, and platelets are counted by the sensing mechanisms, usually as a function of smaller blood dilutions and longer counting times Project: H26
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policy a written statement of overall intentions and directions defined by those in the organization and endorsed by management (AABB) Project: I/LA33 NOTE: A documented general principle that guides present and future decisions.
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policy intentions and direction formally expressed within an organization and endorsed by laboratory leadership Project: QMS02, QMS06, QMS16, QMS21, QMS25, QMS01 Source: Quality Glossary
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polishing in water purification systems, the final treatment stage(s) of the purification system Project: GP40
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polyclonal antibody mixture of antibodies capable of reacting specifically with a certain immunogenic substance (modified from ISO 19001) Project: ISO 19001, I/LA28 NOTE 1: Polyclonal antibody is a mixture of antibodies derived from different clones and thus having different specificities; NOTE 2: Antiserum produced by immunization of intact animals is usually polyclonal.
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polymerase chain reaction a common method of DNA amplification, using pairs of oligonucleotide primers as start sites for repetitive rounds of DNA polymerase–catalyzed replication and alternating with denaturation in successive heating-cooling cycles Project: MM09, MM12, POCT15
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polymerase chain reaction a technology used to synthesize multiple copies of a defined region of target DNA Project: I/LA18, MM10, MM22, NBS05, MM24 NOTE: A common method of DNA amplification using pairs of oligonucleotide primers as start sites for repetitive rounds of DNA polymerase-catalyzed replication alternating with denaturation in successive heating-cooling cycles.
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polymerase chain reaction a common method of enzymatic DNA amplification, using pairs of oligonucleotide primers to form short double-stranded DNA regions to serve as initiation sites for DNA polymerase-catalyzed replication alternating with denaturation in successive, repetitive rounds of heating-cooling cycles to achieve denaturation, annealing, and extension Project: MM01
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polymerase chain reaction a method for producing multiple copies of a segment of genomic DNA or coding DNA to test for the presence or expression of the sequence of the gene of interest or to obtain adequate amounts of the sequence of interest for additional analysis Project: MM05
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polymerase chain reaction the two-fold exponential production of a DNA sequence through the repeated thermal cycling of a mixture containing: 1) genomic DNA or complementary DNA derived from RNA (template); 2) a heat-stable DNA polymerase; 3) primer oligonucleotides that complement the 3' (forward) and 5' (reverse) sequences flanking the targeted sequence; and 4) deoxynucleoside triphosphates and other components essential to the reaction Project: NBS06 NOTE 1: Polymerase chain reaction is often referred to as “amplification” and the accumulated copies of a particular DNA sequence as the “amplicon”; NOTE 2: Several variants of polymerase chain reaction are used for preparation and analysis of targeted DNA sequences. End-point polymerase chain reaction repeats thermal cycling to a predetermined amplification cycling number without monitoring each thermal cycle. It is widely used to prepare targeted DNA sequence for subsequent analysis such as sequencing and gene mutation detection but it is generally not used as a quantitative assay unless the end-point accumulation of the targeted DNA sequence lies within the valid dose-response range. Real-time polymerase chain reaction monitors the reaction at each thermal cycle, recording the cycle-by-cycle accumulation of amplicon. Assay conditions for real-time polymerase chain reaction can generally be adjusted so that the accumulated product has a log-linear relationship with cycle number in the mid-range of the reaction (generally somewhere between 15 and 35 cycles). Quantitative polymerase chain reaction is any polymerase chain reaction used to measure the original content of a template DNA sequence, either as proportionate values relative to other sequences or as absolute values expressed as copy numbers (sometimes called absolute quantitative polymerase chain reaction). Real-time polymerase chain reaction is the most frequently used format for quantitative polymerase chain reaction, but other variants such as single-point polymerase chain reaction, competitive polymerase chain reaction, and digital polymerase chain reaction can also be used for quantitation. Single-point quantitative polymerase chain reaction (also called end-point quantitative polymerase chain reaction) does not monitor the reaction at each cycle, but measures accumulation at one point within the linear relationship between log accumulated product and cycle number. Competitive quantitative polymerase chain reaction is a variant of single point polymerase chain reaction that uses a known concentration of a second DNA target with a similar sequence to the template DNA target as an internal standard to quantify production of the template amplicon. Digital polymerase chain reaction separates the template sample into a large number of partitions, and the polymerase chain reaction is carried out in each partition individually. In the dilution range where some partitions do not contain any copies of the template, the partitioning of the sample allows one to count the template molecules by estimating according to Poisson distribution. This estimate gives an absolute count of template copies without reference to any independent standard, and its accuracy may be improved in principle to any desired level by counting more partitions; NOTE 3: The abbreviation “RT PCR” is not used in this document because it is ambiguously applied to both “real-time polymerase chain reaction” and “reverse-transcriptase polymerase chain reaction.”
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polymerase chain reaction ribotyping a molecular technique for bacterial identification and characterization that uses information from rRNA-based phylogenetic analyses Project: MM24 NOTE: A common method of DNA amplification, using pairs of oligonucleotide primers as start sites for repetitive rounds of DNA polymerase-catalyzed replication alternating with denaturation in successive heating-cooling cycles.
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polymicrobic marked by the presence of several species of microorganisms Project: M56
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polymorphism a common variation within the sequences of an organism having multiple copy genes resulting in areas with ambiguous bases Project: MM18
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polymorphism a common variation in the sequence of DNA among individuals resulting in the occurrence together in a population of two or more alternative genotypes, each at a frequency greater than that which could be maintained by recurrent mutation alone Project: MM10, MM12, MM17, MM22, MM01, MM24 NOTE: A locus is arbitrarily considered polymorphic if the rarer allele has a frequency ≥ 0.01, so the heterozygote frequency is at least 0.02.
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polymorphism in population genetics, a DNA sequence alteration that has a frequency of at least 1% in the general population Project: NBS05 NOTE: In medical genetics, the term polymorphism is often incorrectly used as a synonym for nondisease-causing variant.
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polynomial regression a least-squared regression using polynomials of various orders:
Y = a + b1x (first-order polynomial or linear fit)
Y = a + b1X + b2X2 (second-order polynomial), and
Y = a + b1X + b2X2 + b3X3 (third-order polynomial)
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polyvinyl chloride (PVC) a plastic that can be used as edging material, e.g., in countertops or in plumbing applications
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Pompe disease an autosomal recessive lysosomal storage disorder (also known as glycogen storage disorder II and acid maltase deficiency) in which acid α-glucosidase deficiency leads to intralysosomal accumulation of glycogen in all tissues, most notably in cardiac and skeletal muscle Project: NBS07 NOTE: Pompe disease shows considerable variability in severity and age of onset (Online Mendelian Inheritance in Man (OMIM®). #232300 Glycogen storage disease II; GSD2. http://www.omim.org/entry/232300)
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pooled dataset minimal inhibitory concentration/minimal effective concentration susceptibility values collected according to reference method criteria and combined from multiple laboratories Project: M57
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pooled within-run variance the overall within-run variance Project: EP10 NOTE: In the CLSI EP10 procedure, because all the days have the same number of data points, the daily within-run variances are averaged.
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poor-quality spectrum a spectrum with few resolved peaks and low signal-to-noise Project: M58
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population the totality of items under consideration Alternate Term: study group Project: I/LA21 NOTE: The study group is the sample subset of the population which is actually studied.
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population the totality of items under consideration (ISO 3534-1-2.3) Alternate Term: study group Project: ISO 3534-1-2.3 NOTE: The study group is the subset of the population which is actually studied (ISO 3534-1).
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pop-up fatigue lassitude that develops after encountering too many alerts or other clinical decision support tools, which often results in the clinician or ordering provider simply closing the alert without reading the contents Project: GP49
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POR abbreviation for point of reference Project: AUTO02
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portability the ease with which a system or component can be transferred from one hardware or software environment to another Project: AUTO08
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positive control (PC) a sample/mock sample that should yield a predictable result because it contains a known quantity of the analyte under test Alternate Term: PC Project: ILA29 NOTE: It is a method or validity check to ensure the method is performing as intended.
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positive cutoff the quantitative value of a measured analyte that is used to determine that a result is above a clinical or analytical decision point and therefore positive Project: ILA29
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positive likelihood ratio the ratio between the probability that the test will be positive when the reference standard (gold standard) is positive vs the probability that the test will be positive when the reference standard (gold standard) is negative NOTE: Positive likelihood ratio tells how many times more likely the subjects with the target condition are to have a positive result than subjects without the target condition. (The ratio of the sensitivity to the false-positive rate, Sensitivity/[1-Specificity] when there is a gold standard value.)
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positive percent agreement the test method’s ability to obtain positive results in concordance with positive results obtained by the comparative method, expressed as percentage of agreement Project: MM17, MM09 NOTE: The proportion of correct calls by the assay for the presence of a measurand.
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positive percent agreement the percentage of agreement between positive test results with the positive results of the comparative method (usually nonreference standard); the percentage of agreement of the test method’s ability to obtain positive results in concordance with positive results obtained by the reference method Project: MM01
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positive percent agreement the proportion of comparative method positive results in which the test method result is positive when the comparative method is not a widely accepted best method of assessing a target condition Project: EP19, EP12
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positive percent agreement concordance compared with positive results from a comparator assay (nondiagnostic) Project: H62
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positive predictive value (of newborn screening) the probability that an individual with a screen-positive result has a program-defined target disease Project: NBS09, NBS05, NBS10 Source: Newborn Screening Glossary NOTE 1: Positive predictive value = a / (a + b), for which a = confirmed cases that were screen positive (ie, true-positive screening test results) and b = any screen-positive results for which additional follow-up showed that the newborn does not have the program-defined target disease (ie, false-positive screening test results); see table in screening outcome; NOTE 2: A program might report multiple positive predictive values, depending on which disease, group of diseases, and/or other medically relevant findings are defined and included as true-positive or false-positive screening test results; NOTE 3: See screening outcome.
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positive predictive value chance that the patient does have the condition or disorder if the test result is positive
Alternate Term: predictive value of a positive result Project: H62 NOTE 1: Predictive value of a positive result is the percentage (number fraction multiplied by 100) of subjects with a positive test result who have the target condition (as determined by the diagnostic accuracy criteria); NOTE 2: Predictive value of a positive result must be interpreted in context with the prevalence of the condition of interest (as determined by the diagnostic accuracy criteria); NOTE 3: An estimate of predictive value of a positive result [with estimated prevalence equal to 100 × (TP + FN)/(TP + FP + FN + TN)] is calculated as 100 × TP/(TP + FP).
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positive predictive value in the context of this guideline, the likelihood that an individual with a test result above one or more defined thresholds has a particular disease, is at risk for a disease, or is at risk for a specific characteristic or outcome that the test is designed to detect Project: MM06 NOTE: Positive predictive value = true-positive results / (true-positive results + false-positive results).
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positive predictive value the proportion of patients with positive test results who have the target condition (as determined by the reference standard) Project: MM17, MM09 NOTE 1: Positive predictive value must be interpreted in context of the prevalence and penetrance of the condition of interest (as determined by the reference standard); NOTE 2: An estimate of positive predictive value is calculated as 100 • true positives / (true positives + false positives); NOTE 3: If the test is 100% specific, then positive predictive value = 100% (all subjects with positive test results have the target condition); NOTE 4: The likelihood that an individual with a positive test result has a particular disease or characteristic that the test is designed to detect.
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positive predictive value the probability that a positive test result represents disease Project: H20 NOTE: It is the fraction of true positive results over all positive results (true positives/true positives + false positives).
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positive predictive value probability of being affected given a positive result expressed as a proportion or percentage, ie, the number of true-positives divided by the total number of positives (true and false) Project: I/LA25
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positive predictive value the likelihood that an individual with a positive test result has a particular disease or other characteristic that the test is designed to detect Project: H59, MM01, MM22, MM12, MM23, I/LA21, I/LA23, POCT15 NOTE 1: The positive predictive value varies with the prevalence of the disease in the population tested; NOTE 2: From predictive value theory, the proportion of positive tests that are true positives; NOTE 3: The positive predictive value varies with prevalence of the disease unless the test is 100% specific; NOTE 4: A locus is arbitrarily considered to be polymorphic if the rarer allele has a frequency of 0.01, so that the heterozygote frequency is at least 0.02; NOTE 5: Positive predictive value = true positive / (true positive + false positive).
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positive pressure room pressure above that of an adjacent space, causing air to flow out of the room into the adjacent space
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positive result a test result above the cutoff value Project: C52, C63
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positivity See hit rate. Project: EP17
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postamplification the analytical steps that follow a polymerase chain reaction that allow characterization of the amplified patient sample Project: MM19
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postanalytical activities to be done after a test has been performed; documenting the results on the patient’s chart (a paper or electronic medical record), as well as reporting the results to the health care provider, and even clinical utilization of a test result Project: POCT08 NOTE: The ISO standard term is “postexamination.”
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postanalytical process See postanalytical procedures Alternate Term: postanalytical procedures Project: HS02
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postanalytical/postexamination processes processes following the examination, including review of results, retention and storage of clinical material, sample (and waste) disposal, and formatting, releasing, reporting, and retention of examination results (ISO 15189) Project: POCT10
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postantibiotic sub–minimal inhibitory concentration effect the effect of sub–minimal inhibitory concentration drug concentrations on bacterial growth following exposure to drug concentrations exceeding the minimal inhibitory concentration Project: VET02
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postcentrifugation phase the time period after the centrifuging of the specimen and before removal of an aliquot of serum or plasma for testing
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posterior probability the probability that the test result reflects the disease state or characteristic associated with a particular subject. See also Predictive value and Pretest probability Project: GP10
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postexamination processes following the examination, including review of results, retention and storage of clinical material, sample (and waste) disposal, and formatting, releasing, reporting, and retention of examination results (ISO 15189) Project: PRE01, EP23, GP33
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postexamination process See postanalytical procedures Alternate Term: postanalytical procedures Project: HS02
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postexamination processes processes following examination, including review, release, reporting, and retention of results and retention, storage, and disposal of clinical material (modified from ISO 15189) Project: GP26, QMS25, GP23, QMS22, QMS01 Source: Quality Glossary
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postimplementation after or following implementation Project: I/LA33
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postintervention all processes that follow the intervention Project: QMS07
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postprocedure all processes following medical imaging services, including patient assessment, instruction, and follow-up, and documentation and results reporting
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postproduction part of the life-cycle of the product after the design has been completed and the medical device has been manufactured and released (ISO/DIS 14971) Project: ISO/DIS 14971 EXAMPLES: transportation, storage, installation, product use, maintenance, repair, product changes, decommissioning and disposal
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postservice all processes following inpatient pharmacy services, including medication administration, and patient monitoring
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posttest all processes that follow the test Project: QMS07
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postzone effect the increased solubility of immune complexes resulting from the presence of a marked excess of antigen in relationship to antibody concentration. See also Prozone effect Project: DI01, I/LA23
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potable water water that meets regulations as suitable for ingestion by humans Project: GP40
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potency (for antimicrobial agent properties) antimicrobially active fraction of a test substance, determined in a bioassay against a reference powder of the same substance (ISO 20776-1) Project: ISO 20776-1 NOTE: The potency is expressed as mass fraction in milligrams per gram (mg/g), or as activity content in International Units (IU) per gram, or as a volume fraction or mass fraction in percent, or as an amount-of-substance concentration (mass fraction) in mole per liter of ingredients in the test substance (ISO 20776-1).
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potency In Immunologic Testing, the characteristic of an antibody that represents the concentration of antibody and the avidity for a given substrate antigen in a defined method Project: I/LA23
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potency the characteristic of an antigen solution that represents the concentration of the antigen in a defined method
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potentially infectious materials See other potentially infectious materials Alternate Term: other potentially infectious materials Project: M29
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potentiator a reagent solution added to or already incorporated into a testing platform to enhance in vitro antibody-antigen reactions Project: I/LA33
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potentiometry a technique whereby the electromotive force (potential difference) of a cell can be related by means of the Nernst Equation to the activity of a single, desired species in solution Project: C39
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povidone-iodine a water-soluble complex of iodine with polyvinylpyrrolidone Project: M47 NOTE: Used as a topical agent for disinfecting the skin.
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power 1) the ability of a study to demonstrate an association if one exists; 2) a characteristic of a statistical hypothesis test, denoting the probability that the null hypothesis will be rejected if it is indeed false; 3) the probability that a trial will detect, as statistically significant, an intervention effect of a specified size Alternate Term: statistical power Project: GP45 NOTE 1: The power of a study is determined by several factors, including the frequency of the condition under study, the magnitude of the effect, the study design, and sample size; NOTE 2: Mathematically, power is 1-β (Type II error); NOTE 3: The prespecified trial size is often chosen to give the trial the desired power.
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power probability of rejecting the null hypothesis when it is false Project: EP07, EP31 NOTE: The probability is usually denoted as a percentage, 100(1 − β)%.
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power of error detection the statistical probability that a quality control system will detect changes that exceed defined limits Project: QMS24 NOTE: Generally, two types of changes are considered: (i) imprecision measured in multiples of the standard deviation and (ii) bias measured in absolute units.
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power output of the magnetron a measure of heat per unit time, ie, 1 W = 14.33 cal/min Project: GP28 NOTE: The micowave energy output from the magnetron is generally measured in watts.
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practice parameters strategies for patient management developed to assist medical professionals in clinical decision-making Project: I/LA20 NOTE: Practice parameters may also be called practice options, practice guidelines, practice policies, or practice standards. They are documents that define, from the perspective of the health care provider, effective means of diagnosing, treating, and managing various conditions and diseases. They are usually based upon literature review (scientific research in the form of randomized, controlled clinical trials, reports of series, or case studies) or “expert clinical experience and opinions.” They are prepared by individuals with expertise in the field.
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preamplification those activities that precede the actual polymerase chain reaction, including reagent preparation and nucleic acid extraction Project: MM19
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preanalytical activities performed before performing the patient test; verifying the clinician’s order, properly identifying the patient, patient preparation, and collection of the sample Project: POCT08 NOTE: The ISO standard term is “preexamination.”
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preanalytical variables events or circumstances that can alter the concentrations of analytes in a blood/urine specimen before the actual measurement Project: C31, C48 NOTE: These can include patient preparation, subject status, specimen collection technique, specimen storage and transportation, and specimen handling.
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preanalytical/preexamination processes processes that start, in chronological order, from the clinician's request and include the examination request, preparation and identification of the patient, collection of the primary sample(s), and transportation to and within the laboratory, ending when the examination begins (ISO 15189) Project: PRE05, POCT10
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preauthorization the process to seek approval before services are rendered Project: QMS22
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precaution statement that alerts the user to special care or procedures necessary for safe and effective use of the device (modified from ISO 18113-1) Project: ISO CD 18112-1
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precaution statement that alerts users to special care or activities necessary for safe and effective use of an IVD medical device or to avoid damage to the IVD medical device that could occur as a result of use, including misuse (ISO 18113-1)
Project: ISO 18113-1, ISO 18113-2, ISO 18113-3 NOTE 1: The distinction between warnings and precautions is a matter of degree, considering the likelihood and seriousness of the hazard. See the definition of warning (ISO 18113-1); NOTE 2: Adapted from US Food and Drug Administration, Guidance on Medical Device Patient Labelling; Final Guidance for Industry and FDA, 19 April 2001 (ISO 18113-1).
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precautionary statement phrase that describes recommended measure to be taken to minimize or prevent adverse effects resulting from exposure to a hazardous chemical or improper storage or handling of a hazardous chemical (see A Guide to the Globally Harmonized System of Classification and Labelling of Chemicals [GHS]) Project: GP17
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precentrifugation phase the time period after specimen collection and before specimen centrifugation
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preceptor teacher, tutor Project: QMS16
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precision (of measurement) closeness of agreement between indications or measured quantity values obtained by replicate measurements on the same or similar objects under specified conditions (JCGM 200:2012) Alternate Term: measurement precision Project: ISO IEC Guide 99, GP16, C34, C43, M51, H26, NBS04, MM06, H59, I/LA28, H02, EP23, MM19, NBS05, EP24, C51, EP17, C56, EP27, MM14, EP09, EP26, C40, I/LA26, MM22, MM09, EP06, EP05, EP15, C57, MM03, POCT06, M52, MM21, H48, POCT17, C64, EP21, QMS24, I/LA20, C24, EP34, EP07, C63, MM17, C49, M24, EP30, QMS23, MM24, EP39, H62, EP12, EP25, NBS10, MM26, M67 NOTE 1: Measurement precision is usually expressed numerically by measures of imprecision, such as standard deviation, variance, or coefficient of variation under the specified conditions of measurement (JCGM 200:2012); NOTE 2: The “specified conditions” can be, for example, repeatability conditions of measurement (within the same run), intermediate precision conditions of measurement, or reproducibility conditions of measurement (see ISO 5725-1:1994) (modified from JCGM 200:2012); NOTE 3: Measurement precision is used to define measurement repeatability, intermediate measurement precision, and measurement reproducibility (JCGM 200:2012); NOTE 4: Sometimes “measurement precision” is erroneously used to mean “measurement accuracy” (JCGM 200:2012); NOTE 5: The “specified conditions” can range from repeatability to reproducibility conditions of measurement (see ISO 5725-3); NOTE 6: “Precision of measurement” is a qualitative concept (ISO 15195); NOTE 7: The degree of precision is usually expressed numerically by statistical measures of imprecision of measurement such as “standard deviation” and “coefficient of variation” that are inversely related to precision (ISO 15195); NOTE 8: Precision is not typically represented as a numerical value but is expressed quantitatively in terms of “imprecision,” or the standard deviation or the coefficient of variation of the results in a set of replicate measurements; NOTE 9: See reproducibility and reproducibility condition; NOTE 10: For example, how close the results of a particular run are to each other; NOTE 11: Also called “imprecision”; NOTE 12: The closeness of agreement between independent test results from the same sample obtained under prescribed (stipulated) conditions (modified from ISO 5725-1); NOTE 13: Precision has no numerical value but is expressed in terms of imprecision – the standard deviation or the coefficient of variation of the results in a set of replicate measurements; NOTE 14: Repeatability (intra-assay precision) refers to agreement within an individual assay run. Within-laboratory or total precision (interassay precision) refers to results obtained from different sets of assays; NOTE 15: Precision depends only on the distribution of random errors and does not relate to the true value or the specified value (ISO 5725-1); NOTE 16: The measure of precision usually is expressed in terms of imprecision and computed as a standard deviation of the test results. Less precision is reflected by a larger standard deviation (ISO 5725-1); NOTE 17: Precision is closely related to “reproducibility” and “repeatability,” although each of these have specific technical meanings beyond the scope of QMS23; NOTE 18: Sometimes (for low value samples) precision is described by 2.5th and 97.5th percentiles.
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precision 1) (of measurement) closeness of agreement between independent test results obtained under stipulated conditions (ISO 5725-1); 2) the closeness of agreement between independent test results obtained under prescribed conditions (ISO Guide 30); 3) closeness of agreement between a series of measurements, under specified conditions, of a substance or biological product Project: ISO 15197, ISO CD 17593, ISO 15196 (June 2001), EP10, H26, H44, ISO 15198, I/LA23, C48, M33, H54, HS02, MM10, MM12, H56, GP40, H20, H58, POCT05, I/LA21, H57, POCT09, GP34, I/LA34, POCT04, EP31 NOTE 1: Precision depends only on the distribution of random errors and does not relate to the true value or the specified value (ISO 5725-1); NOTE 2: The measure of precision usually is expressed in terms of imprecision and computed as a standard deviation of the test results. Less precision is reflected by a larger standard deviation (ISO 5725-1); NOTE 3: “Independent test results” means results obtained in a manner not influenced by any previous result on the same or similar test object. Quantitative measures of precision depend critically on the stipulated conditions. Repeatability and reproducibility conditions are particular sets of extreme stipulated conditions (ISO 5725-1); NOTE 4: “Precision of measurement” is a qualitative concept (ISO 15195); NOTE 5: The degree of precision is usually expressed numerically by statistical measures of imprecision of measurement such as “standard deviation” and “coefficient of variation” that are inversely related to precision (ISO 15195); NOTE 6: “Precision” of a given measurement procedure is usually subdivided according to specific conditions into “repeatability” and “reproducibility”; “repeatability” relates to essentially unchanged conditions and is often termed “within-series precision” or “within-run precision.” “Intermediate precision” refers to conditions where there is variation in one or more of the factors time, calibration, operator, and equipment—usually within a laboratory. “Reproducibility” relates to change in conditions, ie, different laboratories, operators, and measuring systems (including different calibrations and reagent batches) and is often termed “interlaboratory precision” (modified from ISO 15195); NOTE 7: The degree of precision is usually expressed numerically by statistical measures of imprecision of measurements such as “standard deviation” and “coefficient of variation” that are inversely related to precision; quantitative measures of precision depend on the stipulated conditions (ISO 15197, ISO 15198, ISO CD 17593); NOTE 8: Precision of a given measurement procedure is subdivided according to the specified precision conditions. Particular sets of extreme conditions are termed “repeatability” and “reproducibility” (ISO 15197, ISO 15198, ISO CD 17593); NOTE 9: Precision of measurement cannot be given a numerical value in terms of the measurand, only descriptions such as ‘sufficient’ or ‘insufficient’ for a stated purpose (ISO 17511); NOTE 10: The degree of precision is usually expressed numerically by the statistical measures of imprecision of measurements, such as standard deviation and coefficient of variation, that are inversely related to precision (ISO 17511); NOTE 11: “Precision” of a given measurement procedure is subdivided according to the specified precision conditions. “Repeatability” relates to essentially unchanged conditions and is often termed “within-serial” or “within-run precision.” “Reproducibility” relates to changes in conditions, eg, time, different laboratories, operators, and measuring systems (including different calibrations and reagent batches) (ISO 17511); NOTE 12: Particular sets of extreme conditions are termed repeatability and reproducibility (ISO/DIS 15197); NOTE 13: Precision has no numerical value but is expressed in terms of imprecision—the standard deviation or the coefficient of variation of the results in a set of replicate measurements; NOTE 14: For example, how close the results of a particular run are to each other (AST04); NOTE 15: Precision can be expressed as good, medium, or bad and is expressed quantitatively in terms of imprecision - the standard deviation or the coefficient of variation of the results in a set of replicate measurements; NOTE 16: Intra-assay precision refers to agreement within an individual assay run. Interassay precision refers to results obtained from different sets of assays; NOTE 17: Precision is not typically represented as a numerical value but is expressed quantitatively in terms of imprecision, paired absolute relative difference, or the coefficient of variation of the results in a set of replicate measurements.
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precision the closeness of agreement between independent test results from the same sample obtained under prescribed (stipulated) conditions (modified from ISO 5725-1) Project: GP34, POCT10, POCT14 NOTE: Precision is not typically represented as a numerical value but is expressed quantitatively in terms of imprecision—the standard deviation or the coefficient of variation of the results in a set of replicate measurements.
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precision (of measurement) closeness of agreement between independent results of measurements obtained under stipulated conditions (ISO 17511) Project: ISO 15195, ISO 17511, ISO 15197, ISO 15198, C45, I/LA24, C48, I/LA02, ISO 17593, MM16, VET03, C52, I/LA21, C50, EP28 NOTE 1: “Precision of measurement” is a qualitative concept; NOTE 2: The degree of precision is usually expressed numerically by statistical measures of imprecision of measurements such as “standard deviation” and “coefficient of variation” that are inversely related to precision. Quantitative measures of precision depend on the stipulated conditions; NOTE 3: Precision of a given measurement procedure is subdivided according to the specified precision conditions. Particular sets of extreme conditions are termed “repeatability” and “reproducibility”; NOTE 4: “Precision” of a given measurement procedure is subdivided according to the specified precision conditions; “Repeatability” relates to essentially unchanged conditions and is often termed “within-series precision” or “within-run precision.” “Intermediate precision” refers to conditions where there is variation in one or more of the factors time, calibration, operator, and equipment - usually within a laboratory. “Reproducibility” relates to change in conditions, ie, different laboratories, operators, and measuring systems (including different calibrations and reagent batches) and is often termed “interlaboratory precision”; NOTE 5: The degree of precision is usually expressed numerically by statistical measures of imprecision of measurements such as “standard deviation” and “coefficient of variation” that are inversely related to precision; Quantitative measures of precision depend on the stipulated conditions; NOTE 6: Precision of a given measurement procedure is subdivided according to the specified precision conditions. Particular sets of extreme conditions are termed “repeatability” and “reproducibility”; NOTE 7: Precision of measurement cannot be given a numerical value in terms of the measurand, only descriptions such as ‘sufficient’ or ‘insufficient’ for a stated purpose; NOTE 8: The degree of precision is usually expressed numerically by the statistical measures of imprecision of measurements, such as standard deviation and coefficient of variation, that are inversely related to precision; NOTE 9: “Precision” of a given measurement procedure is subdivided according to the specified precision conditions. “Repeatability” relates to essentially unchanged conditions and is often termed “within-serial” or “within-run precision.” “Reproducibility” relates to changes in conditions, eg, time, different laboratories, operators, and measuring systems (including different calibrations and reagent batches); NOTE 10: Precision is not typically represented as a numerical value but is expressed quantitatively in terms of imprecision - the standard deviation or the coefficient of variation of the results in a set of replicate measurements.
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precision the degree to which repeated measurements or calculations show the same or similar results Project: POCT08, POCT15 NOTE: Precision is closely related to “reproducibility” and “repeatability,” although each of these terms has a specific technical meaning beyond the scope of POCT08 and POCT15.
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precision (of measurement) closeness of agreement between independent test results obtained under stipulated conditions (ISO 5725-1) Project: C58, MM20, H60, VET04, MM23, POCT13, POCT16 NOTE 1: Precision is not typically represented as a numerical value but is expressed quantitatively in terms of imprecision: the standard deviation or the coefficient of variation of the results in a set of replicate measurements; NOTE 2: For example, how close the results of a particular run are to each other.
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precision (of measurement) closeness of agreement between independent test/measurement results obtained under stipulated conditions (modified from ISO 17511) Project: C62 NOTE: Precision is not typically represented as a numerical value but is expressed quantitatively in terms of imprecision—the standard deviation or the coefficient of variation of the results in a set of replicate measurements.
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precision agreement between replicate measurements Project: I/LA34 NOTE: Intra-assay precision refers to agreement within an individual assay run. Interassay precision refers to results obtained from different sets of assays.
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precision (of measurement) 1) (measurement) closeness of agreement between indications or measured quantity values obtained by replicate measurements on the same or similar objects under specified conditions (JCGM 200:2012); 2) the closeness of agreement between independent test results obtained under stipulated conditions (ISO 5725-1) Project: MM01 NOTE: Precision is not typically represented as a numerical value but is expressed quantitatively in terms of imprecision—the standard deviation or the coefficient of variation of the results in a set of replicate measurements.
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precision (of measurement) the closeness of agreement between independent measurement procedure results obtained under stipulated conditions (modified from ISO 5725-1) Project: EP33 NOTE: Precision is not typically represented as a numerical value but is expressed quantitatively in terms of imprecision—the standard deviation or the coefficient of variation of the results in a set of replicate measurements.
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precision closeness of agreement between replicate test/measurement results obtained under stipulated conditions (ISO 17511) Project: EP19 NOTE: Precision is not typically represented as a numerical value but is expressed quantitatively in terms of imprecision—the standard deviation or the coefficient of variation of the results in a set of replicate measurements.
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precision (of measurement) closeness of agreement between indications or measured quantity values obtained by replicate measurements on the same or similar objects under specified conditions (JCGM 200:2012) Project: C52 NOTE: Measurement precision is usually expressed numerically by measures of imprecision, such as standard deviation, variance, or coefficient of variation under the specified conditions of measurement (JCGM 200:2012).
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precision medicine a medical practice that considers the germline genetics and the genetic changes in a tumor (and sometimes environment and lifestyle elements) to select the best treatment for an individual patient Alternate Term: personalized medicine Project: MM26 NOTE 1: In cancer (next-generation sequencing) testing, diagnostic, predictive, and prognostic biomarker results are considered to provide an integrated interpretative comment; NOTE 2: Alternative term is personalized medicine.
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precision profile the precision of an assay across the analyte concentration range of interest Project: I/LA34, I/LA20 NOTE: A precision profile is constructed by determining the standard deviation (or coefficient of variation) of replicate measurements (within assays, between assays, or between specimen dilutions within an assay) spanning the entire analyte concentration range, albeit without the exact knowledge of the true analyte concentration that is contained in the serum specimens. When the coefficient of variation of the dose (y-axis) is graphed against the dose (x-axis), a precision profile plot is generated. The precision profile is also referred to as the “imprecision profile” by some investigators.
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precision profile graphical depiction of the precision of an assay across a measurand concentration interval of interest Project: EP17 NOTE: A precision profile is constructed by determining the standard deviation (or coefficient of variation [CV]) of replicate measurements (repeatability, within-laboratory precision, or reproducibility) spanning an analyte concentration interval, albeit without the exact knowledge of the true analyte concentration that is contained in the specimens. When the CVconcentration (y-axis) is graphed against the mean values of replicate measurements (x-axis), a precision profile plot is generated. The precision profile is also referred to as the “imprecision profile” by some investigators.
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preclinical evaluation a preliminary evaluation to determine if the new assay’s analytical performance characteristics meet the desired design goals Project: I/LA21 NOTE: It serves as a determinant for proceeding to the clinical evaluation.
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precursor ion ion that reacts to form particular product ions. The reaction can be unimolecular dissociation ion/molecule reaction, isomerization, or change in charge state (IUPAC 2006) Project: C43 NOTE: Formerly known as parent ion.
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precursor ion an ion that can react to form specific product ions or that undergoes specified neutral loss Project: C64
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precursor ion scan a data acquisition mode for tandem mass spectrometry in which only those precursor ions that produce a particular fragment (product ion) are detected, resulting in a spectrum of precursor ions in which a product ion fragment has the same mass Project: NBS04, NBS09
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precursor lesions precancerous changes in the cervical/vaginal epithelium Project: GP15
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predicate device an assay or device for the in vitro measurement of an allergen-specific IgE antibody that has been cleared for marketing by the applicable government regulation or that was in commercial distribution before 1976 NOTE: The performance of a new assay or device can be measured and reported in terms of increased or decreased analytical sensitivity and analytical specificity, and limitations for use in direct comparison with a predicate assay.
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predictive biomarker biomarker that indicates whether the patient is a good candidate for a specific drug or regimen and identifies patients who are likely or unlikely to benefit from a specific treatment Project: MM23
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predictive biomarker a test result that measures the likelihood of a response or lack of a response to a specific therapy Project: MM26
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predictive marker biomarker that correlates with the response to a specific therapy Project: I/LA28 NOTE 1: Other outcomes that can be correlated are toxicity or dose; NOTE 2: A predictive biomarker guides therapy by functioning as a decision point in means of treatment. For example, breast cancers that express the estrogen receptor tend to respond to hormonal therapies such as tamoxifen.
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predictive value of a negative test 1) the percentage of negative test results that are true negatives when the test is applied to a population containing both healthy and diseased subjects; 2) the probability that a negative test result represents health Project: H26 NOTE: In predictive value theory, negative predictive value is mathematically defined as the proportion of test results that are true negatives, divided by the sum of true negatives and false negatives.
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predictive value of a negative test result (predictive value negative) the probability that a subject with a negative test result actually does not have the disease Alternate Term: predictive value negative Project: GP10 NOTE: This is a posteriori (or post-test) probability.
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predictive value of a positive test 1) the percentage of positive test results that are true positives when the test is applied to a population containing both healthy and diseased subjects; 2) the probability that a positive test result represents disease Project: H26 NOTE: In predictive value theory, positive predictive value is mathematically defined as the proportion of test results that are true positives, divided by the sum of true positives and false positives.
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predictive value of a positive test result (predictive value positive) the probability that a subject with a positive test result actually has the disease Alternate Term: predictive value positive NOTE: This is a posteriori (or post-test) probability.
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predisposition a gene variant that increases an individual’s susceptibility to a certain disease or disorder Project: MM19 NOTE: When such a variant is inherited, development of symptoms is more likely, but not certain.
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predisposition biomarker biomarker that confers an increased risk over the general population for developing a disease Project: MM23 NOTE: In cancer, increased risk is frequently attributed to a heritable, germline variant and is associated with earlier age of tumor onset, bilateral or multifocal tumors, or multiple relatives/generations of affected individuals.
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preevacuation the creation of a vacuum (in a collection tube), induced by either the manufacturer or by the user immediately before a liquid specimen is taken
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preevacuation the creation of a vacuum, induced during the manufacture of the tube or by the user immediately before use Project: PRE02
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preexamination (preanalytical phase) processes that start, in chronological order, from the clinician’s request and include the examination request, preparation and identification of the patient, collection of the primary specimen(s), and transportation to and within the laboratory and that end when the examination begins (ISO 15189) Project: EP23
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preexamination processes that start, in chronological order, from the clinician’s request and include the examination request, preparation and identification of the patient, collection of the primary sample(s), and transportation to and within the laboratory, and end when the analytical examination begins (ISO 15189) Project: PRE01, GP33
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preexamination processes processes that include, in chronological order, the request for examination, preparation and identification of the patient, collection of the specimen, transportation to and within the laboratory, and preparation of the specimen for examination, and end when the examination begins (modified from ISO 15189) Project: QMS06, QMS25, GP48, GP23, QMS22, QMS01 Source: Quality Glossary NOTE: For pathologists and cytotechnologists, preexamination activities extend from the time the tissue is removed or collected to the point where the slides are prepared and ready for diagnostic interpretation.
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preexamination processes processes starting, in chronological order, from the request for examination and including the examination requisition, preparation of the patient, collection of the primary sample, and transportation to or within the laboratory, and ending when the analytical examination procedure begins (modified from ISO 15189) Alternate Term: preanalytical phase Project: GP26
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preexamination processes See preanalytical Project: POCT08
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preintervention all processes in sequential order from test request and patient assessment to the therapeutic intervention Project: QMS07
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preliminary evaluation a phase in the Implementation Stage of the Test Life Phases Model; an initial determination of a new test method’s suitability, designed to quickly identify major flaws in the test method performance that would make it unsuited for meeting the end user’s needs Project: EP19
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premarket notification 510 (k) a written request from a commercial company to the FDA to obtain clearance to market a Class I or II product by establishing substantial equivalence to another legally marketed device
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premutation in triplet repeat disorders such as fragile X syndrome, a moderate expansion of the number of trinucleotide repeats that has no phenotypic effect, but has increased risk of undergoing full expansion during meiosis and causing full expression of the disorder in the offspring
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preparedness the knowledge and capacities developed by governments, professional response and recovery organizations, communities, and individuals to effectively anticipate, respond to, and recover from, the effects of likely, imminent, or current hazard events or conditions Project: POCT16
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preparedness planning and training efforts that integrate assets (people and necessary resources) to produce a coordinated and competent response during an emergency Project: GP36 EXAMPLE: Planning and then training personnel to use evacuation sleds to accomplish vertical patient evacuation in a hospital.
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preprocedure all processes in sequential order from procedure authorization, patient assessment, patient education, and equipment preparation
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prereduced anaerobically sterilized describes medium whose oxygen has been removed before heat sterilizing Project: M56 NOTE: This action prevents the reaction of reducing agents present in the medium with oxygen, which would lead to the formation of products that are harmful to, or would limit the growth of, anaerobes in that medium.
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preservative a substance used to prevent or reduce chemical or biological changes in the urine after collection Project: PRE05
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preservice all processes in sequential order from patient assessment, including physician medication ordering, care unit order processing, and transmission of the order to the pharmacist NOTE: This portion of the path of workflow ends when the pharmacist receives the physician’s order.
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presumptive positive result of a multitest algorithm indicating a high probability of infection Project: M53
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preterm born before 37 completed weeks (259 days) of gestation Alternate Term: premature Project: NBS03, NBS10
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pretest all processes in sequential order from test request and patient assessment to the pulmonary diagnostic test Project: QMS07
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pretest probability the a priori probability of a particular clinical state before results of a diagnostic test are known Project: H59 NOTE 1: This probability may be obtained by estimates of the prevalence of a disease in a population or by a clinical estimate of the probability of a disease existing in a given patient. See also Posterior probability. NOTE 2: An evaluation of clinical features (history, signs, and symptoms) that collectively assist in predicting the outcome of a test or procedure. For D-dimer, concentrations are described as low, intermediate or moderate (unlikely), and high (likely). Intermediate and moderate are used interchangeably and in this document, the term intermediate is used for consistency.
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prevalence the frequency of a condition of interest expressed as a percentage of the total number of individuals (those with the condition plus those without the condition of interest) in the population under study Project: H59, MM09, MM17 NOTE: An estimate of prevalence is calculated as 100 • (true positives + false negatives) / (true positives + false positives + false negatives + true negatives).
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prevalence the extent of occurrence expressed as a fraction of the numbers affected by the disease or condition compared to the total number of members in the specified group Project: I/LA23, GP45 NOTE 1: When used without qualification, the term usually refers to the situation at a specified point in time (point prevalence); NOTE 2: This is a number, not a rate.
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prevalence total number of cases of a disease in a population Project: M53 NOTE 1: When used without qualification, the term usually refers to the situation at a specified point in time (point prevalence); NOTE 2: This is a number, not a rate.
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prevalence the probability of a particular clinical state in a specified population or subpopulation at a given point in time Project: EP24 NOTE 1: One can expect the prevalence to change, depending upon the population under study; NOTE 2: Prevalence is a frequency, not a rate.
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prevalence rate the extent of occurrence expressed as a fraction of the numbers affected by the disease or condition compared to the total number of members in the specified group
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prevention the administration of an antimicrobial agent to an individual animal to mitigate the risk for acquiring disease or infection that is anticipated based on history, clinical judgment, and/or epidemiological knowledge and for which no etiological agent has yet been confirmed by culture or other detection method(s) Alternate Term: prophylaxis Project: VET03, VET01, VET09 NOTE 1: Generally used in a herd or flock situation and not an individual animal; NOTE 2: Generally used in a fish population and not an individual fish; NOTE 3: On a population basis, the administration of an antimicrobial agent to a group of animals, none of which have evidence of disease or infection, when transmission of existing undiagnosed infections, or the introduction of pathogens, is anticipated based on history, clinical judgment, and/or epidemiological knowledge; NOTE 4: Therapeutic use of antimicrobial drugs includes treatment, control (also known as metaphylaxis), and prevention (also known as prophylaxis); NOTE 5: See breakpoint, control//metaphylaxis, and treatment.
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prevention administration of an antimicrobial agent to exposed healthy animals considered to be at risk, but before onset of disease, and for which no etiological agent has yet been confirmed by culture or other detection method(s) Alternate Term: prophylaxis Project: VET06 NOTE: Generally, the usage is in a herd or flock situation and not an individual animal.
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prevention costs costs of all activities specifically designed to prevent poor quality in products or services Project: QMS20
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preventive action action to eliminate the cause of a potential nonconformity or other potential undesirable situation (ISO 9000) Project: GP26, QMS11, QMS06, QMS13, EP18, QMS01 Source: Quality Glossary NOTE 1: There can be more than one cause for a potential nonconformity (ISO 9000); NOTE 2: Preventive action is taken to prevent occurrence whereas corrective action is taken to reduce or eliminate recurrence (modified from ISO 9000).
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preventive maintenance scheduled periodic work on a piece of equipment that is not a result of malfunction or failure and is intended to avert such failure Project: GP26, GP23, QMS23
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primary antibody an antibody generated against an antigenic target Project: ILA29
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primary antibody an antibody that binds directly to the specific protein of interest Project: H42, H43
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primary biomarker analyte or ratio of analytes that is typically out of range (high or low, present or absent, depending on the marker) in a particular disease, disease form, or phenotype Alternate Term: primary marker Project: NBS13, NBS09 Source: Newborn Screening Glossary NOTE 1: In newborn screening, this analyte and/or ratio of analytes is typically assessed first in all newborns to determine whether additional testing or secondary biomarker analysis is needed; NOTE 2: See biomarker and secondary biomarker.
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primary certified reference material reference material having the highest metrological qualities and whose value is determined by means of a primary reference measurement procedure, directly to the International System of Units or indirectly by determining the impurities of the material by appropriate analytical methods Project: EP32 NOTE: A primary certified reference material shall have its value assigned either directly by a primary reference measurement procedure or by a fit-for-purpose measurement procedure for identity and/or purity assessment of pure substances (eg, quantitative nuclear magnetic resonance, mass balance, gene sequencing).
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primary congenital hypothyroidism thyroid hormone deficiency that is present at birth and that is caused by a problem with thyroid gland development (ie, dysgenesis) or with thyroid hormone biosynthesis (ie, dyshormonogenesis) Project: NBS10 Source: Newborn Screening Glossary
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primary container packaging that protects the contents from contamination and/or other effects of the external environment Alternate Term: primary container Project: ISO CD 18112-1 EXAMPLES Sealed vial, ampoule or bottle, a foiled pouch, or a sealed plastic bag containing culture media, microtitration plates or coated tubes.NOTE: A vessel, including its closure, that contains the specimen.
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primary container the innermost packaging containing a diagnostic specimen or infectious substance that is composed of glass, metal, or plastic and must be leakproof and positively sealed if it contains an infectious substance Alternate Term: primary receptacle Project: M29
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primary health care provider health care professional who provides routine health care and coordinates and collaborates with specialty care providers Project: NBS02 NOTE 1: In some jurisdictions, the terms “primary care physician” or “medical home” might be used; NOTE 2: See health care provider and specialty care provider.
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primary markers analytes that are consistently abnormal (high or low, depending on the marker) in a particular condition Project: NBS04
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primary measurement standard See primary standard
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primary ovarian insufficiency loss of function of the ovaries before age 40
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primary patient identifiers unique identifiers that often remain consistent to the patient throughout all or most of his or her lifetime. (eg. patient’s full name, date of birth, sex) Project: PRE01
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primary receptacle See primary container Alternate Term: primary container Project: M29
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primary reference laboratory (PRL) a laboratory in the NGSP laboratory network using a DCM; NOTE 1: There is a Central Primary Reference Laboratory (CPRL) and several backup laboratories (PRLs); NOTE 2: This type of laboratory is referred to as a “reference measurement laboratory” in ISO terminology Project: C44
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primary reference material reference material having the highest metrological qualities and whose value is determined by means of a primary reference measurement procedure Alternate Term: primary calibrator Project: ISO 17511, MM06, C40 NOTE 1: The concept “primary calibrator” is subordinate to “calibrator” and to “primary reference material”; NOTE 2: For reference materials, the value can be obtained by applying a primary reference measurement procedure.
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primary reference measurement procedure reference measurement procedure having the highest metrological qualities, whose operation can be completely described and understood, for which a complete uncertainty statement can be written down in terms of the International System of Units, and where results are, therefore, accepted without reference to a measurement standard of the quantity being measured Project: ISO 17511, EP32 NOTE 1: The Consultative Committee on Amount of Substance (CCQM) uses the term ‘primary method of measurement,’ but the term ‘primary reference measurement procedure’ in the present context is in conformity with VIM (see method of measurement with Note). The term ‘definitive method’ was omitted in VIM, but is sometimes used for a thoroughly investigated and evaluated reference measurement procedure (see reference measurement procedure) of high accuracy; NOTE 2: The abbreviated term ‘primary reference procedure’ cannot cover a procedure for a nominal-scale property.
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primary reference measurement procedure reference measurement procedure used to obtain a measurement result without relation to a measurement standard for a quantity of the same kind (JCGM 200:2012) Alternate Term: primary reference procedure Project: JCGM 200:2012, C40 EXAMPLE: The volume of water delivered by a 50-mL pipette at 20°C is measured by weighing the water delivered by the pipette into a beaker, taking the mass of the beaker plus water minus the mass of the initially empty beaker, and correcting the mass difference for the actual water temperature using the volumic mass (mass density) (JCGM 200:2012); NOTE 1: The Consultative Committee for Amount of Substance – Metrology in Chemistry (CCQM) uses the term “primary method of measurement” for this concept (JCGM 200:2012); NOTE 2: Definitions of two subordinate concepts, which could be termed “direct primary reference measurement procedure” and “ratio primary reference measurement procedure,” are given by the CCQM (5th Meeting, 1999) (JCGM 200:2012); NOTE 3: Formerly, the term definitive method was used in C40; NOTE 4: May be referred to as “gold standard” method.
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primary reference medium coded lot of Mueller-Hinton agar selected by the CLSI Subcommittee on Culture Media Project: M6 NOTE 1: It is stored at a facility selected by the subcommittee and is tested at one-year intervals to determine stability; NOTE 2: Past experience with the first primary reference standard (lot 5) indicates that the dehydrated medium has excellent stability (about ten years) when stored in sealed glass jars at controlled room temperature; NOTE 3: The primary reference medium is provided to manufacturers of dehydrated Mueller-Hinton agar for evaluation of production lots. The primary reference medium is also distributed for stability testing and for the development of new primary and secondary reference media. The manufacturer of this lot is only known by the coding laboratory; NOTE 4: New reference media will be selected whenever appropriate; i.e., when the current supply nears depletion (<5000 g), or shows signs of deterioration or unsatisfactory performance.
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primary sample collection of one or more parts initially taken from a system and intended to provide information about the system, or to serve as a basis for a decision about the system (ISO 15193) Alternate Term: specimen Project: ISO 15193, H48 NOTE 1: In some cases, the information provided also applies to a larger system or a set of systems, of which the sampled system is an element (ISO 15193); NOTE 2: In some countries, the term “specimen” is used instead of primary sample (or a subsample of it), which is the sample prepared for sending to, or as received by, the laboratory, and which is intended for examination (ISO 15189).
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primary sample collection device apparatus specifically intended by an IVD manufacturer to obtain, contain, and preserve a body fluid or tissue for in vitro diagnostic examination (ISO 18113-1)
Alternate Term: specimen collection device Project: ISO 18113-1 NOTE 1: Includes devices intended to store a primary sample prior to examination (ISO 18113-1); NOTE 2: Includes both vacuum and nonvacuum primary sample collection devices (ISO 18113-1); NOTE 3: Adapted from Directive 98/79/EC of the European Parliament and the Council of 27 October 1998 on in vitro diagnostic medical devices, Official Journal of the European Union L331, 7 December 1998, Article 1, 2(b) (ISO 18113-1).
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primary specimen the specimen used for the original characterization and documentation of the measurement procedure performance characteristics Project: EP35 NOTE: All other specimen types are candidate specimen types for the purposes of CLSI EP35. The primary specimen type cannot be redefined for subsequent evaluations.
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primary standard measurement standard established using a primary reference measurement procedure, or created as an artifact, chosen by convention (JCGM 200:2012) Alternate Term: primary measurement standard Project: ISO IEC Guide 99, H58, POCT05, H26, MM06, I/LA28, H57, MM12, ISO 17511, ISO 15194, C40 EXAMPLE 1: Primary measurement standard of amount-of-substance concentration prepared by dissolving a known amount of substance of a chemicalcomponent to a known volume of solution (JCGM 200:2012); EXAMPLE 2: Primary measurement standard for pressure based on separate measurements of force and area (JCGM 200:2012); EXAMPLE 3: Primary measurement standard for isotope amount-of-substance ratio measurements, prepared by mixing known amount-of-substances of specified isotopes (JCGM 200:2012); EXAMPLE 4: Triple-point-of-water cell as a primary measurement standard of thermodynamic temperature (JCGM 200:2012); EXAMPLE 5: The international prototype of the kilogram as an artifact, chosen by convention (JCGM 200:2012); NOTE 1: A reference material that is of fixed and known chemical composition and capable of being prepared in essentially pure form; NOTE 2: Alternatively, any certified reference material that is generally accepted or officially recognized as the unique standard for the assay, regardless of its level of purity of analyte content; NOTE 3: The concept of “primary measurement standard” is equally valid for base quantities and derived quantities; NOTE 4: For reference materials, the value can be obtained by applying a primary reference measurement procedure (ISO 17511).
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primary standard measurement standard whose quantity value and measurement uncertainty are established using a primary measurement procedure (ISO 15194) Alternate Term: primary measurement standard Project: ISO 15194 EXAMPLE: Primary measurement standard of amount-of-substance concentration prepared by dissolving a known amount of substance of a chemical component to a known volume of solution (ISO 15194); NOTE 1: The concept of "primary measurement standard" is equally valid for base quantities and derived quantities (ISO 15194); NOTE 2: Further explanation of the role of primary measurement standards within a calibration hierarchy can be found in ISO 17511 and ISO 18153 (ISO 15194).
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primary standard (calibrator) a reference material that is of fixed and known chemical composition and capable of being prepared in essentially pure form Project: H15 NOTE: Alternatively, any certified reference material that is generally accepted or officially recognized as the unique standard for the assay, regardless of its level of purity of analyte content.
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primary target disease (for newborn screening) a disease, disease form, or phenotype that the newborn screening test is designed to detect Project: NBS06, NBS09, NBS07, NBS13 Source: Newborn Screening Glossary NOTE 1: Primary target diseases typically meet the following minimum criteria: the disease can be identified by newborn screening of most affected newborns before clinical presentation; a suitable screening test is available; and the benefits of early detection and intervention, as well as efficacious treatments for the disease, have been documented; NOTE 2: Target diseases can also be referred to as “target conditions” or “target disorders”; NOTE 3: See secondary target disease.
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primer (QRT-PCR) a single-stranded nucleic acid that can initiate replication of a template Project: MM16 NOTE 1: More specifically, a single-stranded nucleic acid capable of hybridizing to a template single-stranded nucleic acid in such a way as to leave part of the template to the 3´ end of the primer single-stranded. DNA polymerase can then synthesize a new strand starting from the 3´ end of the primer and adding nucleotides to the growing strand by base complementarity to the template; NOTE 2: Primers used for quantitative reverse transcriptase real-time polymerase chain reaction are generally designed by specialized software taking into account a number of parameters (melting temperature, primers-dimers formation, guanine-cytosine percentages) to optimize the polymerase chain reaction.
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primer an oligonucleotide, which when hybridized to a complementary strand of target DNA and in the presence of DNA polymerase and nucleoside triphosphates, can act to initiate DNA synthesis from its 3′-hydroxyl (-OH) end Project: MM03, MM18, MM17, MM05 NOTE: DNA synthesis cannot initiate de novo, and these conditions are the only conditions under which DNA synthesis can be initiated.
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primer an oligonucleotide usually of 18 to 25 bases that, when hybridized to a complementary strand of target DNA and in the presence of DNA polymerase and nucleoside triphosphates, can act to initiate DNA synthesis from its 3´-OH end Project: MM10, M55, MM22, MM24 NOTE: DNA synthesis cannot initiate de novo and these conditions are the only conditions under which DNA synthesis can be initiated.
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primer an oligonucleotide that hybridizes with one strand of a DNA or RNA template, providing a free 3′–OH end at which a polymerase starts the synthesis of a new, complementary strand Project: MM09
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primer an oligonucleotide usually of 18 to 25 bases which, when hybridized to a complementary strand of template DNA in the presence of DNA polymerase and nucleoside triphosphates, defines the site of initiation of DNA synthesis from its 3´-OH ends Project: NBS06 NOTE: Primers are essential for DNA amplification to occur and must be specific for the chosen amplicon.
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primer in a polymerase chain reaction, an oligonucleotide, which when hybridized to a complementary strand of target DNA and in the presence of DNA polymerase and nucleoside triphosphates, can act to initiate DNA synthesis from its 3′-OH end Project: MM19 NOTE: DNA synthesis cannot initiate de novo, and these conditions are the only conditions under which DNA synthesis can be initiated.
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primer an oligonucleotide that, when hybridized to a complementary strand of target DNA and in the presence of appropriate reagents and conditions, can act to initiate DNA synthesis Project: POCT15
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primer dimer a nonspecific product made during polymerase chain reaction amplification that incorporates the sequences of the forward and reverse primers and a few intervening nucleotides in a small polymerase chain reaction amplicon Project: MM17 NOTE: The amplification of primer dimer is very efficient and can compete with the amplification of the desired target and cause a loss of assay sensitivity.
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principal assigned value (PAV) a value that has been given to a material and is based on using the method considered most likely to be accurate when no definitive or reference method has been established, and is to be used as the accepted or desired value for an analyte
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principle of measurement scientific basis of a measurementEXAMPLESa) the thermoelectric effect applied to the measurement of temperature;b) the Josephson effect applied to the measurement of electric potential difference;c) the Doppler effect applied to the measurement of velocity;d) the Raman effect applied to the measurement of the wave number of molecular vibrations
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prions abnormally folded host membrane proteins associated with transmissible spongiform encephalopathies and demonstrate resistance to conventional disinfection and sterilization procedures Project: M29
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private key the secret component of a pair of cryptographic keys used for asymmetric cryptography (See public key) (RFC 2828) Project: AUTO09
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probability the letter P, followed by the abbreviation n.s. (not significant) or by the symbol < (less than) and a decimal notation such as 0.01, 0.05, is a statement of the probability that the difference observed could have occurred by chance, if the groups are really alike (ie, under the null hypothesis) Alternate Term: P value Project: GP45 NOTE 1: Investigators may arbitrarily set their own significance levels, but in most biomedical and epidemiological work, a study result whose probability value is less than 5% (P<0.05) or 1% (P<0.01) is considered sufficiently unlikely to have occurred by chance to justify the designation “statistically significant”; NOTE 2: See also statistical significance.
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probability refers to the likelihood of occurrence
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probability distribution a function giving the probability that a random variable takes any given value or belongs to a set of values (ISO 3534-1-1.3)
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probability distribution the relationship between the possible values of a random variable and their probabilities
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probability of target attainment in Monte Carlo simulations, the probability that at least a specific value of a pharmacodynamic index (eg, 30% fT>MIC; fAUC/MIC of 100) is achieved at a certain minimal inhibitory concentration Project: M23
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probable valid biomarker biomarker considered to have predictive value for clinical outcomes but that has not yet been fully accepted as a valid marker because of insufficient data (independent replication studies) or because the supporting data are inconclusive NOTE: Probable valid biomarkers are measured in analytical test systems with well-established performance characteristics.
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proband (of a performance evaluation study) an individual being part of a study in order to obtain specimen(s) with defined characteristics to be used for the performance evaluation study Project: prEN13612 (April 2000)
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proband the affected individual through whom a family with a genetic disorder is ascertained; also known as either the propositus or index case Project: MM19 NOTE: The proband may or may not be the consultand, who is the individual who is referred for genetic counseling.
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probe (microarray) defined piece of nucleic acid that is immobilized on the microarray substrate and is used to identify specific DNA or RNA molecules bearing the complementary sequence Project: MM16 NOTE: The production of cDNA arrays typically does not include separating the strands and only spotting a single strand of nucleic acid.
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probe (QRT-PCR) a single-stranded nucleic acid that binds to amplicon sequences between QRT-PCR primers with a fluorophore and enhances the specificity of sequence detection and quantification Project: MM16 NOTE: One example of this type of probe is in the 5´ nuclease reaction, where fluorescent markers with different excitation/emission profiles can be used on different probes to multiplex QRT-PCR for the simultaneous detection of target sequence and control sequence. The 5´ nuclease reaction signal is generated as free fluorescent molecules are released from the 5´ end of a probe where they had been quenched by a quencher group attached to the 3´ end of the probe.
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probe defined piece of single-stranded nucleic acid used to identify specific DNA or RNA molecules bearing the complementary sequence Project: MM01, MM10, MM12, M55, MM03, POCT15 NOTE 1: A probe can carry a label (radioactive or chemical) so that the probe can later be detected; NOTE 2: In one usage, the probe is the molecule (eg, complementary DNA, oligonucleotide) immobilized on the solid support to form the array. Alternatively, probe defines the labeled mixture in solution that hybridizes or reacts with target molecules attached to the support. The latter definition is the original definition of probe, whereas the former has come into usage more recently; NOTE 3: The probe often carries a label (radioisotopic or chemical), to facilitate detection of the probe recognizing its target.
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probe defined segment of single-stranded nucleic acid used to identify specific DNA or RNA molecules bearing the complementary sequence Project: MM22, MM24 NOTE 1: The probe often carries a label (radioisotopic, chemical, or fluorescent) to allow detection of the probe and/or facilitate detection of the probe recognizing its target; NOTE 2: In one usage, the probe is the molecule (eg, complementary DNA, oligonucleotide) immobilized on the solid support to form the array.
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probe a single-stranded oligonucleotide used to identify specific DNA or RNA molecules bearing the complementary sequence Project: NBS06 NOTE: A probe can carry a label (radioactive or chemical) so that the probe can later be detected.
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probe sensitivity a measurement of a FISH probe’s ability to detect its intended target (number of signals located over the intended target divided by the total number of intended targets) Project: MM07
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probe specificity a measurement of a FISH probe’s ability to detect only its intended target (number of signals located over the intended target divided by the total number of signals over all chromosomal targets) Project: MM07
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probit a mathematical transformation function for ratio or percentage values in cumulative normal distribution probability units Project: EP17 NOTE: “Probability units” = probits.
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probit regression regression analysis in which the response function Y can have only two responses (ie, detected or not detected) and the predictor variable X is the mean value of replicate measurements Project: EP17 NOTE: This technique is widely used to evaluate the limit of detection of molecular measurement procedures.
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procedure specified way to carry out an activity (modified from ISO 9000) Project: QMS06, QMS03, QMS02, QMS07, QMS21, I/LA33, QMS25, GP26, GP23, C57, QMS16, QMS21, QMS25, GP48, QMS01 Source: Quality Glossary NOTE 1: Procedures can be documented or not (ISO 9000); NOTE 2: When a procedure is documented, the term “written procedure” or “documented procedure” is frequently used. The document that contains a procedure can be called a “procedure document” (ISO 9000); NOTE 3: For a quality management system, a procedure is a set of instructions that describes the stepwise actions taken to complete activities identified in processes; NOTE 4: A series of tasks usually performed by one person according to instructions.
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procedure control a specimen that is drawn, prepared, and stained with the same protocol used for patient specimens Project: H42, H43, H52 NOTE 1: It is used; 1) for instrument setup and monitoring for setting test-specific instrument settings and establishing color compensation settings; and 2) as a control specimen for sample and data analysis; NOTE 2: Internal controls are acceptable procedural controls for cell-based assays and are considered superior to external controls by virtue of reporting on the exact assay conditions exposed to the assay target population of interest.
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procedure manual a document that contains the step-by-step methods and other information needed to carry out all pertinent laboratory tasks Project: POL1/2
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procedure manual a handbook that contains the methods, materials, and other information needed to perform a test Project: POCT04
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procedure manual a handbook that contains the measurement procedures, materials and other infromation needed to perform a test
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procedure tables free-standing tables used as part of laboratory casework systems NOTE: The tables can be adjustable height and on wheels or casters if desired.
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process set of interrelated or interacting activities that transforms inputs into outputs (modified from ISO 9000) Project: GP26, QMS02, POCT05, POCT05, GP23, QMS16, QMS06, QMS07, QMS08, I/LA33, QMS18, QMS21, QMS25, QMS03, QMS01, QMS29 Source: Quality Glossary NOTE 1: A process may be documented as a flow chart or table that describes operations in the laboratory’s path of workflow or activities within a quality system essential; NOTE 2: A process is a set of related tasks and activities that accomplishes a work goal; NOTE 3: A process is a naturally occurring or designed sequence of changes in time of properties or attributes of an object or a system. For example, G(t) is the process of glucose fluctuations over a specified period of time; NOTE 4: Whether the “intended result” of a process is called output, product, or service depends on the context of the reference (ISO 9000); NOTE 5: Inputs to a process are generally the outputs of other processes and outputs of a process are generally the inputs to other processes (ISO 9000).
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process in-laboratory activities to prepare a specimen for examination. Processing includes specific specimen handling activities such as centrifuging, pipetting, aliquotting, and preparing a protein-free filtrate Project: PRE04
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process audit an audit of the elements (ie, conditions and resources) supporting an activity or a process Project: QMS15 NOTE 1: A process audit examines the resources (eg, equipment, materials, people) applied to transform the inputs into outputs, the environment, the methods (ie, procedures, instructions) followed, and the measures collected to determine process performance; NOTE 2: A process audit checks the adequacy and effectiveness of the process controls established by procedures, work instructions, flow charts, and training and process specifications.
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process control a method of managing the process required to produce a result from a patient specimen and to handle/manipulate/transport the specimen, as applied to the CLSI standards, under the control or supervision of software that controls instruments/devices and automation hardware Project: AUTO01, AUTO02, AUTO03
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process control a method of managing the process required to produce a result
Project: H62
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process control mechanisms for maintaining the output of a specific process within desired parameters Project: QMS01 Source: Quality Glossary
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process improvement process management focused on reducing variation and improving process effectiveness and efficiency (ISO 3534-2) Project: GP26 NOTE: For the purposes of CLSI document GP22, the term "continual improvement" is used.
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process instruments in Automation, components of an automated laboratory comprising the automated devices that perform a multitude of pre- and postanalytical tasks, and perform nonanalytical tasks on specimens, containers, carriers, and similar processes Project: AUTO01, AUTO02
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process mapping graphical descriptions of processes that include detailed flow charts, workflow diagrams, and value stream maps Project: EP23 NOTE: A lean manufacturing technique used to analyze the flow of materials and information currently required to bring a product or service to a consumer.
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process validation establishing documented evidence that provides a high degree of assurance that a specific process will consistently produce a product meeting its predetermined specifications and quality characteristics Project: I/LA33 NOTE: The process shall be validated and approved according to established procedures.
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procollagen Type I C propeptide C-terminal extension of procollagen Type I NOTE: Also referred to as the C-terminal propeptides of procollagen Type I.
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procollagen Type I N propeptide N-terminal extension of procollagen Type I Project: C48 NOTE: Also referred to as the N-terminal propeptides of procollagen Type I.
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procurement refers to the overarching processes for obtaining products and services, including activities involved in establishing fundamental requirements, identifying sourcing activities (eg, market research), negotiating contracts, and evaluating suppliers Project: QMS21
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product output of an organization that can be produced without any transaction taking place between the organization and the customer (ISO 9000) Project: GP26, M52, QMS21 EXAMPLE: A medical device or system offered by a manufacturer to provide in vitro diagnostic device results; NOTE 1: There are four generic product categories, as follows :a) services (eg, transport: a health care organization processes produce services such as diagnostic testing or imaging, medications, respiratory or rehabilitation treatments, surgery, patient care); b) software (eg, computer program, dictionary; generally, health care organizations or services do not produce software); c) hardware (eg, engine mechanical parts: generally, health care organizations or services do not produce hardware); d) processed materials (eg, lubricant: generally, health care organizations or services do not produce processed materials) (modified from ISO 9000); NOTE 2: There are four generic product categories, as follows: a) services (eg, a laboratory produces services such as diagnostic examinations and consultation); b) software (eg, computer program, dictionary: generally, laboratories do not produce software); c) hardware (eg, engine mechanical parts: generally, laboratories do not produce hardware); d) processed materials (eg, blood products) (modified from ISO 9000); NOTE 3: A medical device or system offered by a manufacturer to provide in vitro diagnostic results; NOTE 4: The products discussed in this document are microbial identification and antimicrobial susceptibility testing systems; NOTE 5: See medical device.
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product calibrator calibrator intended for use with the manufacturer’s final product Project: ISO 17511, MM06
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product failure failure of a test system to meet the manufacturer’s specifications (including expected quality control results) when shipped, stored, and performed according to the manufacturer’s instructions Project: M50
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product insert informational material that comes with instruments, reagents, and other laboratory products that gives instructions for the use of the product and other information required of the manufacturer by the U.S. Food and Drug Administration, or other authoritative body Project: POL1/2
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product ion an ion formed as the product of a reaction involving a particular precursor ion. The reaction can be unimolecular dissociation to form fragment ions, an ion/molecule reaction, or simply involve a change in the number of charges (IUPAC 2006) Project: C43 NOTE: Formerly known as daughter ion.
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product ion an ion that is produced by reaction or fragmentation of a precursor ion Project: C64
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product or service audit an independent examination of the characteristics and attributes of a product or service against a specification or acceptance criterion Project: QMS15 NOTE: A service can include products that are documents (eg, report, contract, design).
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production use administration of an antimicrobial agent, usually as medicated feed over a period of time to growing animals, that results in improved physiological performance (eg, for increased rate of weight gain and improved feed efficiency), sometimes referred to as growth promotion, health maintenance, or nontherapeutic use Project: VET03, VET01
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professional continuous glucose monitoring a continuous glucose monitoring (CGM) system used by health care professionals for tracking or trending of glucose Project: POCT05 NOTE: A professional CGM system does not have to provide real-time glucose levels to the patient.
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professional development formal lectures, courses, seminars, webinars, or any other similar type of educational program designed to educate an individual and give him or her new skills or knowledge in preparation for advancement or a future position Project: QMS16 EXAMPLE: A person performing laboratory examinations in microbiology would seek continuing education to stay current in microbiology, whereas the same person would seek professional development to acquire new knowledge and skills to become an effective microbiology section manager.
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professional use use by personnel who have received special education and training with regard to procedures utilizing in vitro diagnostic medical devices and, when applicable, who are entitled to provide health services under the laws of the country (ISO/CD 18112-1) Project: ISO CD 18112-1
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professional use designation that an IVD medical device is intended for personnel who are qualified to perform IVD examinations through special education and training (ISO 18113-1)
Project: ISO 18113-1, ISO 18113-2, ISO 18113-3 NOTE: Adapted from EN 375:2001, definition 3.14 (ISO 18113-1).
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proficiency sample the material contained in a vial, on a slide, or other unit that contains material to be tested by proficiency testing program participants
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proficiency sample a specimen containing analytes of unknown concentration or identification that is sent to laboratories participating in testing programs in order to independently verify the laboratories’ technical competency. See also Challenge Project: POL1/2
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proficiency sample a sample containing measurands of undisclosed concentration or composition that is sent to laboratories participating in interlaboratory comparison programs in order to independently verify the laboratories’ technical competence Project: QMS24
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proficiency test materials manufacturers organizations that manufacture the materials used in quality and proficiency testing NOTE 1: They may be the contract manufacturer for a quality assessment organization; NOTE 2: Documents that state the type of material/specimen, and design and management of the programs are useful.
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proficiency test providers for the purposes of this document, organizations that administer and manage one or several proficiency test programs Alternate Term: organizations NOTE: This includes selection, distribution, receiving and analyzing results, reporting back to participants, and reporting to regulatory or certifying agencies when deemed.
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proficiency testing an external program in which samples are periodically sent to testing sites for analysis Alternate Term: external quality assessment Project: POCT04, POCT16 NOTE: Usually, the results are tabulated by the program and a participating site can compare its results with those of other sites that use a similar method.
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proficiency testing determination of laboratory testing performance by means of interlaboratory comparisons Alternate Term: quality assessment program; external quality assessment Project: C48, MM14, HS02, POCT08, EP19, MM19, MM22, EP31, MM24 NOTE 1: Commonly, a program periodically sends multiple specimens or samples to members of a group of laboratories for analysis and/or identification; the program then compares each laboratory’s results with those of other laboratories in the group and/or with an assigned value and reports the results to the participating laboratory and others; NOTE 2: Other forms of proficiency testing/external quality assessment include data interpretation/transformation exercises, intralaboratory comparisons, single-item testing (in which one item is sent to a number of laboratories sequentially and returned to the program at intervals), and one-off exercises (in which laboratories are provided with a test item on a single occasion); NOTE 3: The results are summarized, analyzed, and, with some tests, graded by the program and provided to the participating site, which can compare its results with those of other sites that use a similar method; NOTE 4: In some countries, external quality assessment/proficiency testing can use government-approved proficiency testing providers (http://wwwn.cdc.gov/mlp/pdf/EQA/eqa_list.pdf) (http://www.cms.hhs.gov/clia), which are different than interlaboratory comparisons. Also, and more formally, known as “external quality assessment”; NOTE 5: In the United States, proficiency testing is also a requirement for compliance with federal regulations for clinical laboratories.
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proficiency testing a program in which multiple samples are periodically sent to members of a group of laboratories for analysis and/or identification, in which each laboratory’s results are compared with those of other laboratories in the group and/or with an assigned value, and reported to the participating laboratory and others Alternate Term: external quality assessment Project: H26, C24, I/LA20 NOTE 1: Proficiency testing is an independent (nonmanufacturer sponsored) program in which challenge specimens (eg, serum) are sent to participating clinical laboratories to be evaluated in assays that measure a spectrum of analytes; NOTE 2: The purpose of proficiency testing is to evaluate the laboratory’s proficiency to measure a particular analyte. The results are returned to the sponsoring agency, which computes the performance of a given laboratory for a particular analyte using a particular method. Issues related to proficiency testing include computation of method performance using mean, standard deviation, and coefficient of variation measures to assess accuracy, and interlaboratory reproducibility of peer groups (that use the same and different assay methods); NOTE 3: Used to establish between-laboratory and between-instrument comparability that is, if possible, in agreement with a reference standard (when one exists). External quality assessment schemes may be regional, national, or international. External quality assessment is sometimes also referred to as proficiency testing, especially when the external agency is a regulatory agency; NOTE 4: Interlaboratory comparisons and other performance evaluations that may extend throughout all phases of the testing cycle, including interpretation of results; determination of individual and collective laboratory performance characteristics of examination procedures by means of interlaboratory comparison; NOTE 5: The primary objectives of proficiency testing/external quality assessment are educational and may be supported by additional elements.
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proficiency testing a program in which multiple specimens are periodically sent to members of a group of sites for analysis and/or identification, in which each site’s results are compared with those of other participants in the group and/or with an assigned value, and reported to the participating facilities and others Project: POCT10
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proficiency testing a program in which multiple samples are periodically sent to members of a group of laboratories for analysis or identification, in which each laboratory’s results are compared with those of other laboratories in the group or with an assigned value Alternate Term: external quality assessment Project: C52
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proficiency testing evaluation of participant performance against preestablished criteria by means of interlaboratory comparisons (ISO/IEC 17043) Project: GP26, QMS11, MM09, GP23, QMS24, MM17, QMS01 Source: Quality Glossary NOTE 1: For the purposes of ISO 17043, the term “proficiency testing” is taken in its widest sense and includes, but is not limited to: a) quantitative scheme – in which the objective is to quantify one or more measurands of the proficiency test item; b) qualitative scheme – in which the objective is to identify or describe one or more characteristics of the proficiency test item; c) sequential scheme – in which one or more proficiency test items are distributed sequentially for testing or measurement and returned to the proficiency testing provider at intervals; d) simultaneous scheme – in which proficiency test items are distributed for concurrent testing or measurement within a defined time period; e) single occasion exercise – in which proficiency test items are provided on a single occasion. It may be advantageous to pilot the change to evaluate its effectiveness before implementing a full-scale change; f) continuous scheme – in which proficiency test items are provided at regular intervals; g) sampling – in which samples are taken for subsequent analysis; and h) data transformation and interpretation – in which sets of data or other information are furnished and the information is processed to provide an interpretation (or other outcome); NOTE 2: Some providers of proficiency testing in the medical area use the term “external quality assessment” for their proficiency testing schemes, or for their broader programs, or both; NOTE 3: The requirements of ISO 17043 cover only those external quality assessment activities that meet the definition of proficiency testing (ISO 17043); NOTE 4: In some countries, the proficiency testing programs for medical laboratories are called “external quality assessment” programs (modified from ISO/IEC 17043); NOTE 5: Commonly, a program periodically sends multiple specimens or samples to members of a group of laboratories for analysis and/or identification; the program then compares each laboratory’s results with those of other laboratories in the group and/or with an assigned value and reports the results to the participating laboratory and others; NOTE 6: Other forms of proficiency testing include data transformation exercises, single-item testing (in which one item is sent to several laboratories sequentially and returned to the program at intervals), and one-off exercises (in which laboratories are provided with a test item on a single occasion); NOTE 7: Proficiency testing is sometimes referred to as “external quality assessment.”
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proficiency testing materials manufacturers organizations that manufacture the materials used in proficiency testing/external quality assessment Project: MM14 NOTE: They may be the contract manufacturers for a quality assessment organization or a laboratory.
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proficiency testing plan written account describing the group of interrelated activities or the system of actions related to proficiency testing aimed at achieving a specific goal(s) or objective(s) within a specific timeframe Project: QMS24
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proficiency testing process set of interrelated activities that starts with the determination of the need for proficiency testing and ends with review of proficiency testing performance. It explains what needs to be done, when, and by whom Project: QMS24
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proficiency testing provider for the purposes of QMS24 and MM14, an organization or laboratory that administers and manages one or several proficiency testing program(s) Project: QMS24, MM14 NOTE 1: This includes selection, distribution, receiving, and analyzing results; reporting back to participants; and reporting to regulatory or accreditation organizations; NOTE 2: A proficiency testing provider may also be a regulatory or accreditation organization; NOTE 3: This includes selection, distribution, receiving and analyzing results; reporting back to participants; and reporting to regulatory or certifying agencies when deemed.
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proficiency testing/external quality assessment a program in which multiple samples are periodically sent to members of a group of laboratories for analysis and/or identification, in which each laboratory’s results are compared to an accepted reference value or to results from other laboratories in the group Project: EP14
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proglottid segments of the tapeworm containing male and female reproductive systems; may be immature, mature, or gravid (Taenia or Diphyllobothrium) Project: M28
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prognostic biomarker biomarker that provides information about a patient’s likely overall cancer outcome, based on the outcomes of previous patients with similar biomarker profiles, symptoms, clinical presentation, demographics, and risk factors Project: MM23, MM26
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prognostic markers indicate the likelihood of a time-dependent outcome (tumor recurrence, metastasis, patient survival) regardless of the specific treatment the patient receives Project: I/LA28 NOTE: For example, in most solid tumors, the spread of cancer cells to lymph nodes is a prognostic marker that indicates an increased likelihood of tumor recurrence no matter which particular form of therapy the patient receives following surgery.
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program plan or system of actions directed at accomplishing a clear objective Project: QMS20, GP48 EXAMPLE: The collection of policies, processes, procedures, forms, and actions that compose a laboratory safety program; NOTE 1: A program is composed of related activities that are organized and managed to accomplish specific outcomes on a continuing basis; NOTE 2: QMS20 describes a “cost of quality” program.
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program group of interrelated activities to accomplish specific outcomes on a continuing basis Project: GP26, QMS16, QMS25, QMS01 Source: Quality Glossary EXAMPLE 1: Safety program, quality control program, training program; EXAMPLE 2: Actions and related documents that constitute a safety program, quality control program, or training program; NOTE: A program is directed at accomplishing a clear objective, including detailed activities to take, by whom, when, and what means or resources to use.
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propagule an individual unit that can give rise to colonial formation Project: M54
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proper shipping name any of over 3000 internationally recognized names of dangerous goods specifically listed by International Air Transport Association Project: M29
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property inherent state- or process-descriptive feature of a system including any pertinent components Project: C51 NOTE 1: A process of a system may be internal or involve the environment; NOTE 2: “Quantity” and “nominal property” are specific concepts under the general generic concept “property”; “quantity” is related to magnitude whereas “nominal property” has no such relation (IUPAC § 5.5).
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property value (of a reference material) value attributed to a quantity representing a physical, chemical, or biological property of a (certified) reference material Project: EP30
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propidium iodine a fluorescent intercalating nucleic acid dye (binds both RNA and DNA) Project: I/LA26 NOTE 1: When bound to nucleic acid, the fluorescence increases several fold with an excitation of approximately 535 nm (typically with a 488 nm argon laser) and an emission maximum of 617 nm; NOTE 2: This dye is membrane impermeant and generally excluded from viable cells; NOTE 3: It is commonly used in flow cytometry applications as a viability marker and also for the measurement of DNA content for cell cycle analyses; NOTE 4: It is commonly combined with other fluorochromes for multiparametric flow cytometry applications.
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proportional error systematic error that is directly proportional to analyte concentration, intensity, or activity. See also accuracy, Bias, Imprecision, Inaccuracy, Precision
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protected health information components of individually identifiable health information, as defined under the Health Insurance Portability and Accountability Act in the United States, transmitted or stored by in vitro diagnostic systems Project: AUTO11
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protein a sequence of > 50 amino acids joined by amide bonds that typically has secondary and tertiary structural features Project: C64
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proteinaceous infectious particle (prion) abnormally folded host membrane protein associated with transmissible spongiform encephalopathies that demonstrates resistance to conventional disinfection and sterilization procedures Project: M29
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proteoform a single molecular form of a protein Project: C64
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proteoforms all molecular forms of a protein Project: C64
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proteolysis-aided determination of protein concentration through the measurement of surrogate peptides Project: C64 NOTE: Surrogate peptides are generated through the deliberate use of a selected protease or defined chemical digestion step.
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proteome the complete expression profile of proteins of an organism Project: MM13
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proteomics the process of defining the proteome Project: C50 NOTE 1: The proteome consists of all proteins in an organism.
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proteomics the study of the proteome by the analysis of the protein structure and composition Project: MM13
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proteotypic peptide a peptide that uniquely identifies a protein and can be routinely observed using tandem mass spectrometry Project: C64
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prothrombin time time required to clot a blood sample once exposed to a thromboplastin reagent material (ISO 17593) Project: ISO 17593, POCT14
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prothrombin time 1) the time in seconds required for a fibrin clot to form in a plasma sample after tissue thromboplastin and an optimal amount of calcium chloride have been added to the sample; 2) time in seconds required for a fibrin clot to form in a plasma sample after optimal amounts of tissue thromboplastin (tissue factor plus phospholipid) and calcium chloride have been added to the sample Project: H21, H54, H47, H57 NOTE 1: Prothrombin time is time in seconds required for a fibrin clot to form in a plasma sample after optimal amounts of tissue thromboplastin (tissue factor plus phospholipid) and calcium chloride are added to the sample; NOTE 2: The prothrombin time measures the extrinsic and common coagulation pathways; NOTE 3: The World Health Organization defines prothrombin time in the following way: prothrombin time (tissue-factor-induced coagulation time) – the clotting time of a plasma (or whole blood) sample in the presence of a preparation of thromboplastin and the appropriate amount of calcium ions (WHO 880); NOTE 4: Per international standards, PT is defined as the “time required to clot a blood sample once exposed to a thromboplastin reagent material” (ISO 17593).
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prothrombin time measuring system measuring system that records the time required for a sample to clot after being exposed to a thromboplastin or tissue-factor derived reagent (ISO 17593) Project: ISO 17593 NOTE: The system includes the reagent plus the instrument used to record the clotting time (ISO 17593).
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prothrombin time ratio the ratio of the prothrombin time of a test plasma divided by the geometric mean of the reference range Project: H47
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prothrombin time test a test used for evaluation of the extrinsic and common coagulation pathway and for monitoring oral anticoagulant therapy NOTE: A coagulation test sensitive to abnormalities of the extrinsic and common coagulation pathway.
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prothrombin time test system test system that records the time required for a blood specimen to clot once exposed to a thromboplastin or tissue-factor derived reagent NOTE The system includes the reagent plus the device used to record the clotting end-point.
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protocol the defined procedure by which a patient with a particular condition should be handled Project: GP49 NOTE: Protocols are often included as parts of clinical trials for which particular data are being collected on every patient. There may also be value-based care protocols that attempt to optimize the use of resources while preserving quality.
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provider in the medical context, a clinical practitioner Project: HS02
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provider in the medical context, a clinical practitioner who may be a physician or nonphysician Project: POCT10 NOTE: In the United States, in the provider-performed microscopy subcategory of moderate complexity in the Clinical Laboratory Improvement Amendments, “provider” is restricted to doctor of medicine, doctor of osteopathy, doctor of podiatric medicine, doctor of dental medicine, nurse practitioner, and nurse midwife.
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proximal nearest; closer to any point of reference (Dorland's Illustrated Medical Dictionary. 33rd ed. Elsevier, Inc.; 2019) Project: PRE02 EXAMPLE: The wrist is proximal to the metacarpal bones.
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proximal deep vein thrombosis intravenous thrombus occurring in the iliac, femoral, or popliteal veins. These veins are in and proximal to the popliteal fossa but do not include superficial (subcutaneous) veins Project: H59
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proxy server a computer process—often used as, or as part of, a firewall—that relays a protocol between client and server computer systems, by appearing to the client to be the server and appearing to the server to be the client (RFC 2828) Project: AUTO09
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prozone effect the result of a suboptimal antigen-antibody reaction in which either the antibody or antigen is in excess, incomplete, or blocks an optimal reaction Project: ILA18, I/LA23, I/LA21
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pseudodeficiency as used in NBS07, a nucleotide change in a gene that codes for an enzyme with low enzyme activity but does not predispose to clinical symptoms Project: NBS07
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pseudogene a section of a sequence that contains an imperfect or nonfunctional sequence with homology to a functional gene Project: MM09, MM17
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pseudohyphae a series of blastoconidia that remain attached to each other forming a hyphal-like filament Project: M54
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PT (POC) the prothrombin time performed using a point-of-care test system
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PT ratio the prothrombin time of a test plasma divided by the geometric mean of the normal prothrombin time reference range NOTE: The prothrombin time ratio is used to calculate the international normalized ratio.
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public key the publicly disclosable component of a pair of cryptographic keys used for asymmetric cryptography (See private key) (RFC 2828) Project: AUTO09
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public-key cryptography the popular synonym for “asymmetric cryptography” (RFC 2828) Project: AUTO09
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Public-Key Cryptography Standards a series of specifications published by Rivest-Shamir-Adleman Laboratories for data structures and algorithm usage for basic applications of asymmetric cryptography (RFC 2828) Project: AUTO09
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public-key infrastructure a system of certification authorities (and, optionally, registration authorities and other supporting servers and agents) that perform some set of certificate management, archive management, key management, and token management functions for a community of users in an application of asymmetric cryptography (RFC 2828) Project: AUTO09
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puck See specimen carrier Project: AUTO12
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pulmonary embolism a material that travels in the venous bloodstream until it lodges in the constriction of the pulmonary arterial system. In H59 the issue is thromboembolism Alternate Term: pulmonary embolus Project: H59
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pulmonary embolus See pulmonary embolism Project: H59
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pulse CO-oximeter a device using multiple wavelengths of light to determine the concentration of hemoglobin derivatives and total hemoglobin (eg, O2Hb, HHb, COHb, MetHb) within a specimen of blood based on noninvasive measurement methods Project: POCT11
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pulse oximeter a noninvasive device that measures wavelengths of light passing through pulsatile arterial blood to estimate the SaO2 and pulse rate Project: POCT11
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pulse oximetry a noninvasive screening test using photoelectric technology to measure oxygen saturation of the blood through the skin Project: NBS03
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pulse rate the pulse rate (PR) value is derived by a pulse oximeter and expressed in beats per minute (bpm) Project: POCT11
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puncture breakage of skin with a sharp-pointed instrument for the purpose of obtaining capillary blood Project: GP42, NBS01
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purgeable organic carbon the concentration of carbon that escapes the sample in the gas phase during the process of sparging the sample to remove inorganic carbon before measuring the organic carbon Project: GP40
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purification separation of nucleic acids according to specific characteristics, for example, molecular weight in electrophoresis Alternate Term: isolation Project: MM03, M55 NOTE: Methods applied are often combinations of extraction, precipitation, chromatography, centrifugation, electrophoresis, or affinity separation.
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purification separation of nucleic acids or proteins from other components of the sample and sample matrix Project: MM22, MM24 NOTE: Methods applied are often combinations of extraction, precipitation, chromatography, centrifugation, electrophoresis, or affinity separation.
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PV1 an Health Level Seven abbreviation for a patient visit segment (HL7 V2.6) Project: AUTO01, AUTO02, AUTO03
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PV2 an Health Level Seven abbreviation for a patient visit with additional information (HL7 V2.6) Project: AUTO01, AUTO02, AUTO03
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pyridinoline pyridinium compound formed during collagen maturation by crosslinking lysine and hydroxylysin side chains from different collagen molecules Alternate Term: hydroxylysylpyridinoline Project: C48
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QC failure result that differs from the expected quality control result Project: M50-A
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quadrupole mass filters the most commonly used mass spectrometers in the clinical laboratory. Quadrupole analyzers have four poles (electrodes) that are energized as pairs (in a square array), each with radio frequency (RF) and direct current (DC) voltages. The RF voltages are set out of phase with one another by 180 degrees, and the DC voltages are of opposite polarity. Ions interact with the electric fields and follow complicated trajectories, so only one m/z range can pass through this device for a given set of voltages. This functional characteristic has led to these analyzers being called mass filters, because they filter out most masses and allow only one specific ion to pass through for any defined set of parameters. This is somewhat analogous to an optical filter. To allow the passage of a range of ions of different m/z values, the voltages are changed, either continuously or stepwise (ie, scanned)
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qualification process to demonstrate the ability to fulfill specified requirements (ISO 15198) Project: ISO 15198 NOTE: The term "qualified" is used to designate the corresponding status.
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qualification the act of establishing with documented evidence that the process, equipment, and/or materials are designed, installed, operated, and performed according to the predetermined specifications Project: GP40
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qualification process by which one provider of laboratory services investigates and determines the capabilities and quality of services offered by another provider Project: QMS05 NOTE: As used in QMS05, the term applies to the process of due diligence by which a referring laboratory assesses the capabilities of prospective referral laboratories.
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qualification process by which a laboratory investigates and determines the capabilities and quality of services offered by a supplier Project: QMS21 NOTE: As used in QMS21, the term applies to the process of due diligence by which a referring laboratory assesses the capabilities of one or more prospective suppliers or referral laboratories.
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qualified examiner a person with special training and recognized skills in blood cell morphology, and who has been qualified as detailed in Sections 6.6.3 through 6.6.5 of CLSI document H20 Project: H44, H20
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qualified technician an individual officially recognized as being trained to perform a particular job Project: QMS23 NOTE: A qualified technician may be certified.
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qualifying ion a specific m/z or transition with a known or determined intensity relationship to a quantifying ion Alternate Term: qualifier Project: C64
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qualitative a characterization applied to laboratory tests that detect and/or identify a particular analyte, constituent, or condition Project: POL1/2, HS02, MM13, I/LA33, H59, POCT04 NOTE 1: This term is applied to tests that detect whether a particular analyte, constituent, or condition is present or absent, and is sometimes assigned a positive degree (ie, 1+, 2+); NOTE 2: The term “semiquantitative” may also be used.
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qualitative a characterization applied to laboratory tests that detect the presence or absence of a particular analyte, constituent, or condition Project: POCT10, H62 NOTE 1: Specific identification may be performed; NOTE 2: Data are descriptive as opposed to numeric and are used to determine characteristics of the test sample. Data are reported in nominal formats (eg, yes/no, multiple genotypes); NOTE 3: An example of a flow cytometric method that reports qualitative data is leukemia/lymphoma immunophenotyping.
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qualitative characterization applied to a test that produces a result that is descriptive rather than numerical Project: POCT08, POCT15 NOTE 1: For example, a urine pregnancy test might generate a result of “positive” or “negative” for urinary human chorionic gonadotropin. In contrast, a quantitative test generates a numerical result; NOTE 2: The quality control and reporting procedures differ significantly for quantitative and qualitative tests: NOTE 3: See quantitative.
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qualitative examination results that do not have a quantitative, numerical result Project: EP12-IG
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qualitative assay an assay system that produces an indication of the presence or absence of an analyte but does not provide a precise estimate of the concentration of that analyte; a positive test result implies only that the assay signal exceeds the analytical threshold or positive cutoff point that has been set to obtain an arbitrary combination of diagnostic sensitivity and specificity Project: I/LA34, I/LA20 NOTE: A positive assay signal should relate to a certain presence of immunoglobulin E antibody specific to the allergen tested in the subject’s blood.
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qualitative assay the assay readout does not have a continuous proportionality relationship to the amount of analyte in a sample; the data are categorical in nature Project: I/LA28 NOTE: Data may be nominal (positive or negative) such as presence or absence of a gene or gene product. Alternatively, data might be ordinal, with discrete scoring scales (1 to 5, − +, +++, etc.), such as immunohistochemistry assays.
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qualitative tests candidate methods that provide only two categorical responses (ie, positive/negative or yes/no) Project: EP39 NOTE 1: Some qualitative tests have no numerical values associated with the results; alternatively, some tests are labeled as qualitative because one of only two results (eg, positive or negative) is reported; these reported results are derived from dichotomizing a quantitative or ordinal scale; NOTE 2: A distinguishing feature of qualitative tests is that they have only one possible medical decision point, at the cutoff.
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quality degree to which a set of inherent characteristics of an object fulfills requirements (ISO 9000) Project: GP26, QMS06, EP23, QMS14, GP23, QMS16, QMS25, QMS01, C40 Source: Quality Glossary
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quality (medical laboratory) a set of well-defined and well-executed processes that create a system for the collection, examination, and reporting of human samples that: supports diagnosis, preventions, and management of disease states; generates information having clinical utility and optimal impact on health outcomes; meets predetermined targets for accuracy, reproducibility, and traceability; strives to minimize error; is timely, safe, efficient, cost effective; and focuses on client satisfaction and continual improvement (ISO/TR 22869) Project: I/LA28
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quality assessment an ongoing mechanism to monitor, assess, and when indicated, correct identified problems Project: EP23
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quality assessment program See proficiency testing Alternate Term: proficiency testing Project: MM14
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quality assurance 1) part of quality management focused on providing confidence that quality requirements will be fulfilled (ISO 9000); 2) a comprehensive set of policies, procedures, and practices used to monitor the laboratory’s entire testing process and ensure that the testing site’s results are reliable Project: GP26, QMS06, EP23, POCT01, VET03, M23, H42, H43, C34, EP18, POCT09, H26, POCT07, I/LA28, QMS01, PRE05, MM19, NBS05, POCT10, POCT12, VET01, POCT14, MM22, GP23, H52, POCT13, M52, QMS21, POCT04, QMS24, VET06, GP48, M02, M07, NBS04, M11, M24, NBS09, MM24, NBS10, POCT16 Source: Quality Glossary NOTE 1: The practice that encompasses all procedures and activities directed toward ensuring that a specified quality of product or service is achieved and maintained. In the testing environment, this process includes monitoring all the raw materials, supplies, instruments, and procedures; sample collection, transport, storage, and processing; recordkeeping; calibrating and maintaining equipment; quality control; proficiency testing; training of personnel; and all else involved in the production of the data reported; NOTE 2: These activities include monitoring, evaluating, taking preventive and corrective actions, if necessary, and monitoring the corrective actions for the preexamination, examination, and postexamination phases; NOTE 3: Quality assurance is also described as a planned and systematic set of quality activities including risk assessment; NOTE 4: Quality assurance includes monitoring, evaluating, and taking corrective actions, if necessary, based on evaluations, and monitoring the corrective actions for preexamination, examination, and postexamination activities. These activities include but are not limited to recordkeeping, calibration and maintenance of equipment, quality control, proficiency testing, and training; NOTE 5: Quality assurance may be said to comprise internal quality assurance and external quality assurance and is interrelated with quality control; NOTE 6: A comprehensive set of policies, procedures, and practices used to monitor the laboratory’s entire testing process and ensure that the testing site’s results are reliable.
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quality assurance the entire institutional plan for ensuring and managing the quality of results or observations reported by point-of-care testing devices (modified from ISO 9000) Alternate Term: QA Project: POCT02
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quality assurance 1) the planned systematic activities necessary to ensure that a component, module, or system conforms to established technical requirements; 2) all actions that are taken to ensure that a development organization delivers products that meet performance requirements and adhere to standards and procedures; 3) the policy, procedures, and systematic actions established in an enterprise for the purpose of providing and maintaining some degree of confidence in data integrity and accuracy throughout the life cycle of the data, which includes input, update, manipulation, and output (ISO/IEC International Standard 812); 4) the actions, planned and performed, to provide confidence that all systems and components that influence the quality of the product are working as expected individually and collectively (HHS Publication FDA 90-4236) Project: AUTO08
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quality assurance process-oriented laboratory practices that are designed to prevent problems Project: MM26 NOTE: These practices include tracking quality metrics over time, regular evaluation of the metrics, and taking preventive and corrective actions, if necessary.
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quality assurance all activities that are consistently performed before testing (eg, patient identification, specimen collection, quality control); during testing (eg, performance of the test according to the procedure); and after testing (eg, reporting of the correct results to the physician and documentation of the correct results in the patient’s chart) that ensure that accurate test results are reported to the health care provider Project: POCT08, POCT15 NOTE 1: Other quality assurance activities include, but are not limited to, proficiency testing, monitoring of temperature logs, monitoring of corrective action logs, and competence assessment of testing personnel; NOTE 2: Part of quality management focused on providing confidence that quality requirements will be fulfilled (ISO 9000).
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quality control part of quality management focused on fulfilling quality requirements (ISO 9000) Project: POCT13, GP26, POCT14, POCT01, GP16, M44, EP18, I/LA33, POCT09, M51, H26, NBS04, POCT07, EP23, EP19, MM19, POCT10, M38, MM22, GP23, M52, VET06, M02, M07, M23, M45, POCT04, EP31, M50, M35, C34, VET01, M11, M24, NBS09, NBS05, MM24, NBS10 NOTE 1: Quality control includes the operational techniques and activities used to fulfill requirements for quality; NOTE 2: In health care testing, the set of procedures designed to monitor the test method and the results to ensure appropriate test system performance, including testing control materials, charting the results and analyzing them to identify sources of error, and evaluating and documenting any remedial action taken as a result of this analysis; NOTE 3: Quality control includes testing quality control materials, charting the results and analyzing them to identify sources of error, and evaluating and documenting any remedial action taken as a result of this analysis; NOTE 4: Quality control includes testing of normal and abnormal control materials, recording the results, identifying sources of error, and evaluating and documenting any corrective action taken; NOTE 5: In medical laboratory testing, quality control includes the procedures intended to monitor the performance of a test procedure to ensure reliable results; NOTE 6: The set of procedures undertaken in a laboratory for the continuous assessment of work carried out in the laboratory and evaluation of tests to decide whether these are reliable enough for release of results to the requesting health care provider. The procedures should include tests on control material, results of which may be plotted on a quantitative control chart showing upper and lower standard deviation-based ranges (eg, ± 1 standard deviation, ± 2 standard deviation, ± 3 standard deviation), and may also include statistical analysis of patient data (eg, moving averages). The main objective is to ensure day-to-day consistency of measurements or observations, if possible, in agreement with an indicator of truth, such as a control material with end-user assigned values; NOTE 7: Quality control is also described as operational techniques and activities that are used to fulfill requirements for quality; NOTE 8: The purpose of quality control is to ensure that all quality requirements are being met; NOTE 9: The set of mechanisms, processes, and procedures designed to monitor the measuring system to ensure the results are reliable for the intended clinical use; NOTE 10: More specifically, it is the set of procedures undertaken in a laboratory for the continuous assessment of work carried out in the laboratory and evaluation of tests to decide whether these are reliable enough for release of results to the requesting health care provider; NOTE 11: In health care testing, the set of procedures based on measurement of a stable material that is similar to the intended patient specimen, to monitor the ongoing performance of a measurement procedure and detect change in that performance relative to stable baseline analytical performance; NOTE 12: A system for ensuring maintenance of proper standards by periodic inspection of the results and the operational techniques that are used to ensure accuracy and reproducibility; NOTE 13: In medical laboratory testing, quality control includes the procedures intended to monitor the performance of a test system to ensure reliable results.
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quality control the operational techniques that are used to ensure accuracy and reproducibility Project: VET03
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quality control (internal) the set of procedures undertaken in a laboratory for the continual assessment of work carried out within the laboratory and evaluation of the results of tests to decide whether the latter are reliable enough for release to the requesting clinician Alternate Term: internal QC Project: H42, H43, H52 NOTE: The procedures should include tests on procedural control material and statistical analysis of patient data. The main object is to ensure day-to-day consistency of measurement or observation that is, if possible, in agreement with an agreed reference, such as control material with assigned values.
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quality control in microbiology, the operational techniques that are used to ensure accuracy and reproducibility Project: VET04
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quality control part of the overall quality assurance plan focused on the periodic guaranteeing consistency in the analytical performance of a point-of-care testing device Project: POCT02 NOTE: Examples of quality control include an internal check performed with each patient sample or the periodic analysis of an external specimen pool (a control) to determine result drift, bias, imprecision, and other trends that would affect the quality of a patient result or observation (ISO 9000).
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quality control 1) the operational techniques and activities that are used to fulfill requirements for quality; 2) in health care testing, the set of procedures designed to monitor the test measurement procedure and the results to ensure test system performance Project: POCT12 NOTE: Quality control includes testing control materials, charting the results and analyzing them to identify sources of error, and evaluating and documenting any action taken as a result of this analysis.
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quality control the set of procedures designed to monitor the test method and the results to ensure appropriate test system performance Project: QMS01, QMS06, QMS07, QMS13, QMS21, QMS23, QMS24 Source: Quality Glossary NOTE: Quality control includes testing quality control materials and charting and analyzing the results.
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quality control the operational techniques that are used to ensure accuracy and reproducibility in microbiology testing Project: M43
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quality control techniques and procedures that are used to ensure an assay meets established performance, including accuracy and reproducibility Project: MM26 NOTE 1: These measures are product-oriented and aimed at identifying problems; NOTE 2: For complex molecular assays, includes a set of quality metrics, which are both common to many assays (eg, depth of coverage) and specific for the assay's indications.
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quality control steps performed either within a test device (internal quality control) or by the testing personnel (external quality control) that ensure that a testing system is performing correctly Project: POCT08, AUTO16, POCT15 NOTE 1: An external control is a device, solution, or lyophilized preparation; NOTE 2: Alternative terms for internal controls include “procedural control,” “onboard control,” and “built-in control.”
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quality control part of the overall quality assurance plan focused on the periodic guaranteeing consistency in the analytical performance Alternate Term: control procedure Project: H62 NOTE 1: The operational techniques and activities that are used to fulfill requirements for quality; NOTE 2: The set of procedures designed to monitor the test method and the results to ensure appropriate test system performance; NOTE 3: Quality control includes testing control materials, charting and analyzing results to identify sources of error, and evaluating and documenting any action taken as a result of this analysis.
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quality control event the occurrence of one or more quality control measurements and a quality control rule evaluation using the quality control results Project: C24 NOTE: This may also be referred to as a quality control evaluation.
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quality control material (assayed or unassayed) a device intended for medical purposes for use in a test system to estimate test precision and to detect systematic analytical deviations that may arise from reagent or analytical instrument variation. A quality control material (assayed and unassayed) may be used for proficiency testing in interlaboratory surveys (21 CFR §862.1660) Project: MM06
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quality control material substance, material, or article intended by its manufacturer to be used to verify the performance characteristics of an in vitro diagnostic medical device Project: POCT13, C40
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quality control plan a document that describes the practices, resources, and sequences of specified activities to control the quality of a particular measuring system or test process to ensure requirements for its intended purpose are met Project: QMS13, EP23 NOTE: An individualized quality control plan is the Clinical Laboratory Improvement Amendments procedure for an alternate quality control option allowed by 42 CFR 493.1250. The Centers for Medicare & Medicaid Services guidance and concepts for individualized quality control plan are a formal representation and compilation of many current laboratory practices to ensure quality test results. Individualized quality control plan permits the laboratory to customize its quality control plan according to test method and use, environment (laboratory setting), and testing personnel while providing for equivalent quality testing.
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quality control plan a document that describes the practices, resources, and sequences of specified activities to control the quality of a particular measuring system or measurement procedure to ensure requirements for its intended purpose are met Project: C24
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quality control program a set of laboratory procedures designed to monitor the analytical process and detect clinically significant errors Project: M53
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quality control range interval of statistically justified acceptable values specified by the manufacturer for results obtained using the quality control material Project: ISO15197 (April 2001)
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quality control result the quantity obtained from a quality control measurement Project: C24
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quality control rule decision criteria used to determine if a given quality control observation should be accepted or rejected
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quality control rule decision criteria used in the process of deciding whether a measurement procedure is operating within its stable (in-control) state Project: C24
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quality control rule evaluation the process of deciding whether a measurement procedure is operating in its stable (in-control) state by applying a quality control rule to a set of quality control results Project: C24
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quality control sample a stable sample designed to monitor performance of a test system that is intended to measure patient sample measurands and hence simulate the response of the test system to a patient specimen matrix Project: EP23
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quality control solution solution that contains a known amount of glucose and is used to check that the meter and the test strips are working properly Project: POCT13
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quality control strategy the number of control materials, the number of measurements to be made on those materials, the location of those control materials in an analytical run, and the statistical quality control rules applied
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quality control strategy the number of quality control materials to measure, the number of quality control results and the quality control rule to use at each quality control event, and the frequency of quality control events Project: C24 NOTE: May also be be referred to as quality control procedure.
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quality control strategy the occurrence of one or more the number of quality control materials to measure, the number of quality control results and the quality control rule to use at each quality control event, and the frequency of quality control events NOTE: May also be referred to as quality control procedure.
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quality costs the total of prevention and appraisal costs and internal and external failure costs related to the quality of a product or service Project: QMS20
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quality improvement part of quality management focused on increasing the ability to fulfill quality requirements (ISO 9000 [3.2.12]) Project: QMS06, QMS14 NOTE 1: Quality improvement is also described as the continuous process of seeking opportunities for system improvement based on the planned processes of monitoring, interpretation, implementation of required action for change, and remonitoring; NOTE 2: This is often described in the terms referred to as the Deming Cycle (plan-do-check-act).
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quality indicator a numerical tool to quantify the quality assurance by plotting total number (or percent of total) of errors and errors due to a specific preexamination, examination, or postexamination cause against time on a graph Project: POCT07 NOTE: Indicate dates at which a change happened, eg, introducing liquid quality control, implementing a new device, changing the reagents’ source, or having a training session.
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quality indicator measurement (metric) to monitor specific activities as part of the quality management system Project: MM20
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quality indicator observations, statistics, or data defined by the organization or service that typify the performance of a given work process and provide evidence that the organization or service is meeting its quality intentions Project: QMS01, QMS12, QMS19, QMS12, GP23, GP26, QMS06 Source: Quality Glossary NOTE 1: Also referred to as “key performance indicator” or “quality metric”; NOTE 2: Also referred to as “key performance indicator” or “quality metric” and may be reported in various formats, such as a dashboard or scorecard.
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quality management management with regard to quality (ISO 9000) Project: ISO 9000, QMS06, GP26, QMS07, EP18, QMS16, QMS24 NOTE 1: Management with regard to quality generally includes establishment of the quality policy and quality objectives, quality planning, quality control, quality assurance, and quality improvement; NOTE 2: Management can include establishing policies and objectives, and processes to achieve these objectives (modified from ISO 9000).
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quality management all activities of the overall management function that determine quality policy objectives and responsibilities; and implement them by means such as quality planning, quality control, quality assurance; and quality improvement within the quality system (ISO 8402, 3.2) Project: ISO 8402
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quality management the overall strategy and/or system in which quality control and/or quality assurance functions are implemented. Quality management plans also include guidance for new product development Project: MM26
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quality management coordinated activities to direct and control an organization with regard to quality (modified from ISO 9000) Project: QMS14, QMS03
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quality management plan a document or system focused on setting quality objectives and specifying necessary operational processes and related resources to fulfill the quality objectives
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quality management system part of a management system with regard to quality Project: GP26, EP18, POCT07, EP23, MM20, GP23 NOTE 1: Systematic and process-oriented efforts are essential to meet quality objectives; NOTE 2: The “quality” referred to in this definition relates to matters of both management and technical competence (ISO 15189); NOTE 3: A quality management system typically includes the organizational structure, resources, processes, and procedures needed to implement quality management; NOTE 4: These principles include the following categories: Organization and Leadership, Customer Focus, Facilities and Safety Management, Personnel Management, Supplier and Inventory Management, Equipment Management, Process Management, Documents and Records Management; Information Management, Nonconforming Event Management, Assessments, and Continual Improvement.
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quality management system organizational structure, responsibilities, policies, processes, procedures, and resources to direct, control, and improve an organization with regard to quality in a systematic and process-oriented manner (modified from 21 CFR 820) Project: QMS01, QMS06, QMS11, QMS14, QMS16, QMS17, QMS21, QMS25, QMS03, QMS22 NOTE 1: Systematic and process-oriented efforts are essential to meet quality objectives; NOTE 2: The term “quality management system” referred to in this definition relates to general management activities; the provision and management of resources; the preexamination, examination, and postexamination processes; and evaluation and continual improvement.
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quality manual description of an organization’s quality management system (modified from ISO 9000) Project: QMS01 Source: Quality Glossary NOTE: Quality manuals can vary in detail and format to suit the size and complexity of an individual organization (ISO 9000).
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quality monitoring ongoing quality assessment process that establishes the most important monitoring targets to ensure the organization's ability to provide optimal customer satisfaction Project: QMS06
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quality plan a document or system focused on setting quality objectives and specifying necessary operational processes and related resources to fulfill the quality objectives
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quality plan specification of the procedures andassociated resources to be applied when and by whom to a specific object (ISO 9000) Project: QMS14 NOTE: These procedures generally include those referring to quality management processes and to product and service realization processes (ISO 9000).
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quality planning activity of setting quality goals and objectives and identifying related processes and resources (modified from ISO 9000) Project: QMS06, QMS01, QMS14 Source: Quality Glossary NOTE: Establishing quality plans can be part of quality planning (ISO 9000).
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quality policy overall intentions and direction of an organization related to quality as formally expressed by organizational leadership (modified from ISO 9000) Project: QMS01, GP26, QMS16 Source: Quality Glossary NOTE 1: Generally, the quality policy is consistent with the overall policies of an organization and provides a framework for setting quality objectives (modified from ISO 9000); NOTE 2: Quality management principles presented in ISO 9000 can form a basis for the establishment of a quality policy.
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quality report report compiled periodically that summarizes various aspects of a laboratory’s performance for the purpose of management review Project: QMS14
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quality requirement specification of the characteristics necessary for a product or service to be fit for its intended use Project: C24 NOTE: For a laboratory measurement procedure, the quality requirement is usually expressed in terms of an allowable total error. If the measurement error in a patient’s result exceeds the total error, the result fails to meet its quality requirement.
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quality system the organizational structure, resources, processes, and procedures needed to implement quality management (ISO 8402, 3.6) Project: ISO 8402
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quality system the organizational structure, responsibilities, procedures, processes, and resources for implementing quality management
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quality system essentials the components of a management infrastructure necessary to support any health care organization’s or service’s path of workflow Project: GP26, QMS01, QMS06, QMS06, QMS07, GP23, QMS17 Source: Quality Glossary
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quality system essentials coordinated management activities to direct and control an organization with regard to quality (derived from ISO 9000); set of coordinated building blocks for quality management Project: MM19
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quality system essentials a set of interrelated processes for quality management that support and form the foundation for the laboratory’s path of workflow Project: MM20
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Quality System Regulation revision of Good Manufacturing Practice regulation 21 CFR 820 (US Food, Drug and Cosmetic Act) that added design controls, production controls, process validation, and quality assurance documentation as requirements to the manufacture of medical devices and in vitro diagnostic products Alternate Term: QSR Project: M50
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quality teamwork a quality system-based teamwork process that focuses on the most effective and efficient organization-wide, anticipatory decision making
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quality tools methods and techniques used to generate, analyze, interpret, and present quality data
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quality value a measure of base-call accuracy in a sequence Project: MM18 NOTE: Often represented by the PHRED score.
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quality-adjusted life years an outcome measure that incorporates the quality or desirability of a health state with the duration of survival Project: GP45 NOTE: The quality of life is integrated with the length of life by using a multiplicative formula.
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quantification cycle a generic term for the fractional cycle number used in real-time quantification that is derived by any method (eg, threshold or shape). Quantification cycle is inversely proportional to the log of the initial template concentration Project: MM06
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quantifying ion a specific m/z or transition that is used to derive a quantitative measurement Alternate Term: quantifier Project: C64
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quantile (fractile) 1) one of the class of values of a variate that divides the total frequency of a sample or population into a given number of equal proportions (RHUDCD1.7); 2) the p-quantile is the value of the random variable for which the distribution function equals “p” (0 < p < 1) Project: ISO3534-1-1.14
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quantile the fractile of a random variable or probability distribution (ISO 3534-1-1.14) Project: ISO3534-1-1.14 NOTE: The p-quantile is the value of the random variable for which the distribution function equals p (0 < p < 1).
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quantitative a characterization applied to laboratory tests that give results expressing a numerical amount or level (ie, concentration) of an analyte in a specimen Project: POL1/2, MM13, H59, I/LA28, POCT04 NOTE 1: The level of analyte is usually compared with an accredited recognized standard; NOTE 2: This is in contrast to qualitative tests.
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quantitative characterization applied to a test that produces a numerical result Project: POCT08, POCT15 NOTE 1: For example, a point-of-care blood glucose test might generate a result of 120 mg/dL. In contrast, a qualitative test generates a non-numerical result such as “positive” or “detected”; NOTE 2: A subset of quantitative tests called semiquantitative provide results either over a range of values, such as a urine dipstick that results in glucose ranges of 0 to 40 mg/dL, 40 to 100 mg/dL, and >100 mg/dL, or as a series of relative values, such as the same multiple test urine dipstick that results in hemoglobin as 0, +, ++, +++, and ++++; NOTE 3: See qualitative.
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quantitative relating to a measurement that provides a numerical amount of the substance being measured Project: MM09, MM17
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quantitative assay an assay system that produces an accurate and reproducible estimate of the concentration of an analyte, such as immunoglobulin E antibody, in the test specimen; its analysis can use homologous or heterologous interpolation from a calibration curve, which is referenced to a readily available standard reference preparation Project: I/LA34, I/LA20 NOTE: The units reported from quantitative assays for total serum immunoglobulin E are traceable to a defined serum standard (eg, World Health Organization standard material 75/502) that is available to all assay manufacturers. Because of the general absence of calibrated homologous human immunoglobulin E antibody standards, current quantitative assays for immunoglobulin E antibody can be calibrated by heterologous interpolation from a total human serum immunoglobulin E reference curve. Quantitative assays tend to be among the most complex tests (eg, immunoassays) and their results can be reported in gravimetric (ng/mL [total serum immunoglobulin E assays]) or international units (IU/mL [total immunoglobulin E assays] or Iua/mL [allergen-specific immunoglobulin E antibody assays]), where 1 IU is equivalent to 2.42 ng of immunoglobulin E. The first allergen-specific immunoglobulin E assay developed in 1967 was the radioallergosorbent test, which employed a calibration system based on arbitrary units (eg, PRU/mL, AU/mL) and produced, at best, semiquantitative immunoglobulin E antibody results. These assays were not automated. Gradually, allergen-specific immunoglobulin E assays evolved with manual pipetting and a defined accessible calibrator that is based on a widely available reference material (eg, World Health Organization standard material 75/502). This assay quantified immunoglobulin E in units that were directly related to the amount of immunoglobulin E antibody that was present in the specimen. Current assays have evolved into quantitative assays that involve full “walk away” automated platform instrumentation. These assays represent the most precise, rapid, and quantitative assay designs available for immunoglobulin E antibody measurement.
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quantitative assay an assay system that produces an accurate and reproducible estimate of the concentration of the measurand in the test specimen; its analysis uses homologous or heterologous interpolation from a calibration curve, which is referenced to a readily available standard reference preparation
Project: H62
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quantitative polymerase chain reaction a quantitative polymerase chain reaction assay designed to detect gene copy number Project: MM05
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quantity property of a phenomenon, body, or substance, for which the property has a magnitude that can be expressed as a number and a reference (JCGM 200:2012) Project: ISO IEC Guide 99, POCT07, C58, C51, C56, C49 NOTE 1: The generic concept ‘quantity’ can be divided into several levels of specific concepts, as shown in the following table. The left hand side of the table shows specific concepts under ‘quantity.’ These are generic concepts for the individual quantities in the right hand column (JCGM 200:2012); NOTE 2: A reference can be a measurement unit, a measurement procedure, a reference material, or a combination of such (JCGM 200:2012); NOTE 3: Symbols for quantities are given in the ISO 80000 and IEC 80000 series Quantities and units. The symbols for quantities are written in italics. A given symbol can indicate different quantities (JCGM 200:2012); NOTE 4: The preferred IUPAC-IFCC format for designations of quantities in laboratory medicine is “System—Component; kind-of-quantity”; EXAMPLE: “Plasma (Blood)⎯Sodium ion; amount-of-substance concentration equal to 143 mmol/L in a given person at a given time” (JCGM 200:2012); NOTE 5: A quantity as defined here is a scalar. However, a vector or a tensor, the components of which are quantities, is also considered to be a quantity (JCGM 200:2012); NOTE 6: The concept ‘quantity’ may be generically divided into, eg, ‘physical quantity,’ ‘chemical quantity,’ and ‘biological quantity,’ or base quantity and derived quantity (JCGM 200:2012); NOTE 7: The term “quantity” should not be confused with the term “amount.” The term “quantity” is often used for “kind of quantity” (JCGM 200:2008 § 1.1).
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quantity (of dimension one) quantity in the dimensional expression of which all the exponents of the dimensions of the base quantities reduce to zero Alternate Term: dimensionless quantity EXAMPLES: Linear strain, friction factor, Mach number, refractive index, mole fraction (amount-of-substance fraction), mass fraction.
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quantity calculus set of mathematical rules and operations applied to quantities other than ordinal quantities (JCGM 200:2012) Project: ISO IEC Guide 99 NOTE: In quantity calculus, quantity equations arepreferred to numerical value equations becausequantity equations are independent of the choice ofmeasurement units, whereas numerical value equationsare not (see ISO 31-0:1992, 2.2.2) (JCGM 200:2012).
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quantity dimension expression of the dependence of a quantity on the base quantities of a system of quantities as a product of powers of factors corresponding to the base quantities, omitting any numerical factor (JCGM 200:2012) Alternate Term: dimension of a quantity; dimension Project: ISO IEC Guide 99 EXAMPLE 1: In the ISQ, the quantity dimension of force is denoted by dim F = LMT-2; EXAMPLE 2: In the same system of quantities, dim ����B = ML-3 is the quantity dimension of mass concentration of component B, and ML-3 is also the quantity dimension of mass density, ����, (volumic mass); EXAMPLE 3: The period T of a pendulum of length l at a place with the local acceleration of free fall g is T =2 l g = π or T=C(g) l where C(g) 2 g = π Hence dim C(g) = L-1/2 T (JCGM 200:2012); NOTE 1: A power of a factor is the factor raised to an exponent. Each factor is the dimension of a base quantity (JCGM 200:2012); NOTE 2: The conventional symbolic representation of the dimension of a base quantity is a single upper case letter in roman (upright) sans-serif type. The conventional symbolic representation of the dimension of a derived quantity is the product of powers of the dimensions of the base quantities according to the definition of the derived quantity. The dimension of a quantity Q is denoted by dim Q (JCGM 200:2012); NOTE 3: In deriving the dimension of a quantity, no account is taken of its scalar, vector, or tensor character (JCGM 200:2012); NOTE 4: In a given system of quantities, quantities of the same kind have the same quantity dimension, quantities of different quantity dimensions are always of different kinds, and quantities having the same quantity dimension are not necessarily of the same kind (JCGM 200:2012); NOTE 5: Symbols representing the dimensions of the base quantities in the ISQ are: Base quantity Symbol for dimension length mass time electric current thermodynamic temperature amount of substance luminous intensity L M T I Θ N J Thus, the dimension of a quantity Q is denoted by dim Q = Lα Mβ Tγ Iδ Θε Nζ Jη where the exponents, named dimensional exponents, are positive, negative, or zero (JCGM 200:2012).
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quantity equation mathematical relation between quantities in a given system of quantities, independent of measurement units (JCGM 200:2012) Project: ISO IEC Guide 99 EXAMPLE 1: Q1 = ζ Q2 Q3 where Q1, Q2, and Q3 denote different quantities, and where ζ is a numerical factor (JCGM 200:2012); EXAMPLE 2: T = (1/2) mv2 where T is the kinetic energy and v the speed of a specified particle of mass m (JCGM 200:2012); EXAMPLE 3: n = It/F where n is the amount of substance of a univalent component, I is the electric current, and t the duration of the electrolysis, and where Fis the Faraday constant (JCGM 200:2012).
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quantity of dimension one quantity for which all the exponents of the factors corresponding to the base quantities in its quantity dimension are zero (JCGM 200:2012) Alternate Term: dimensionless quantity Project: ISO IEC Guide 99 NOTE 1: The term “dimensionless quantity” is commonly used and is kept here for historical reasons. It stems from the fact that all exponents are zero in thesymbolic representation of the dimension for such quantities. The term “quantity of dimension one” reflects the convention in which the symbolic representation ofthe dimension for such quantities is the symbol 1 (see ISO 31-0:1992, 2.2.6) (JCGM 200:2012); NOTE 2: The measurement units and values of quantities of dimension one are numbers, but such quantities convey more information than a number (JCGM 200:2012); NOTE 3: Some quantities of dimension one are defined as the ratios of two quantities of the same kind; NOTE 4: Numbers of entities are quantities of dimension one; EXAMPLES: Plane angle, solid angle, refractive index, relative permeability, mass fraction, friction factor, Mach number, number of turns in a coil, number of molecules in a given sample, degeneracy of the energy levels of a quantum system (JCGM 200:2012).
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quantity value number and reference together expressing magnitude of a quantity (JCGM 200:2012) Alternate Term: value of a quantity; value Project: ISO IEC Guide 99, C51, C56, QMS24 EXAMPLE 1: Length of a given rod: 5.34 m or 534 cm (JCGM 200:2012); EXAMPLE 2: Mass of a given body: 0.152 kg or 152 g (JCGM 200:2012); EXAMPLE 3: Curvature of a given arc: 112 m−1 (JCGM 200:2012); EXAMPLE 4: Celsius temperature of a given sample:−5°C (JCGM 200:2012); EXAMPLE 5: Electric impedance of a given circuit element at a given frequency, where j is the imaginary unit: (7 + 3j) Ω(JCGM 200:2012); EXAMPLE 6: Refractive index of a given sample of glass: 1.32 (JCGM 200:2012); EXAMPLE 7: Rockwell C hardness of a given sample (150 kg load): 43.5HRC(150 kg) (JCGM 200:2012); EXAMPLE 8: Mass fraction of cadmium in a given sample of copper: 3 μg/kg or 3 × 10-9 (JCGM 200:2012); EXAMPLE 9: Molality of Pb2+ in a given sample of water: 1.76 μmol/kg(JCGM 200:2012); EXAMPLE 10: Arbitrary amount-of-substance concentration of lutropin in a given sample of plasma (WHO international standard 80/552): 5.0 International Unit/l (JCGM 200:2012); NOTE 1: According to the type of reference, a quantity value is either
— a product of a number and a measurement unit (see Examples 1, 2, 3, 4, 5, 8 and 9); the measurement unit one is generally not indicated for quantities of dimension one (see Examples 6 and 8), or
— a number and a reference to a measurement procedure (see Example 7), or
— a number and a reference material (measurement standard, calibrator) (see Example 10) (JCGM 200:2012); NOTE 2: The number can be complex (see Example 5) (JCGM 200:2012); NOTE 3: A quantity value can be presented in more than one way (see Examples 1, 2 and 8) (JCGM 200:2012); NOTE 4: In the case of vector or tensor quantities, each component has a quantity value (JCGM 200:2012); EXAMPLE: Force acting on a given particle, eg, in Cartesian components (Fx; Fy; Fz) = (−31.5; 43.2; 17.0) N (JCGM 200:2012).
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quantity-value scale ordered set of quantity values of quantities of a given kind of quantity used in ranking, according to magnitude, quantities of that kind (JCGM 200:2008) Alternate Term: measurement scale Project: ISO IEC Guide 99 EXAMPLE 1: Celsius temperature scale (JCGM 200:2012); EXAMPLE 2: Time scale (JCGM 200:2012); EXAMPLE 3: Rockwell C hardness scale (JCGM 200:2012).
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quantum fluorescence yield (quantum yield of fluorescence) the ratio of light quanta that are emitted as fluorescence to the number of quanta that are absorbed by a fluorescer Project: DI01
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quantum yield the probability that absorption of an excitation photon results in emission of a fluorescence photon Project: I/LA24
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quarantine the restriction of activities and/or separation from others of suspect persons who are not ill or of suspect baggage, containers, conveyances, or goods in such a manner as to prevent the possible spread of infection or contamination Project: POCT16
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quasiquantitative continuous numeric data expressed in terms that are characteristic of the test samples but are not derived from an authoritative calibration curve or standard reference material Project: H62 NOTE 1: The prefix “quasi” refers to some resemblance to or possession of certain attributes; NOTE 2: The definition for the term “semiquantitative” is similar to the definition for “quasiquantitative”; however, ordinal data are also considered semiquantitative; NOTE 3: Quasiquantitative data do not include the ordinal data format; NOTE 4: Published recommendations from the biopharmaceutical community use “quasiquantitative”; NOTE 5: Publications regarding the validation of flow cytometric methods use both “quasiquantitative” and “semiquantitative”; NOTE 6: See semiquantitative and ordinal.
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quasi-quantitative assay a quasi-quantitative assay system provides an additional option over the qualitative assay in terms of defining the magnitude of the response. The variations in the positive signal detected by the assay are commonly presented in terms of a series of increasing grades or classes (eg, I to VI, low to high); in arbitrarily defined units per milliliter determined relative to a supplier-specific heterologous dose-response curve or an end-point dilution at which the assay signal becomes negative (eg, titer); or in comparison to a qualitative grading scheme (eg, color chart) Project: I/LA34
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quasispecies the existence of many genetically distinct viral variants that evolve from the initial virus inoculums. For HIV-1, this is due in large part to the lack of proofreading capabilities of the reverse transcriptase, so the new copy differs from the parent genome on average by a single nucleotide. The term quasispecies also applies to other viruses including hepatitis C virus Project: MM06
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quencher any molecular species that reduces the radiance measured from an emitting molecular species (generally applied to fluorescence emission) Project: I/LA23
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quencher molecule that can accept energy from a fluorophore and dissipate the energy by either proximal or fluorescence resonance energy transfer quenching Project: MM03 NOTE: Proximal quenching occurs when the fluorophore and quencher are in close proximity and transferred energy from the fluorophore to the quencher is dissipated as heat.
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quiet zone in automation, the white {blank} space on a bar code immediately preceding the first bar and immediately following the last bar Project: AUTO01, AUTO07, AUTO02, AUTO12
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quiet zone areas directly adjacent to symbols that, according to published symbology standards, must be the same color or appearance as the "spaces" in the symbol and free of any printing Project: AUTO14 NOTE 1: On linear (one-dimensional) symbols, quiet zones must typically be present before and after the symbol; NOTE 2: On two-dimensional symbols, the quiet zones must typically be present on all four sides of a symbol; NOTE 3: The size of the quiet zones is expressed in whole multiples of the X-dimension. Examples of recommended minimum quiet zones include:
Code 128 and most other linear (one-dimensional) symbologies: 10 × the X-dimension
Data Matrix: 4 × the X-dimension is recommended by the Data Matrix standard, but 4× is required for CLSI AUTO14. The Data Matrix standard states that a minimum 1× quiet zone must be present.
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racking act of vigorously dragging test sample tubes back and forth across a metal or hard plastic tube rack so as to vibrate or sonicate cells into single cell suspensions and to reduce cell aggregates Project: H52 NOTE: This movement should be repeated four to six times to achieve the desired effect.
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radiant panel heating panel usually mounted to a ceiling or wall that heats a small area in close proximity to as much as 7°C (45°F) warmer than the surrounding areas
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radiant power the time rate of flow of electromagnetic radiant energy Project: I/LA24 NOTE 1: Radiant power is usually expressed in watts, ie, joules per second; NOTE 2: Radiant Flux is an equivalent deprecated term still used in the context of light as a photon stream.
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radioactive waste 1) substances that are radioactive at levels above the exempt limits (more than 0.05 mCi) established by the Nuclear Regulatory Commission; 2) low-level radioactive waste – defined in the Federal Low-Level Radioactive Waste Policy Act of 1980 as radioactive waste that is not classified as high-level, transuranic, spent fuel, or certain byproduct material (the waste types within the domain of nuclear power plants and fuel facilities) Project: GP05, QMS28 NOTE 1: This waste is generated from the use of radioactive materials; NOTE 2: Low-level radioactive waste is a broad and somewhat ambiguous category, defined not by what it is, but by what it is not; NOTE 3: Most generators of infectious and medical waste generate only low-level radioactive waste.
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radioallergosorbent test the acronym “RAST” should now be considered a historic term, since radioisotopes are rarely used today in clinical assays for IgE antibody Alternate Term: RAST NOTE: In 1967, the RAST was developed as the first immunoassay system available for the measurement of human IgE antibodies to defined allergen specificities in serum. In its original form, the RAST employed a paper disc solid phase to which allergen was covalently attached (allergosorbent) to bind allergen-specific antibodies of all isotypes (primarily IgE, IgG, IgA) from serum. Following a buffer wash to remove unbound serum proteins, bound IgE was detected with I125-labeled polyclonal antihuman IgE. Results were reported in log-related classes or in arbitrary units by interpolation from a heterologous IgE antibirch pollen reference curve. Many minor modifications of this original assay format have been commercialized and they are discussed in the text. When referring to serological IgE antibody assays, the term RAST should no longer be used as a generic descriptor to refer to an IgE antibody assay unless it describes a radioisotopic allergosorbent assay for human IgE antibody.
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radioallergosorbent test the acronym “RAST” should now be considered a historic noncompetitive, solid phase immunoradiometric assay for immunoglobulin E antibody, because radioisotopes are rarely used today, but it serves as the basic assay format for drug-specific immunoglobulin E antibody assays Project: I/LA34
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radioimmunoassay an analytical procedure in which an antibody and a radio-labeled analyte are used to measure the amount of analyte in a sample Project: LA01, C45
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radiolabeling the process of incorporating a radionuclide into, or covalently linking it with an analyte Project: LA01
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radiological refers to a device or incident associated with harm due to the release or dissemination of radioactive materials Project: GP36 NOTE: To be distinguished from “nuclear” as used in the acronym “CBRNE” (“chemical, biological, radiological, nuclear, and explosive”).
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radiometry the science of measuring optical radiation Project: I/LA24 NOTE: Optical radiation is electromagnetic energy commonly referred to as light, encompassing wavelengths from 10 to 1 000 000 nm and divided into regions called ultraviolet, visible, and infrared.
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radionuclide natural or synthetically produced unstable nucleus of an atom that emits ionizing radiation (ISO 15190) Project: ISO 15190
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random In Statistics, of or characterizing a process of selection in which each item of a set has an equal probability of being chosen (RHUD1.7CD)
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random error result of a measurement minus the mean that would result from an infinite number of measurements of the same measurand carried out under repeatability conditions NOTE 1: Random error is equal to error minus systematic error. NOTE 2: Because only a finite number of measurements can be made, it is possible to determine only an estimate of random error. (VIM93)
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random error difference between a particular result of a measurement and the mean result that would be observed from an infinite number of measurements of the same measurand carried out under repeatability conditions (VIM93)
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random error the nondirectional, patternless differences between successive results obtained with an analytical process
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random error of measurement See random error Alternate Term: random error; random measurement error. Project: C51
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random measurement error See random error Alternate Term: random error; random error of measurement Project: C51
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random specimen a specimen collected at an unspecified time
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random specimen-dependent interference variability caused by the presence of different concentrations of interfering substances in a population of patient specimens NOTE 1: Random interference is quantified as the standard deviation of the biases of individual patient specimens; NOTE 2: It is a component of Sy.x in regression analysis, and can be a significant contributor to total random error.
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random specimen-dependent interference variability caused by the presence of different concentrations of influence quantities in a population of patient specimens Project: C56 NOTE: Random interference is quantified as the standard deviation of the biases of individual patient specimens.
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randomization in a randomized trial, the process of assigning participants to groups such that each participant has a known and usually an equal chance of being assigned to a given group Project: GP45 NOTE: Randomization is intended to ensure that the group assignment cannot be predicted.
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randomized blinded trial an experimental study design in which study subjects are allocated at random to interventions and study subjects are not aware of the intervention to which they have been allocated; additionally, study investigators or study personnel making outcomes measurements may also be unaware of the intervention to which study subjects have been allocated Project: GP45 NOTE: Random allocation controls confounding by known and unknown factors and blinding controls bias in study subjects reporting, study personnel measurements of outcomes, and investigators’ analysis of study findings.
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randomly timed glucose See nonfasting glucose Alternate Term: casual glucose; nonfasting glucose Project: POCT13
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range a measure of dispersion which is (ASQC3-99) the difference between the largest and the smallest observed value of a quantitative characteristic (ISO 3534-1-2.30) in a given sample Project: ISO3534-1-2.30, VET03, VET04
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range of a nominal indication interval absolute value of the difference between the extreme quantity values of a nominal indication interval (JCGM 200:2012) Project: ISO IEC Guide 99 EXAMPLE: For a nominal indication interval of −10 V to +10 V, the range of the nominal indication interval is 20 V (JCGM 200:2012); NOTE: Range of a nominal indication interval is sometimes termed "span of a nominal interval" (JCGM 200:2012).
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range of indication set of values bounded by the extreme indications NOTE 1 For an analogue display this may be called the scale range.
NOTE 2 The range of indications is expressed in the units marked on the display, regardless of the units of the measurand, and is normally stated in terms of its lower and upper limits, for example, 100 °C to 200 °C. (VIM93) NOTE 3 See 5.2 Note.
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rapid test single-use analytical device that produces results in less than 30 minutes Project: M53
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rapidly growing mycobacteria mycobacteria that produce colonies on solid media in seven days or fewer when subcultured to appropriate media (eg, Löwenstein-Jensen media) Project: M48
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rare event analysis analysis of cells present at low frequencies, such as stem cell enumeration or detection of minimal residual disease Project: H42, H43
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rare event analysis analysis of cells present at low frequencies, typically less than 1% (one cell in 100), such as glycosyl-phosphatidylinositol–deficient cells in myelodysplastic syndromes or paroxysmal fetal hemoglobinuria or fetal cells in fetomaternal hemorrhage Project: H52
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rate immunoassay an immunoassay in which the analyte is measured by a change in signal with respect to time
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rate of change (RoC) of a function over a time interval the change in function value divided by the elapsed time Project: POCT05 EXAMPLE: The glucose RoC is computed as ΔG ÷Δt.
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rated operating condition operating condition that must be fulfilled during measurement in order that a measuring instrument or measuring system perform as designed (JCGM 200:2008) Project: ISO IEC Guide 99 NOTE: Rated operating conditions generally specify intervals of values for a quantity being measured and for any influence quantity (JCGM 200:2012).
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rated operating conditions conditions of use for which specified metrological characteristics of a measuring instrument are intended to lie within given limits (VIM93) Project: VIM93 NOTEThe rated operating conditions generally specify ranges or rated values of the measurand and of the influence quantities.
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ratio a comparison between two numbers or quantities using division
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ratiometric any system in which an output is directly proportional to an input
Project: H62
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reactive ingredient component that participates in the reaction used to measure or detect the analyte (ISO/CD 18112-1) Project: ISO CD 18112-1 NOTE Reactive ingredient is sometimes referred to as “active” ingredient.
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reactive ingredient constituent that participates in a chemical reaction intended to detect or measure a quantity (ISO 18113-1)
Project: ISO 18113-1, ISO 18113-2, ISO 18113-3 NOTE 1: Constituents such as buffers, preservatives and stabilisers that do not participate in the chemical reaction are not considered reactive ingredients (ISO 18113-1); NOTE 2: Adapted from EN 375:2001, definition 3.1 (ISO 18113-1); EXAMPLES: Antibodies, specific viral nucleotide sequences, enzyme substrates (ISO 18113-1).
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reactivity the qualitative assessment of binding of an antigen or antibody with another substance Alternate Term: immunoreactivity Project: ILA18, I/LA28, MM04 NOTE: “Reactive” is sometimes used as a synonym for “positive” when reporting test results.
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reagent 1) part of the in vitro diagnostic medical device that produces a signal through a chemical or electrochemical reaction, which enables the quantity (eg, prothrombin time) to be detected and its value measured in a sample (ISO 17593); 2) a substance that produces a chemical reaction in a sample that allows an analyte to be detected and/or measured Project: ISO 17593, POCT14, POCT04, EP47
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reagent a substance or supplementary solution added to a microbial identification system that produces a biochemical reaction with a microorganism and allows a product or byproduct of that microorganism to be detected and/or measured Project: M50
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reagent substance that produces a chemical reaction in a sample that enables an analyte to be detected and/or measured Project: AST02, HS02, EP26
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reagent a substance that produces a chemical reaction in a sample that allows an analyte to be detected and measured Project: POCT10
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reagent blank a sample made up of only the method reagents and filter paper NOTE: This sample is used to detect carryover.
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reagent blank a blank that incorporates only the reagents, or the reagent without a particular component of the reagent
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reagent carryover effect a quantifiable change in the sample measurement result caused by carryover Project: EP47
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reagent lot a discrete number of units of disposables [reagent strips or sensors] for testing, which the manufacturer asserts gives equivalent performance for all units contained in the lot
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reagent manufacturers See test manufacturers Alternate Term: test manufacturers Project: MM14
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reagent red blood cells a preparation of human red blood cells used to detect or identify human blood group antibodies (CFR definition) Project: I/LA33
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reagent strip a plastic strip to which is affixed various reaction pads for the qualitative or semiquantitative assay of specific chemical constituents (eg, glucose, protein) or physical parameters (eg, pH, specific gravity) Project: GP16 NOTE: Following exposure to urine, these reaction pads are interpreted visually or evaluated with a reagent strip reader instrument.
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reagent system part of the in vitro diagnostic medical device that produces a signal via a chemical or electrochemical reaction, which allows the analyte (eg, glucose) in a sample to be detected and its concentration measured (modified from ISO 15197) Project: ISO 15197
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reagent water water purified and classified for specific analytical uses NOTE: There are several general categories of reagent water; 1) type I The “ideal” water that can be produced with currently available water-treatment and/or purification technology, and is characterized at the time of production; it should be used in test methods that require minimal interference, or when lack of interference from water of lesser purity cannot be documented or inferred. Type I water may be stored and used in many high-quality analytical applications; however, during storage, deterioration of some Type I properties occurs and should be considered, depending on the particular analysis in which it is used; 2) type II Water in which the presence of bacteria can be tolerated and which should be used for routine test methods for which requirements leading to the choice of Type I or special waters do not apply; 3) type III Water that can be used for washing glassware, for preliminary rinsing of glassware, and as feedwater for producing a higher grade water; 4) special reagent water, Reagent water designed to be used in procedures that require the removal of specific contaminants.
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real-time assay (homogeneous/kinetic) simultaneous amplification of the target and detection of the product in which data collection occurs throughout the process Project: MM06
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real-time continuous glucose monitoring a continuous glucose monitoring system that displays glucose values that are concurrent with the user’s blood glucose Project: POCT05
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real-time polymerase chain reaction method that combines polymerase chain reaction and fluorescent probe detection of amplified product in the same reaction vessel Alternate Term: homogeneous, kinetic polymerase chain reaction Project: MM03, M55, MM24 NOTE: The presence of amplified product is determined with each polymerase chain reaction cycle.
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real-time polymerase chain reaction see polymerase chain reaction Project: NBS06
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real-time stability testing exposing the product to the recommended normal storage and in-use conditions and assessing its robustness and stability under those conditions Project: EP25
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real-world data data relating to patient health status or the delivery of health care routinely collected from a variety of sources Project: AUTO17
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real-world evidence generally, the evidence derived from real-world data (RWD) through application of appropriate study designs and analytical methods. More specifically in the regulatory context, the US Food and Drug Administration defines real-world evidence as “clinical evidence regarding the usage, and potential benefits or risks, of a medical product derived from analysis of RWD.” Project: AUTO17
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reasonably foreseeable misuse use of a medical device in a way not intended by the manufacturer, but which may result from readily predictable human behaviour Project: ISO CD 18113-1, ISO CD 18113-2, ISO CD 18113-3
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recall actions taken by a firm to remove a product from the market NOTE: Recalls are actions taken by manufacturers, distributors, importers, or regulatory agencies to carry out their responsibility to protect the public health.
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recall rate the percentage of tested newborns for whom additional action is requested (eg, requested repeat screening or clinical evaluation) to complete the screening process Project: NBS10 Source: Newborn Screening Glossary NOTE 1: Additional action might be needed because the initial specimen was unacceptable, screen inconclusive, and/or screen positive; NOTE 2: Recall rate = (a + b) / (a + b + c + d); see table in screening outcome; NOTE 3: Repeat screens that are collected as a part of routine screening practices (eg, routine second screens, serial screening protocols for preterm, low birth weight, or sick newborns) do not factor in to the recall rate calculation.
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recall termination (recall complete) FDA communication that a recall is complete Project: HS11 NOTE: This is not considered an Alert.
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recalls a method of removing or correcting products that are in violation of laws administered by a regulatory authority and that may represent a health hazard to the consumer or user Project: HS11 NOTE 1: Recalls are actions taken by manufacturers, distributors, importers, or regulatory agencies to carry out their responsibility to protect the public health; NOTE 2: Recalls may be classified into numerical categories (ie, I, II, or III, as described below) by regulatory agencies (eg, U.S. Food and Drug Administration, Health Canada, Australian Therapeutic Goods Agency) to indicate the relative degree of health hazard presented by the product being recalled. The FDA employs the following three-tiered classification system:Class I a situation in which there is a reasonable probability that the use of, or exposure to, a violative product will cause serious adverse health consequences or death. Class II a situation in which use of, or exposure to, a violative product may cause temporary or medically reversible adverse health consequences or where the probability of serious adverse health consequences is remote. Class III a situation in which use of, or exposure to, a violative product is not likely to cause adverse health consequences.
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recap to replace the closure on a specimen container, either with the original closure or with a new replacement closure Project: AUTO01, AUTO02
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recapper equipment to place caps back on specimens as part of an automation line
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receiver the device that responds to the sender and accepts the message Project: LIS01
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receiver operating characteristic curve (ROC curve) a graphical description of test performance that represents the relationship between the true-positive ratio and either the false-positive ratio or the true-negative ratio NOTE: Customarily, the true-positive ratio is plotted on the horizontal axis.
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receiver operating characteristic curve a graphical description of test performance representing the relationship between the true-positive fraction (sensitivity) and the false-positive fraction (1 − specificity) Project: EP24 NOTE: Alternate terms are “ROC plot,” “receiver operator characteristic curve,” “receiver operating characteristic plot,” and “receiver operator characteristic plot.”
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receiver operating characteristic plot a graphical description of test performance representing the relationship between the true-positive fraction (sensitivity) and the false-positive fraction (1-specificity) Alternate Term: ROC plot Project: I/LA21 NOTE 1: Customarily, the true-positive fraction is plotted on the vertical axis and the false-positive rate (or, alternatively, the true-negative fraction) is plotted on the horizontal axis; NOTE 2: Clinical accuracy, in terms of sensitivity and specificity, is displayed for the entire spectrum of decision levels.
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recency (recent HIV infection) the phase of infection from the time of confirmed detection of HIV antibodies until complete maturation of an antibody response as determined by a specific assay Project: M53 NOTE: The length of this interval is usually six to 12 months after seroconversion and is generally used to determine incidence in populations.
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recent isolate isolate recovered from a clinical sample within the previous twelve months(ISO 20776-2) Project: ISO 20776-2
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receptor as used in this document in reference to solid phase ligand binding assays, the molecular species of the solid phase (eg, cell or microsphere) to which the corresponding fluorochrome-labeled ligand shows saturable binding Project: I/LA24
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receptor any of various specific protein molecules in surface membranes of cells and organelles to which complementary molecules, such as hormones, neurotransmitters, antigens, or antibodies, may become bound Project: LA01
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recessive autosomal recessive describes a trait or disorder requiring the presence of two copies of a gene mutation at a particular locus in order to express observable phenotype; specifically refers to genes on one of the 22 pairs of autosomes (nonsex chromosomes). X-linked (sex-linked) recessive refers to a mode of inheritance in which a mutation in a gene on the X chromosome causes the phenotype to be expressed in males who are hemizygous for the gene mutation (ie, males with only one X chromosome) and in females who are homozygous for the gene mutation (ie, females with a copy of the gene mutation on each of their two X chromosomes). Carrier females who have only one copy of the mutation do not usually express the phenotype, although differences in X-chromosome inactivation can lead to varying degrees of clinical expression in carrier females
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recipient reagent a reagent that has the potential to be affected by carryover from a source reagent Project: EP47 NOTE: Residual material from a source reagent can be transferred into a recipient reagent or a reaction cell.
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re-collection (for newborn screening) collection of another dried blood spot specimen from the same patient, owing to an unacceptable initial specimen or an out-of-range initial screening test result Project: NBS01, NBS13, NBS09, NBS10 Source: Newborn Screening Glossary NOTE 1: Some newborn screening programs are mandated to collect second and third specimens from all newborns, which is different from re-collection; NOTE 2: Many newborn screening programs collect second and third specimens from preterm, low birth weight, or sick newborns because of the high risk of an initial false-negative result in this population; NOTE 3: See repeat screening (requested).
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recombinant allergen molecule an allergenic molecule is produced in a heterologous cell system using a recombinant gene construct encoding the allergenic protein Project: I/LA20 NOTE: A description of the process of cloning, sequencing, transfecting expression vectors, and expressing allergenic peptides and proteins is beyond the scope of I/LA20. Some immunoglobulin E antibody assays currently use recombinant allergens to supplement natural allergen extracts and replace labile, low abundance, or absent allergens (eg, rHev b 5 in the Hevea brasiliensis latex–containing reagent).
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recombinant allergens allergenic molecules produced in a heterologous cell system using a recombinant gene construct encoding the allergenic protein Project: I/LA34 NOTE: A description of the process of cloning, sequencing, transfecting expression vectors, and expressing allergenic peptides and proteins is beyond the scope of this document. Some immunoglobulin E antibody assays currently use some recombinant allergens to supplement natural allergen extracts and replace labile, low abundance, or absent allergens (eg, rHev b 5 in the Hevea brasiliensis latex containing reagent).
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recombinant derived antigen peptides or proteins produced by the introduction of genetic material into cells of another genus, species, or class of organism. See also Immunogen
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recombinant DNA DNA that has been altered by joining genetic material from two different sources
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recommendation for the purposes of QMS17, refers to comments or suggestions made by the assessment organization for improved practice, to which the laboratory is not required to respond or implement Project: QMS17 NOTE: Some organizations refer to recommendations as “opportunities for improvement.”
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recommended dilution the dilution ratio tested that produces results that meet dilution recovery performance needs Project: EP34 NOTE: The analytical measuring interval and the recommended dilution define the extended measuring interval.
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recommended selected method See working method Project: H02
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reconstitute to add a specified liquid diluent to a dried calibrator, control, or reagent, to make its concentration as it was before drying Project: POL1/2
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record (noun) evidence of results achieved or activities performed (modified from ISO 9000) Project: QMS02, QMS01, QMS06, QMS17, GP26, QMS16, QMS26, QMS03 Source: Quality Glossary EXAMPLES: Proficiency testing results, completed temperature charts, completed forms; NOTE 1: Records can be used, for example, to demonstrate traceability and to provide evidence of verification or corrective action (modified from ISO 9000); NOTE 2: Generally, records need not be under revision control (ISO 9000).
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record (verb) the action of documenting in a recoverable medium the activities performed or results achieved Project: QMS02, QMS01, QMS26 Source: Quality Glossary
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record an aggregate of fields describing one aspect of the complete message Project: LIS02
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recording device part of a measuring instrument that provides record of an indication
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recording instrument (measuring) measuring instrument that provides a record of the indication; EXAMPLES: a) barograph; b) thermoluminescent dosimeter; c) recording spectrometer NOTE 1: The record (display) may be analogue (continuous or discontinuous line) or digital; NOTE 2: Values of more than one quantity may be recorded (displayed) simultaneously; NOTE 3: A recording instrument may also display an indication. (VIM93)
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records management field of management responsible for the efficient and systematic control of the creation, receipt, maintenance, use, and disposition of records, including processes for capturing and maintaining evidence of and information about business activities and transactions in the form of records (ISO 15489) Project: QMS26
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records management system a system that manages both paper and electronic records to ensure that all laboratory records are created, identified, changed, reviewed, retained, stored, and maintained in a matter that meets requirements Project: QMS26
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recovery the measurable increase in analyte concentration in a sample after adding a known amount of an identical substance Project: LA01, I/LA34, I/LA20 NOTE: Unspiked and spiked serum specimens are analyzed in the assay, and the proportion of the analyte that is detected over preexisting analyte levels is compared to the amount added. Accuracy in identifying the amount of analyte added is essential to a recovery study. A recovery of 100% is considered ideal. An alternative form of recovery studies is called dilution-recovery analysis.
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recovery (spiking) a ratio of the measured increase in a sample’s analyte concentration to the known amount of analyte added Project: EP34 NOTE: Unspiked and spiked samples are measured, and the proportion of the analyte that is measured over preexisting analyte levels in unspiked specimens is compared to the amount added. Accuracy in identifying the amount of analyte added is essential to a recovery study. A recovery of 100% is considered ideal.
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recovery in the context of GP36, refers to either recovery of a critical business or laboratory function during the incident response phase; or alternatively, to postincident efforts intended to produce a global return to normalcy Project: GP36 NOTE: Latter efforts should address both the nonhuman and human effects of disaster.
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recovery the restoration, and improvement when appropriate, of facilities, livelihoods, and living conditions of emergency- or disaster-affected communities, including efforts to reduce emergency or disaster risk factors Project: POCT16
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recovery (dilution) a ratio of the computed value of a measurand in a diluted sample to the value of the measurand in the specimen before its dilution; 100% is considered ideal Project: EP34 NOTE 1: The computed measurand value of the diluted sample incorporates the measured value of the measurand and the level of dilution; NOTE 2: Recovery is a measure of trueness only when the value of the measurand in the undiluted specimen is assigned by a reference method or created from reference material rather than measured by the candidate measurement procedure.
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recreational substance any substance that may be abused or used for nontherapeutic purposes regardless of legal status Alternate Term: recreational drug Project: C52
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recumbent lying down or reclining backward Project: PRE02
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reduced media media that has been placed in an anaerobic environment for a period of time before inoculation with bacterial isolates Project: M11 NOTE 1: This term replaces “prereduction”; NOTE 2: The period of time need for reduction is based on the volume of the media being used (eg, larger volumes of broth need longer reduction times).
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reducing agent a chemical used in formulating anaerobe media to balance the oxidation-reduction level of the medium to a reduced state (ie, contains compounds with an excess of electrons) Project: M56 NOTE: This balance is metabolically important for energy production and growth of anaerobes.
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redundancy the duplication of critical components of a system with the intention of increasing reliability, usually in the case of a backup or fail-safe system Project: GP36
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referee laboratory a laboratory currently in compliance with applicable CLIA requirements; that has had a record of satisfactory proficiency testing performance for all testing events for at least one year for a specific test, analyte, subspecialty, or specialty; and has been designated by an HHS-approved- proficiency-testing program as a referee laboratory for analyzing proficiency testing specimens, for the purpose of determining the correct response for the specimens in a testing event for that specific test, analyte, subspecialty, or specialty (US CFR493 February 28, 1992)
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referee laboratory a laboratory selected for the purpose of determining the correct response for the samples in a testing event for that specific test or measurand Project: MM14 NOTE: In the United States, a laboratory currently in compliance with applicable Clinical Laboratory Improvement Amendments requirements that has had a record of satisfactory proficiency testing performance for all testing events for at least one year for a specific test, measurand, subspecialty, or specialty; and has been designated by a US Department of Health and Human Services–approved proficiency testing program as a referee laboratory for analyzing proficiency testing samples, for the purpose of determining the correct response for the samples in a testing event for that specific test, measurand, subspecialty, or specialty.
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reference a type of measurement or type of device for making a measurement that a continuous glucose monitoring method can be compared with Project: POCT05 NOTE: The term “reference method” is often used synonymously with a comparison method or a comparator.
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reference change value represents the statistically significant difference between consecutive results based on the combined inherent variation of both results. The total variation of a result is a combination of preexamination, examination, postexamination, and within-subject biological variation Project: EP33
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reference conditions conditions of use prescribed for testing the performance of a measuring instrument or for intercomparison of results of measurements NOTE The reference conditions generally include reference values or reference ranges for the influence quantities affecting the measuring instrument.
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reference curve a line, typically a straight line, that defines the quantitative relationship between an independent variable and a dependent variable Project: H30 NOTE: From this line the observed output of an analytic procedure (eg, activated partial thromboplastin time test) can be converted to the units of measurement of the analyte of interest (eg, coagulation factor activity).
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reference cutoff a value from a given reference distribution that represents a clinical decision point (eg, below the 10th percentile or above the 95th percentile)
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reference data data related to a property of a phenomenon, body, or substance, or to a system of components of known composition or structure, obtained from anidentified source, critically evaluated, and verified for accuracy (JCGM 200:2008) Project: ISO IEC Guide 99 EXAMPLE: Reference data for solubility of chemical compounds as published by the IUPAC (JCGM 200:2012); NOTE 1: In this definition, accuracy covers, for example, measurement accuracy and ‘accuracy of a nominal property value’ (JCGM 200:2012); NOTE 2: "Data" is a plural form, "datum" is the singular. "Data" is commonly used in the singular sense, instead of "datum" (JCGM 200:2012).
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reference distribution a quantitative description of the dispersion of measurements of a given characteristic of a stated and defined population Project: DI01
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reference distribution the distribution of reference values Project: EP28 NOTE: Hypotheses regarding the distribution of a reference population can be tested using the reference distribution of the reference sample group and adequate statistical methods. The parameters of the hypothetical distribution of the reference population can be estimated using the reference distribution of the reference sample group and adequate statistical methods.
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reference distribution the distribution of reference values Project: EP45
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reference document for purposes of QMS17, any document (eg, book, checklist, regulation, standard) that specifies requirements Project: QMS17 NOTE: Reference documents can contain suggestions on how to successfully fulfill the requirements as well as mandatory items required by the organization as proof of compliance.
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reference half-cell one-half of an overall electrochemical cell whose potential is fixed and independent of the activity of any species in solution Project: C39
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reference individual a person selected for testing based on well-defined criteria Project: EP28, EP45 NOTE: It is usually important to define the person’s state of health. The following terms are used in connection with selecting reference individuals in the context of this CLSI document:
a priori – application of criteria before the collection of samples
a posteriori – application of criteria after the collection of samples
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reference interval the range of values obtained on specimens from normal controls assayed under the conditions used for patient specimens Project: H42, H43 NOTE: Assayed values that fall outside the reference interval are considered abnormal and may indicate a disease state. Relevant reference intervals are dependent on the assay methodology employed and on the composition of the patient population studied (eg, with respect to age and sex).
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reference interval the interval between, and including, two reference limits Project: C50, POCT09 NOTE 1: It is designated as the interval of values from the lower reference limit to the upper reference limit (eg, for fasting glucose the reference interval is 65 to 110 mg/dL [3.6 to 6.1 mmol/L]; and for calcium, the reference interval is 9.1 to 10.3 mg/dL [2.27 to 2.57 mmol/L]); in some cases, only one reference limit is important, usually an upper limit, “x,” and the corresponding reference interval would be 0 to x); NOTE 2: The following terms are used in connection with reference intervals in the context of this document:
- defining a reference interval - describing in detail the characteristics of the reference interval (ie, the central 95% of apparently healthy men and women between the ages of 18 and 65).
- establishing (or determining) a reference interval - the process used in creating a reference interval de novo, encompassing all of the steps from selection of reference individuals, through exact details of the analytical methods, and concluding with data collection and analysis.
- transferring a reference interval - the process that adapts a previously established reference interval to a new analytical method or to a new location.
- verifying (or validating) a reference interval - the process that ensures, with reasonable confidence, using a relatively small number of reference individuals (eg, n = 20), that a reference interval established elsewhere, or transferred from another study, can be used locally.
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reference interval 1) interval between, and including, the lower reference limit to the upper reference limit of the reference population (eg, 95% of persons presumed to be healthy [or normal]); 2) the range of test values expected for a designated population of individuals Alternate Term: reference range Project: C48, POCT04, H58, H26, H59 NOTE 1: For example, the reference interval for fasting glucose measurement in plasma is 3.6 to 6.1 mmol/L; NOTE 2: In some cases, only one reference limit is important, usually an upper limit, “x,” and the corresponding reference interval would be 0 to x; NOTE 3: For nucleic acid sequence analysis, the reference interval refers to the types of sequence variations that can occur at a base position or region of the genome in a reference population. For example, these may include base substitutions, insertions/deletions of a certain size range, or other defined structural variations.
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reference interval interval between and including the lower reference limit to the upper reference limit of the reference population (eg, 95% of individuals presumed to be healthy [or normal]) Project: MM22, MM24 NOTE: See reference range.
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reference interval specified interval of the distribution of values taken from a biological reference population (ISO 18113-1, ISO 15189) Project: MM21, H48 NOTE 1: Interval between, and including, the lower reference limit to the upper reference limit of the reference population (eg, 95% of persons presumed to be healthy [or normal]); NOTE 2: For genomic copy number microarrays, the range of copy number variants and absence of heterozygosity that occur in the normal healthy population. Also see reference range; NOTE 3: For example, the reference interval for fasting glucose measurement in plasma is 3.6 to 6.1 mmol/L.
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reference interval interval between, and including, the lower reference limit to the upper reference limit of the reference population (eg, 95% of persons presumed to be healthy [or without the conditions or disease states that cause decreased or increased amounts of measurand]) Project: EP19, MM01, EP45
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reference interval the range of values obtained on specimens from normal donors assayed under the conditions used for patient specimens
Project: H62 NOTE: Assayed values that fall outside the reference interval are considered abnormal and may indicate a disease state. Relevant reference intervals depend on the assay methodology used and the composition of the patient population studied (eg, with respect to age and sex).
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reference interval interval between, and including, the lower reference limit (eg, − 2 standard deviations) to the upper reference limit (eg, + 2 standard deviations) of the reference population Project: H60 EXAMPLE: The reference interval for prothrombin time is 11 to 15 seconds.
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reference interval the range of values obtained on specimens from normal controls assayed under the conditions used for patient or testing specimens Project: H52 NOTE: Assayed values that fall outside the reference interval are considered abnormal and may indicate a disease state. Relevant reference intervals are dependent on the assay methodology employed and on the composition of the patient population studied (eg, with respect to age and sex).
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reference interval See reference range Alternate Term: reference range; normal range Project: VET04
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reference laboratory 1) In the United States, a Medicare-enrolled laboratory that receives a specimen from another referring laboratory for testing, and performs the test (see Medicare Claims Processing Manual); 2) In other countries, usually a laboratory that has the capability of providing certain testing or examination services Project: MM20
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reference limit 1) the lowest or highest value defining the reference distribution and used for descriptive purposes; 2) a value derived from the reference distribution and used for descriptive purposes Project: EP28, EP45 NOTE: It is common practice to define a reference limit so that a stated fraction of the reference values is less than or equal to, or greater than or equal to, the respective upper or lower limit; the reference limit is descriptive of the reference values and can be distinguished from various other types of decision limits.
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reference material material, sufficiently homogeneous and stable with reference to specified properties, which has been established to be fit for its intended use in measurement or in examination of nominal properties (JCGM 200:2012) Project: ISO IEC Guide 99, ISO 18113-1, MM06, MM19, C40, MM22, MM09, H48, EP30, MM24, EP12 EXAMPLE 1: Examples of reference materials embodying quantities: a) water of stated purity, the dynamic viscosity of which is used to calibrate viscometers; b) human serum without an assigned quantity value for the amount-of-substance concentration of the inherent cholesterol, used only as a measurement precision control material; c) fish tissue containing a stated mass fraction of a dioxin, used as a calibrator (JCGM 200:2012); EXAMPLE 2: Examples of reference materials embodying nominal properties: a) color chart indicating one or more specified colors; b) DNA compound containing a specified nucleotide sequence; c) urine containing 19-androstenedione (JCGM 200:2012); EXAMPLE 3: Substance of known triple-point in a triple-point cell; EXAMPLE 4: Glass of known optical density in a transmission filter holder; EXAMPLE 5: Spheres of uniform size mounted on a microscope slide (JCGM 200:2012); NOTE 1: Examination of a nominal property provides a nominal property value and associated uncertainty. This uncertainty is not a measurement uncertainty (JCGM 200:2012); NOTE 2: Reference materials with or without assigned quantity values can be used for measurement precision control, whereas only reference materials with assigned quantity values can be used for calibration or measurement trueness control (JCGM 200:2012); NOTE 3: “Reference material” comprises materials embodying quantities, as well as nominal properties (JCGM 200:2012); NOTE 4: A reference material is sometimes incorporated into a specially fabricated device; NOTE 5: Some reference materials have assigned quantity values that are metrologically traceable to a measurement unit outside a system of units. Such materials include vaccines to which International Units have been assigned by the World Health Organization (JCGM 200:2012); NOTE 6: In a given measurement, a given reference material can only be used for either calibration or quality assurance (JCGM 200:2012); NOTE 7: The specifications of a reference material should include its material traceability, indicating its origin and processing (Accred Qual Assur. 2006;10:576-578); NOTE 8: Reference material is a material or substance, one or more of whose property values are sufficiently homogeneous and well established to be used for the calibration of a measuring system, the assessment of a measurement procedure, or for assigning values to materials (JCGM 200:2008); NOTE 9: Reference material is a generic term (ISO Guide 31); NOTE 10: Properties can be quantitative or qualitative, eg, identity of substances or species (ISO Guide 31); NOTE 11: Uses may include the calibration of a measurement system, assessment of a measurement procedure, assigning values to other materials, and quality control (ISO Guide 31); NOTE 12: A reference material can only be used for a single purpose in a given measurement; NOTE 13: CLSI EP30 does not apply to examination of nominal properties.
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reference material material, sufficiently homogeneous and stable regarding one or more properties, used in calibration, assignment of a value to another material, or quality assurance (ISO 15194) Project: ISO 15194 NOTE 1: “Reference material” comprises materials embodying quantities as well as nominal properties (ISO 15194); EXAMPLE 1: Human serum with an assigned quantity value for the amount-of-substance concentration of cholesterol, used only as a calibrator, embodies a quantity (ISO 15194); EXAMPLE 2: DNA compound containing a specified nucleic acid sequence embodies a nominal property (ISO 15194); NOTE 2: In this definition, value covers both “quantity value” and “nominal property value” (ISO 15194); NOTE 3: Some reference materials have quantities which are metrologically traceable to a measurement unit outside a system of units. Such materials include those containing antibodies to which International Units have been assigned by the World Health Organization (ISO 15194); NOTE 4: A reference material is sometimes incorporated into a specially fabricated device, eg, glass of known optical density in a transmission filter holder, spheres of uniform particle size mounted on a microscope slide, and calibration plate for microtiter plate reader (ISO 15194).
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reference material material or substance, one or more of whose property values are sufficiently homogeneous and well established to be used for the calibration of a measuring system, the assessment of a measurement procedure, or for assigning values to materials Project: ISO 15195, MM17, C64 NOTE 1: Reference material is a generic term (ISO Guide 31, ISO 17034); NOTE 2: Properties can be quantitative or qualitative, eg, identity of substances or species (ISO Guide 31, ISO 17034); NOTE 3: Uses may include the calibration of a measurement system, assessment of a measurement procedure, assigning values to other materials, and quality control (ISO Guide 31, ISO 17034); NOTE 4: A reference material can only be used for a single purpose in a given measurement.
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reference material material or substance, one or more of whose property values are sufficiently homogeneous and well established to be used for the calibration of an apparatus, the assessment of a measurement method, or for assigning values to materials (modified from ISO 15195) Project: ISO 15195, C37, MM12, ISO CD 18113-1, ISO CD 18113-2, ISO CD 18113-3 NOTE 1: A reference material may be in the form of a pure or mixed gas, liquid or solid. Examples are water for the calibration of viscometers, sapphire as a heat-capacity calibrant in calorimetry, and solutions used for calibration in chemical analysis (ISO Guide 30:1992); NOTE 2: The adjective “homogeneous” refers to the physical homogeneity between macroscopic parts of the material, not to any microheterogeneity between molecules of the analyte (ISO 17511); NOTE 3: A given reference material may be used either as a calibration material in calibration of a measuring system and in assigning values to materials, or as a control material in assessing the performance of a measurement procedure, but must not be used for both purposes in a given situation in a particular laboratory.
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reference material material, sufficiently homogeneous and stable regarding one or more properties, with reference to specified properties, which has been established to be fit for its intended use in measurement or in examination of nominal properties (ISO 18113) Project: EP17, H62 NOTE 1: Reference materials with or without assigned quantity values can be used for measurement precision control, whereas only reference materials with assigned quantity values can be used for calibration or measurement trueness control; NOTE 2: With assigned value, can be used for calibration or to establish accuracy during validation; NOTE 3: Without assigned value, can be used for measurement to establish precision during validation or as an assay quality control; NOTE 4: See standard reference material.
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reference measurement laboratory laboratory that performs a reference measurement procedure and provides results with stated uncertainties Project: EP32 NOTE: ISO 17511 also uses the terms “reference laboratory” and “calibration laboratory.” All three terms are synonymous, and different publications might use these terms to refer to the same type of laboratory.
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reference measurement procedure measurement procedure accepted as providing measurement results fit for their intended use in assessing measurement trueness of measured quantity values obtained from other measurement procedures for quantities of the same kind, in calibration, or in characterizing reference materials (JCGM 200:2012) Project: ISO IEC Guide 99, POCT05, MM06, H02, EP21, QMS24, C64, EP12 NOTE 1: The roles of reference measurement procedures are detailed in ISO 17511 and ISO 18153; NOTE 2: In ISO terminology, trueness is related to bias, systematic effect, and systematic error, whereas “accuracy” is related to both trueness (with its relations) and precision, which itself is related to standard deviation, random effect, and random error (ISO 15193); NOTE 3: The term “reference measurement procedure” is intended to be understood as a measurement procedure of higher order; NOTE 4: Requirements for reference measurement procedures for in vitro diagnostic medical devices are described in ISO 15193; NOTE 5: Examples of the use of reference measurement procedures to assign values to in vitro diagnostic calibrators are given in ISO 17511 and ISO 18153; NOTE 6: A reference measurement procedure used to obtain a measurement result without relation to a measurement standard for a quantity of the same kind is called a “primary reference measurement procedure” (JCGM 200:2012); NOTE 7: Thoroughly investigated measurement procedure shown to yield values having an uncertainty of measurement commensurate with its intended use, especially in assessing the trueness of other measurement procedures for the same quantity and in characterizing reference materials; NOTE 8: Formerly, the term “reference method” was used in CLSI documents.
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reference measurement procedure thoroughly investigated measurement procedure shown to have an uncertainty of measurement commensurate with the intended use, especially in assessing the trueness of other measurement procedures for the same quantity and in characterizing reference materials Project: EP30 NOTE 1: When several reference measurement procedures exist for a given measurable quantity, it may be possible to arrange them in a hierarchy according to size of uncertainty of measurement. A primary reference measurement procedure is sometimes termed a “definitive method of measurement,” but not by VIM:1993; NOTE 2: The Consultative Committee on Amount of Substance (CCQM) of BIPM has defined a “primary method of measurement” as a method having the highest metrological qualities, whose operation can be completely described and understood, for which a complete uncertainty statement can be written down in terms of SI units, and whose results are, therefore, accepted without reference to a standard of the quantity being measured. For amount of substance, the following principles of measurement were identified as suitable for primary measurement procedures: isotope dilution – mass spectrometry, coulometry, gravimetry, titrimetry, and determination of colligative properties such as freezing point depression (BIPM, Comité Consultatif pour La Quantite de Matiere, 1995); NOTE 3: The Analytical Chemistry Division of IUPAC describes an allied concept, “absolute method,” wherein calculations are based on universal quantities and fundamental physical constants only; NOTE 4: Reference measurement procedures for SI-traceable measurands are based on matrix-independent measurement principles and are directly calibrated with gravimetrically prepared primary calibrator material; NOTE 5: With respect to measurands that are not (yet) SI-traceable, the term “international conventional reference measurement procedure” applies.
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reference measurement procedure thoroughly investigated measurement procedure shown to yield values having an uncertainty of measurement commensurate with its intended use, especially in assessing the trueness of other measurement procedures for the same quantity and in characterizing reference materials Project: ISO 15193, ISO 17511, EP11, C45 NOTE 1: Reference measurement procedures for SI-traceable measurands are based on matrix-independent measurement principles and are directly calibrated with gravimetrically prepared primary calibrator material; NOTE 2: With respect to measurands that are not (yet) SI-traceable, the term “international conventional reference measurement procedure” applies.
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reference measurement procedure measurement procedure accepted as providing measurement results fit for their intended use in assessing measurement trueness of measured quantity values obtained from another measurement procedure for a quantity of the same kind, in calibration, or in assigning a quantity value to a certified reference material (modified from ISO 15193) Project: EP32
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reference measurement procedure an analytical measurement procedure sufficiently free of random or systematic error to make it suitable for validating proposed new analytical procedures for the same measurand Project: EP27
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reference measurement standard measurement standard designated for the calibration of other measurement standards for quantities of a given kind in a given organization or at a given location (JCGM 200:2008) Alternate Term: reference standard Project: ISO IEC Guide 99
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reference method a clearly and exactly described technique for a particular determination that, in the opinion of a defined authority, provides sufficiently accurate and precise laboratory data for it to be used to assess the validity of other laboratory methods for this determination. The accuracy of the reference method must be established by comparison with a definitive method when one exists, and the degree of inaccuracy and imprecision must be stated Project: H15, POCT05 NOTE: The term “reference method” is often used synonymously with a comparison method or a comparator.
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reference method for ISO 20776-2, reference method described in ISO 20776-1 Project: ISO 20776-2
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reference method a thoroughly investigated method, in which exact and clear descriptions of the necessary conditions and procedures are given for the accurate determination of one or more property values, and in which the documented trueness and precision of the method are commensurate with the method’s use for assessing the trueness of other methods for measuring the same property values or for assigning reference method values to reference materials Project: C44, H44, NRSCL13, EN 12286, ISO 15193, MM10, MM12, H20, MM22, M02, M07 NOTE 1: This definition is analogous to a reference measurement procedure in ISO terminology. According to ISO a reference measurement procedure is a thoroughly investigated measurement procedure shown to have an uncertainty of measurement commensurate with the intended use, especially in assessing the trueness of other measurement procedures for the same quantity and in characterizing reference materials (adopted from ISO/DIS 15193, EN 12286); NOTE 2: This is the second-highest ranking method in the NRSCL hierarchy; NOTE 3: Several categories of reference method exist, including: Class A reference method, which is characterized by both sufficient accuracy and precision and by a low incidence of susceptibility to known interferences, so that the stated purpose of the analytical process can be achieved, all of which is demonstrated by direct comparison with the definitive method; Class B reference method, which is believed to be of the caliber of a Class A Reference Method, except that the process of evaluation with a definitive method and a certified reference material has not yet been completed; Class C reference method, which is believed to be of the caliber of a Class A Reference Method, except that no definitive method is likely to become available. See also Definitive method and Designated comparison method; NOTE 4: The following definition pertains to the context of CLSI standard H20 only: a carefully controlled set of specified procedures including sample preparation, staining, classification, and tabulation of each sample. It is a statistically devised protocol aimed at optimizing the chance of a proper determination of truth. All white blood cells are classified sequentially by a qualified examiner with special skills in morphologic hematology; therefore, interaction of the measurands is a component of the reference method. Although the reference method is considered true, it may still be imprecise. This imprecision can be reduced by carrying out the procedure in duplicate and averaging the results.
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reference method an exactly defined technique that is used in association with an internationally agreed reference preparation to provide sufficiently precise and accurate data for assessing the validity of other methods (modified from ICSH) Alternate Term: reference procedure Project: H02
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reference method a thoroughly investigated method in which exact and clear descriptions of the necessary conditions and procedures are given for the accurate determination of one or more property values, and in which the documented accuracy and precision of the method are commensurate with the method’s use for assessing the accuracy of other methods for measuring the same property values or for assigning reference method values to reference materials Project: M52, MM24 NOTE: Comparator methods may include reference methods, referral laboratory results, or a previously verified method.
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reference method the method to the standard to which a test method is compared
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reference method a methodology that has exact and clear descriptions of the necessary conditions and procedures that provide sufficiently accurate and precise laboratory data for it to be used to assess the validity of other laboratory methods Project: MM19
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reference operating condition operating condition prescribed for evaluating the performance of a measuring instrument or measuring system or for comparison of measurement results (JCGM 200:2012) Alternate Term: reference condition Project: ISO IEC Guide 99 NOTE 1: Reference operating conditions specify intervals of values of the measurand and of the influence quantities (JCGM 200:2012); NOTE 2: In IEC 60050-300, item 311-06-02, the term "reference condition" refers to an operating condition under which the specified instrumental measurement uncertainty is the smallest possible (JCGM 200:2012).
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reference person a person who is selected for testing on the basis of well-defined criteria (eg, age, gender, state of health and/or disease)
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reference plasma a citrated, normal, pooled plasma with known von Willebrand factor antigen or ristocetin cofactor activity prepared in-house or commercially available Project: H51 NOTE: This plasma is used to construct the reference curve.
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reference plasma citrated normal pooled plasma of known coagulant factor activity prepared in-house or available from a manufacturer Project: H30 NOTE: This plasma is used to construct the reference curve.
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reference population a group consisting of all the reference individuals Project: EP28, EP45 NOTE 1: The reference population usually has an unknown number of members and, therefore, is a hypothetical entity; the reference population might consist of only one member (eg, a person can serve as a reference for themself, or for another person); NOTE 2: These “subject-specific” reference intervals are not addressed in this guideline.
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reference population a group of n persons in a described state of health or disease Project: C57
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reference procedure See reference method Project: H02
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reference quantity value quantity value used as a basis for comparison with values of quantities of the same kind (JCGM 200:2012) Alternate Term: reference value Project: ISO IEC Guide 99, C24 NOTE 1: A reference quantity value can be a true quantity value of a measurand, in which case it is unknown, or a conventional quantity value, in which case it is known (JCGM 200:2012); NOTE 2: A reference quantity value with associated measurement uncertainty is usually provided with reference to: a) a material, eg, a certified reference material; b) a device, eg, a stabilized laser; c) a reference measurement procedure; d) a comparison of measurement standards (JCGM 200:2012); NOTE 3: An “accepted reference value” is a value that serves as an agreed-upon reference for comparison, and which is derived as a theoretical or established value, based on scientific principles; an assigned or certified value, based on experimental work of some national or international organization; or a consensus or certified value, based on collaborative experimental work under the auspices of a scientific or engineering group.
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reference range the range of test values expected for a designated population of individuals (42 CFR 493) Alternate Term: reference interval; normal range Project: VET03, VET04, MM21 EXAMPLE: Ninety-five percent of individuals that are presumed to be healthy (or normal) (42 CFR 493.210); NOTE: For genomic microarrays, includes criteria to identify and to report a copy number variant as potentially deleterious. Also see reference interval.
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reference sample group an adequate number of persons selected to represent the reference population Project: EP28, EP45
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reference sequence sequence of a gene segment known to represent a stable, invariant presence or copy number within a sample Project: NBS06 NOTE: The T-cell receptor excision circle assays in current use for severe combined immunodeficiency newborn screening use a sequence from either the gene coding for ribonuclease P or the gene coding for beta-actin. Detection of the presence of this reference sequence indicates that the DNA obtained from the sample is amplifiable and quantitation of this sequence indicates the relative number of human cells in the sample.
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reference standard the best available method for establishing the presence or absence of the condition or characteristic of interest Project: MM17, MM09 NOTE 1: The reference standard can be a single test or method, or a combination of methods and techniques, including clinical follow-up (from Standards for Reporting of Diagnostic Accuracy); NOTE 2: The reference standard (as defined by Standards for Reporting of Diagnostic Accuracy) will evolve with the advancement of analytical systems, and may in a given situation be different from a reference standard so determined by a regulatory or metrology agency; NOTE 3: A reference standard divides the intended use population into only two groups, and does not consider the outcome of the candidate test (new test under evaluation). A reference standard can be a combination of methods where the standard is the algorithm specifying the choice and ordering of these methods, and how the different results are combined to make a final positive/negative classification; NOTE 4: The VIM93 definition for reference is different, and is defined as a standard, generally having the highest metrological quality available at a given location or in a given organization from which measurements made there are derived.
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reference strain catalogued, characterized bacteria with stable, defined antimicrobial susceptibility phenotypes and/or genotypes (ISO 20776-1) Project: ISO 20776-1 NOTE: Reference strains are kept as stock cultures, from which working cultures are derived. They are obtainable from culture collections and used for quality control (ISO 20776-1).
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reference strain a particular strain of a bacterial species that can be obtained from a microbiological repository, such as the American Type Culture Collection, which exhibits stable genetic properties and yields reproducible minimal inhibitory concentrations when tested in vitro against designated antimicrobial agents Project: M43
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reference value the value (test result) obtained by the observation or measurement of a particular type of quantity on a reference individual Project: EP28, EP45 NOTE: Reference values are obtained from a reference sample group.
The following scheme demonstrates the relationship between the terms defined.
(1) REFERENCE INDIVIDUALS comprise a
(2) REFERENCE POPULATION from which is selected a
(3) REFERENCE SAMPLE GROUP on which are determined
(4) REFERENCE VALUES that characterize
(5) REFERENCE DISTRIBUTION from which are calculated
(6) REFERENCE LIMITS that may define
(7) REFERENCE INTERVALS
(8) OBSERVED VALUE in a person can be compared with (4) through (7).
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reference value (accepted) a value that serves as an agreed-upon reference for comparison and which is derived as: a theoretical or established value based on scientific principles; an assigned value based on experimental work of some national or international organization; or a consensus value based on collaborative experimental work under the auspices of a scientific or engineering group (ISO 5725-1) Project: I/LA23
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reference-anchored real-time study design a type of stability study design in which the on-test product is compared with a stability reference product stored under a known stable condition, minimizing the effects of long-term variation Project: EP25 EXAMPLE: An on test calibrator is evaluated against vials of the same calibrator stored at −70°C, at each time point
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referral laboratory external laboratory to which a sample is submitted for examination (ISO 15189) Project: ISO 15189, MM20, GP36, GP47
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referral laboratory external laboratory to which a sample is submitted for an examination procedure Alternate Term: reference laboratory Project: QMS05, M52 NOTE: Referral/reference laboratories can include laboratories that are considered internal because they are a subsidiary of the parent laboratory, but are truly external because they operate under a different quality management system.
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referring laboratory laboratory that submits samples for a supplementary or confirmatory examination procedure and receives the report from the referral laboratory Project: QMS05, GP36
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referring laboratory the laboratory that sends a specimen or asset to the performing laboratory for testing Project: AUTO14 NOTE: The referring laboratory may or may not have labeled a specimen or asset with a CLSI AUTO14 bar code
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reflectance r, radiant power reflected from the surfaces of a system in a specified direction NOTE: ,frefl, divided by incident radiant power,f0.
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reflected power the power that occurs when the traveling electromagnetic waves are reflected and the flow of energy is partly in the reverse direction Project: GP28 NOTE 1: Reflected microwave energy can result in overheating or a deficiency of microwave energy in localized areas; NOTE 2: Devices that remove reflected microwaves have been designed to protect the magnetron from microwave energy reflected back into the wave-guide.
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reflex test follow-up testing automatically initiated when certain test results are observed in the laboratory; used to clarify or elaborate on primary test results Project: AUTO15
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reflex testing follow-up testing automatically initiated when certain test results are observed in the laboratory; used to clarify or elaborate on primary test results Project: MM19, GP49
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refractometer an instrument used to measure the refractive index of a material NOTE: Specifically calibrated refractometers may be designed to evaluate the specific gravity (relative density) of a solution by measuring the total dissolved solids in a liquid, as indicated by the refractive index of the solution.
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refrigerate maintain at a thermostatically controlled temperature between 2 to 8°C Project: PRE04
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refrigerated storage system (automated) refrigeration unit for specimens attached to an automation line
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region a continuous part of a single or bivariate histogram that is using projections (cursors) that define one or more populations of interest in that histogram. When the cells of a specific region are imported into a subsequent histogram of one, two, or higher numbers of parameters, the imported region is referred to as a gate Project: I/LA26 NOTE: Flow cytometry data is expressed or visualized as single or bivariate (correlation of any two acquired parameters) histograms, though higher numbers of parameters can be visualized (three parameter “clouds”, or N-dimensional projections). Analysis of flow cytometry data is accomplished by the use of regions and gates.
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registration authority an optional public key infrastructure entity (separate from the certification authorities) that does not sign either digital certificates or certificate revocation lists but has responsibility for recording or verifying some or all of the information (particularly the identities of subjects) needed by a certification authority to issue certificates and certificate revocation lists and to perform other certificate management functions (RFC 2828) Project: AUTO09
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regression the process of estimating the parameters of a model by optimizing the value of an objective function and then testing the resulting predictions for statistical significance against an appropriate null hypothesis model. (ISO3534-3-3.3) Alternate Term: regression analysis Project: ISO 3534-3-3.3
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regression analysis the process of estimating the parameters of a model by optimizing the value of an objective function and then testing the resulting predictions for statistical significance against an appropriate null hypothesis model; the process of describing mathematically the relationship between two or more variables NOTE: This can include the parametric testing of the statistical significance of the relationship, if random errors are assumed to be normal.
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regression multiplier factors derived from the experimental design and used (in Data Summary Sheet #4 of CLSI EP10) to multiply the observed data Project: EP10
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regulated medical waste as referenced in Department of Transportation regulations, a waste or reusable material, other than a culture or stock of an infectious substance, that contains an infectious substance and is generated in the diagnosis, treatment, or immunization of human beings or animals; research pertaining to the diagnosis, treatment, or immunization of human beings or animals; or the production or testing of biological products. Project: GP05, M29, QMS28 NOTE 1: Exceptions include wastes that have been treated by steam sterilization, chemical disinfection, or other appropriate method, so that they no longer pose the hazard of an infectious substance; corpses, remains, and anatomical parts that are intended for ceremonial interment or cremation; and hazardous wastes; NOTE 2: See medical waste and regulated waste.
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regulated waste liquid or semiliquid blood or other potentially infectious materials; contaminated items that would release blood or other potentially infectious materials in a liquid or semiliquid state if compressed; items that are caked with dried blood or other potentially infectious materials and are capable of releasing these materials during handling; contaminated sharps; and pathological and microbiological wastes containing blood or other potentially infectious materials. See medical waste and regulated medical waste Project: M29
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regulation rule based on and meant to carry out a specific law to control, direct, or manage an activity, organization, or system Project: QMS14, QMS16, QMS17
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regulations rules promulgated by federal, state, or local authorities to implement laws enacted by legislative bodies Project: I/LA33
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regulatory agencies agencies that provide the legal permission for laboratories to operate and oversee the registration of proficiency testing organizations NOTE: Examples include agencies such as Center for Medicare & Medicaid Services, state health departments, and national or regional ministries of health.
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regulatory agency a government agency with the assignment to enforce regulations passed by legislative process Project: MM14 NOTE 1: Agencies that provide the legal permission for laboratories to operate. These agencies may also oversee the approval or registration of proficiency testing/external quality assessment organizations; NOTE 2: Examples include agencies such as the Centers for Medicare & Medicaid Services and state health departments in the United States and national or regional ministries of health.
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regulatory organization authority established by government to specify requirements for competence for specific analytical activities and to designate authority to accreditation organizations Project: QMS24
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reimbursement the process by which healthcare providers receive payment for their services Project: GP45 NOTE: Because of the nature of the healthcare environment, providers are often reimbursed by third parties who insure and represent patients.
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rejection limit as used in EP26, the fraction of the critical difference used to determine whether the observed average lot-to-lot difference indicates acceptable lot-to-lot performance at the chosen statistical power Project: EP26
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relative centrifugal field (RCF) the outward-directed centrifugal acceleration of an object moving in a circle at constant angular velocity Alternate Term: RCF NOTES: a) the term “rotative centrifugal force” is widely used for RCF. However the actual quantity–relative centrifugal field–is dimensionless; thus, it is not a force and should not be called a force; b) This can be confused with revolutions per minute (rpm)
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relative centrifugal force the amount of accelerative force applied to a particle in a centrifuge depending on its perpendicular distance from the rotor axis at a given moment in time Project: PRE04
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relative density the ratio of the density of the system and the density of a “reference” or “standard” system, under conditions that should be specified for both systems (IUPAC/IFCC1978-4.25) NOTE: When the reference system is water, the term commonly used is “specific gravity.”
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relative error error of measurement divided by a true value of the measurand NOTE Since a true value cannot be determined, in practice a conventional true value is used. (VIM93)
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relative fluorescence intensity (RFI) an arbitrary value reported by a fluorometer that expresses the magnitude of an FI measurement as a relative proportion of other FI measurements taken under identical conditions Project: I/LA24
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relative frequency the frequency divided by the total number of occurances or observations (ISO 3534-1/93-2.13)
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relative humidity the ratio of water vapor in the air to the amount that would saturate it at a specific temperature
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relative risk 1) ratio of the risk (ie, the probability or rate of occurrence) of an outcome in exposed vs unexposed groups, synonymous with risk ratio; 2) alternatively, the ratio of the cumulative incidence rate in the exposed to the cumulative incidence rate in the unexposed, synonymous with rate ratio; 3) the rate of disease in one group exposed to a particular factor divided by the rate in another group which is not exposed Project: GP45 NOTE 1: The term relative risk has also been used synonymously with odds ratio (q.v.) and, in some biostatistical articles, has been used for the ratio of measures of the occurrence of death or other outcomes, often termed the forces of morbidity by epidemiologists and demographers; NOTE 2: The use of the term relative risk for several different quantities arises from the fact that for “rare” diseases (eg, most cancers with incidence rates measured as cases per 10,000 or 100,000), all the quantities approximate one another; for common occurrences (eg, neonatal mortality in infants under 1500 g birth weight), the approximations do not hold; NOTE 3: A relative risk of one indicates that the two groups have the same rate of disease.
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relative standard deviation See and use "standard deviation"
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relative standard measurement uncertainty standard measurement uncertainty divided by the absolute value of the measured quantity value (JCGM 200:2012) Project: ISO IEC Guide 99
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relative standard measurement uncertainty standard measurement uncertainty divided by the absolute value of the measured quantity value different from zero (modified from JCGM 200:2008 § 2.32) Project: C51 NOTE 1: The relative standard measurement uncertainty of a quantity x is formally symbolized u(x)/|x|; NOTE 2: When the relative standard measurement uncertainty is expressed in percentage form, 100 × u(x)/|x|, it can be symbolized %u(x).
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release (secretion) the event associated with the liberation of platelet alpha or dense granule contents after the introduction of a platelet agonist on a metabolically intact platelet Project: H58
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reliability in GP47, the probability that all critical- and significant-risk results will be successfully communicated to a responsible caregiver Project: GP47 NOTE: It is calculated as the number of results successfully reported to a caregiver divided by the total number of results monitored.
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reliability the ability of a system or component to perform its required functions under stated conditions for a specified period of time (IEEE 610.12-1990) Project: AUTO08, H02, H48
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reliability probability that an item will perform its required function under given conditions for a stated time interval Project: EP23
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reliability the ability of a test system to give consistently accurate and precise results Project: POCT08, POCT15
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remains general term for deceased persons, including body parts Project: GP36 NOTE: Synonymous with “decedent.”
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remedical action action taken to rectify a recognized nonconformance NOTE: Remedial action usually does not remove the root cause of the problem
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remote site generally applies to the health care organization location Project: AUTO09
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repair actions carried out after fault detection to effect restoration (modified from ISO 14224) Project: QMS23
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repeat field a single data element which expresses a duplication of the field definition it is repeating Project: LIS2 NOTE: It is used for demographics, requests, orders and the like, where each element of a repeat field is to be treated as having equal priority or standing to associated repeat fields
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repeat screening (requested) any subsequent screening test(s) performed on an additional specimen that was collected because the previous screening specimen had an out-of-range or screen-inconclusive result or was deemed unacceptable for testing Project: NBS03, NBS02, NBS13, NBS10 Source: Newborn Screening Glossary NOTE: See screen inconclusive and specimen acceptability.
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repeat screening (routine) any subsequent screening test(s) performed on an additional specimen that was collected as part of the screening program’s routine practices Project: NBS02, NBS03, NBS13, NBS10 Source: Newborn Screening Glossary NOTE: Routine repeat screening might be performed by two-screen programs, as well as by programs that routinely collect multiple specimens (eg, from low birth weight newborns).
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repeat testing newborn screening testing that requires a specimen to be recollected Project: NBS04 NOTE: Reasons necessitating specimen recollection include the initial or primary specimen was collected before 24 hours of age, was unacceptable for testing (eg, low birth weight premature newborns, newborns who have received blood transfusions), or yields abnormal or inconclusive results.
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repeatability (measurement) measurement precision under a set of repeatability conditions of measurement (JCGM 200:2012) Alternate Term: measurement repeatability Project: EP10, ISO IEC Guide 99, I/LA33, C43, MM06, I/LA28, GP34, I/LA34, EP21, MM01, MM20, EP26, C40, MM22, MM09, H60, EP05, C62, EP15, MM23, POCT06, EP19, MM21, QMS24, EP07, MM17, MM24, EP39, H62 NOTE 1: For the purpose of immunohematological testing, this is typically confined to challenging the automated system’s ability to render the same interpretation consistently; NOTE 2: Formerly termed “within-run precision” was used in CLSI EP05 and CLSI EP15; NOTE 3: Sometimes referred to as “within-run precision”; NOTE 4: Repeatability conditions include the same measurement procedure, the same observer, and the same measuring instrument, all used under the same conditions, in the same location, and repeated over a short period of time (modified from JCGM 200:2012); NOTE 5: In the laboratory, it is often called “within-assay,” “within-run,” “intra-assay,” or “intra-run” precision; NOTE 6: Measurement of the smallest amount of imprecision that would be observed for an assay when most of the sources of variation are controlled (eg, replicates of the sample are tested on the same run using the same reagent lot, same instrument, and same operator at a single site).
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repeatability one of several support media to which either target or probe nucleic acids are immobilized Project: MM02 NOTE: Examples include nylon or nitrocellulose membrane, beads, magnetic particles, and microtiter plate wells.
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repeatability measurement precision (closeness of agreement between indications or measured quantity values obtained by replicate measurements on the same or similar objects under specified conditions) is a set of repeated measurements that includes the same measurement procedure, same operators, same measuring system, same operating conditions, and same location, and replicate measurements on the same or similar objects over a short period of time (modified from JCGM 200:2012) Project: EP23
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repeatability (of results of measurements) closeness of the agreement between the results of successive measurements of the same measurand carried out under the same conditions of measurement Project: H57, I/LA23, C48, H54, MM10, MM12, QMS07, H20, H47 NOTE 1: These conditions are called repeatability conditions; NOTE 2: Repeatability conditions include the same measurement procedure, the same observer, the same measuring instrument, used under the same conditions, the same location, repetition over a short period of time; NOTE 3: Repeatability may be expressed quantitatively in terms of the dispersion characteristics of the results; NOTE 4: Repeatability is often termed in laboratory medicine “within-run precision”; NOTE 5: It is often termed in the laboratory as “within-assay,” “within-run,” “intra-assay,” and “intra-run” precision; NOTE 6: Same conditions imply same method, same observer, same instrument, same location, same condition of use, and repeated over a short space of time.
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repeatability precision under conditions from which independent test results are obtained with the same method on identical test items in the same laboratory by the same operator using the same equipment within short intervals of time (modified from ISO 5725-1) Project: ISO 15197, C50, POCT14 NOTE 1: ISO 3534-1 defines repeatability as “precision under repeatability conditions”; NOTE 2: Formerly, the term within-run precision was used in CLSI documents.
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repeatability precision under repeatability conditions (ISO 15198) Project: ISO 15198
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repeatability (of a measuring instrument) ability of a measuring instrument to provide closely similar indications for repeated applications of the same measurand under the same conditions of measurement (VIM93) Project: MM12, MM16, H20, H57 NOTE 1: These conditions include: reduction to a minimum of the variations due to the observer; the same measurement procedure; the same observer; the same measuring equipment used under the same conditions; the same location; and repetition over a short period of time (VIM93); NOTE 2: Repeatability may be expressed quantitatively in terms of the dispersion characteristics of the indications (VIM93).
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repeatability the closeness of agreement between results from the same sample within a single test run Project: EP12-IG, EP12
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repeatability condition (of measurement) condition of measurement, out of a set of conditions that includes the same measurement procedure, same operators, same measuring system, same operating conditions, and same location, and replicate measurements on the same or similar objects over a short period of time (JCGM 200:2012) Alternate Term: repeatability condition of measurement Project: ISO IEC Guide 99, GP16, I/LA21, I/LA33, I/LA28, GP34, EP26, C40, I/LA26, EP06, EP05, EP15, MM23, POCT06, EP19, MM21, QMS24, EP30, H62, MM01 NOTE 1: A condition of measurement is a repeatability condition only with respect to a specified set of repeatability conditions (JCGM 200:2012); NOTE 2: In chemistry, the term “intra-serial precision condition of measurement” is sometimes used to designate this concept (JCGM 200:2012); NOTE 3: Repeatability is often termed in laboratory medicine as “within-run precision”; NOTE 4: For the purpose of immunohematological testing, this is typically confined to challenging the automated system’s ability to render the same interpretation consistently; NOTE 5: In chemistry, the terms “within-run,” “intraserial,” or “intrarun precision condition of measurement” are sometimes used to designate this concept (modified from JCGM 200:2012); NOTE 6: Conditions in which independent measurement results are obtained with the same method of measurement on identical samples (or test items) in the same laboratory (or location) by the same operator using the same equipment within a short interval of time (ISO 15198); NOTE 7: For the purposes of ISO 17593, “laboratories” should be interpreted as “locations” (ISO 17593); NOTE 8: Essentially unchanged conditions, intended to represent conditions resulting in minimum variability of test results (ISO 15198); NOTE 9: Repeatability can be determined from replicated measurements made under the repeatability conditions and also from differences between duplicate measurements made within various runs on different days. The latter method is used with experimental designs described in EP05.
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repeatability conditions conditions where independent test results are obtained with the same method on identical test material in the same laboratory by the same operator using the same equipment within a short interval of time (modified from ISO 17593) Project: ISO 15198, H20, I/LA28, MM20, H60 NOTE 1: Essentially unchanged conditions, intended to represent condition resulting in minimum variability of test results (modified from ISO 17593); NOTE 2: Formerly termed within-run precision.
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repeatability conditions conditions where independent measurement results are obtained with the same method of measurement on identical samples in the same laboratory by the same operator using the same equipment within short intervals of time (ISO 17593) Project: ISO 17593, EP07 NOTE 1: Essentially unchanging conditions, intended to represent conditions resulting in minimum variability of measurement results (ISO 17593); NOTE 2: For the purposes of ISO 17593, “laboratories” should be interpreted as “locations” (ISO 17593).
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repeatability of measurement precision of measurement under repeatability conditions (ISO 17593) Project: ISO 17593
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repeats multiple independent testing portions of an on-test product Project: EP25 EXAMPLE: Vials of a control material are evaluated with a stability study. A predefined number of vials (the repeats) are obtained at each time point, with a predefined number of replicate measurements made from each of the vials; NOTE: As an example, consider putting vials of a control material into a stability study. A predefined number of vials (the repeats) are taken at each time point, with a predefined number of replicate measurements made on each of the vials.
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replicate a value resulting from a repeat analysis of the same specimen Project: EP09
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replicate to perform a measurement procedure more than once under repeatability conditions using the same or a similar starting test sample (verb); a value resulting from repeat independent analysis of the same or a similar starting test sample by a measurement process under repeatability conditions (noun) Project: EP15 NOTE 1: Unless otherwise defined by the manufacturer, the starting point for the measurement process is assumed to follow specimen acquisition and generic processing (eg, centrifugation) and before the start of measurand-specific processing steps in the measurement procedure; NOTE 2: Replicates are obtained by processing each starting test sample in a separate sample cup or equivalent (ie, one test result per sample cup).
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replicate a value resulting from a repeat examination of the same sample or similar objects, if appropriate Project: EP12
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replication the repetition of a complete set of all of the treatments to be compared in an experiment NOTE: Each of the repetitions is called a “replicate” (ISO3534-3/85-1.10).
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report document giving detailed information on a reference material, supplementary to that contained in a certificate or package insert Project: prEN12287:1998 NOTE The information may comprise the preparation of the reference material, methods of measurement, factors affecting trueness, statistical treatment of results, and the way in which traceability was established.
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report document giving detailed information on a reference material, supplementary to that contained in a certificate (ISO 15194) Project: ISO 15194
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reportable range a set of values of analytes for which the error of a measuring instrument is intended to lie within specified limits Project: M52, MM21, POCT17 NOTE 1: The range of test-result values over which the laboratory can establish or verify the accuracy of the instrument, kit, or test system measurement response; NOTE 2: In some fields, the term is “measuring range” or “measurement range.”
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reportable range a set of values of measurands for which the error of a measuring instrument is intended to lie within specified limits Project: I/LA23, POCT04, POCT09, MM20, MM22, MM24 NOTE 1: In this document, the term reportable range (United States) is equivalent to measuring range (Europe); NOTE 2: The range of test-result values over which the laboratory can establish or verify the accuracy of the instrument, kit, or test system measurement response; NOTE 3: See measuring interval.
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reportable range in nucleic acid sequence analysis, the region of the genome that is sequenced and reported at an acceptable level of quality Project: MM09
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reportable range the range of test values over which the relationship between the instrument, kit, or system’s measurement response is shown to be valid (US CFR 493 February 28, 1992) Alternate Term: measuring range; working range Project: H44, MM06 NOTE 1: For EP06, the range of values (in units appropriate for the analyte) over which the acceptability criteria for the method have been met; that is, where errors due to nonlinearity, imprecision, or other sources are within defined limits; NOTE 2: This is similar to the VIM definition for “measuring range” or “working range,” ie, a set of values of measurands for which the error of a measuring instrument is intended to lie within specified limits; NOTE 3: The reportable range of the assay should be established prior to beginning the clinical evaluation; NOTE 4: The preferred international term is “measuring range.”
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reported result the value, in appropriate units, that is reported to the healthcare provider
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reporting time frame the time that elapses from when the laboratory becomes aware of the finalized result until the result is reported to the responsible caregiver Project: GP47
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reproducibility (measurement) measurement precision under reproducibility conditions of measurement (JCGM 200:2012) Alternate Term: measurement reproducibility Project: MM13, POCT14, H58, I/LA33, C43, M51, MM06, H59, I/LA28, GP34, H02, I/LA34, M53, EP21, MM19, MM01, MM20, MM07, EP09, C40, MM22, MM09, H60, EP05, C62, C57, MM23, POCT06, EP19, M52, MM21, H48, POCT04, QMS24, MM17, NBS05, MM24, EP39, H62, EP12, M23, EP12-IG, POCT16 NOTE 1: Relevant statistical terms are given in international standards (ISO 5725-1, ISO 5725-2, JCGM 200:2012); NOTE 2: For the purpose of immunohematological testing, reproducibility is typically confined to challenging the automated system’s ability to render the same interpretation consistently; NOTE 3: More broadly defined as the agreement between repeated measurements on the same specimen under different conditions; NOTE 4: The closeness of agreement between the results of the measurements of the same measurand carried out under changed conditions of measurement; NOTE 5: Changed conditions may include principle or method of measurement, observer, measuring instrument, location, conditions of use, and time; NOTE 6: Reproducibility conditions include different locations, operators, measuring systems, and replicate measurements on the same or similar objects (modified from JCGM 200:2012); NOTE 7: In chemistry, the terms “between-laboratories,” “interlaboratory,” or “among-laboratories precision condition of measurement” are sometimes used to designate this concept; NOTE 8: The ability of a product, within lots and across multiple lots, to produce the same results, when used in different settings (eg, different sites, different operators, different instruments); NOTE 9: The measure of the closeness of the results obtained when analyzing the same sample more than once; NOTE 10: The measure of agreement between replicate measurements of the same material; NOTE 11: Changed conditions may include principle or method of measurement, observer, measuring instrument, reference standard, location, conditions of use, and time; NOTE 12: Several types of reproducibility often are used in laboratory medicine: “between-assay,” “between-run,” “interassay,” “inter-run,” “interoperator,” “interanalyst,” and “interlaboratory” precision. The operative conditions should always be specified; NOTE 13: As with blood cell counts, viable cells have different properties compared with dead cells, which may limit the duration of day-to-day studies; NOTE 14: The operative conditions should always be specified; NOTE 15: For EP12, reproducibility conditions of measurement may, contain interinstrument or interlaboratory data; NOTE 16: Several types of reproducibility often are used in laboratory medicine: “between-assay,” “between-run,” “interassay,” “inter-run”, and “interlaboratory” precision. The operative conditions should always be specified; NOTE 17: Precision can be affected by different parameters (eg, disk lot, media lot) being used, measurements being made by different operators, or measurements being made over a period of time.
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reproducibility in bacterial strain typing, the closeness of agreement between results obtained when the same method is applied; a) to multiple isolates representing a single strain (as defined by strict epidemiologic criteria); or b) for replicates derived from subculture of a single isolate; the multiple assessments may be made over time in a single laboratory or in different laboratories Project: MM11 NOTE: Reproducibility in bacterial strain typing is influenced by both technical and biologic factors.
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reproducibility precision under conditions where test results are obtained with the same method on identical test items in different laboratories with different operators using different equipment (ISO 5725-1) Project: ISO 15197 (April 2001), GP28, C50 NOTE: ISO 3534-1 [3.20] defines reproducibility as “precision under reproducibility conditions.”
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reproducibility ability of a product, within lots and across multiple lots, to produce the same results, while used under different conditions (eg, different sites, different operators, different instruments) Project: M50
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reproducibility precision under reproducibility conditions (ISO 15198) Project: ISO 15198
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reproducibility condition (of measurement) condition of measurement, out of a set of conditions that includes different locations, operators, measuring systems, and replicate measurements on the same or similar objects (JCGM 200:2012) Alternate Term: reproducibility condition of measurement Project: ISO IEC Guide 99, ILA29, GP16, I/LA21, I/LA33, M51, I/LA28, GP34, H02, MM19, C51, EP09, C40, I/LA26, H60, EP05, C57, MM23, POCT06, EP29, EP19, M52, MM21, POCT04, QMS24, NBS04, EP30, NBS05, MM01 NOTE 1: The different measuring systems may use different measurement procedures (JCGM 200:2012); NOTE 2: A specification should give the conditions changed and unchanged, to the extent practical (JCGM 200:2012); NOTE 3: The changed conditions may refer to different lots, runs, time (day), technicians, etc.; NOTE 4: For the purpose of immunohematological testing, this is typically confined to challenging the automated system’s ability to render the same interpretation consistently; NOTE 5: In chemistry, the terms “between-laboratories,” “interlaboratory,” or “among-laboratories precision condition of measurement” are sometimes used to designate this concept.
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reproducibility conditions conditions where test results are obtained with the same method on identical test items in different laboratories with different operators using different equipment (modified from ISO 17593) Project: ISO 15198, ISO 17593, I/LA28 NOTE 1: Completely changed conditions are intended to represent conditions resulting in maximum variability of test results (ISO 17593); NOTE 2: For the purposes of ISO 17593, “laboratories” should be interpreted as “locations” (ISO 17593).
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reproducibility of measurement precision of measurement under reproducibility conditions (ISO 17593) Project: ISO 17593
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reptilase time a functional plasma clotting assay based on the enzymatic activity of batroxobin (also called reptilase), which acts by specifically cleaving fibrinogen A fromfibrinogen, leading to the formation of a stable fibrin clot recorded in seconds Project: H48 NOTE: The reptilase time is usually performed to confirm orto exclude the suspicion of dysfibrinogenemias because this test is independent of thrombin generation disturbances or disturbances in the action of thrombinon fibrinogen and the result will be normal in the presence of heparin but prolonged in dysfibrinogenemias.
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request for information a formal means to request information about a potential supplier’s products or services, which enables using a structured process for reducing a long list of potential suppliers to a smaller number Project: QMS21
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request for proposal a solicitation document offered by an organization to elicit bids from potential suppliers for procuring a product or service through the respondent’s business proposals Project: QMS21
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request for quote a variation of a request for proposal that typically provides the bidder with more information about the procurement project’s requirements and often requires the bidder to detail costs for each project phase to allow comparison of different bids by the soliciting organization Project: QMS21
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requirement 1) a condition or capability needed by a user to solve a problem or achieve an objective; 2) a condition or capability that must be met or possessed by a system or system component to satisfy a contract, standard, specification, or other formally imposed documents; 3) a documented representation of a condition or capability as in definitions 1) or 2) above (IEEE 610.12-1990) Project: AUTO08
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requirement for the purposes of QMS17, refers to the individual statement established by the assessment organization to which the laboratory needs to adhere to be considered compliant Project: QMS17 NOTE: Requirements can include regulations, standards, checklist items, or customer expectations.
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requirement need or expectation that is stated, generally implied, or obligatory (ISO 9000) Project: QMS01, QMS16, QMS21 Source: Quality Glossary NOTE 1: A specified requirement is one that is stated, for example, in documented information (ISO 9000); NOTE 2: “Generally implied” means that it is custom or common practice for the organization and interested parties that the need or expectation under consideration is implied (ISO 9000); NOTE 3: A qualifier can be used to denote a specific type of requirement, eg, product requirement, quality management requirement, customer requirement, quality requirement (ISO 9000); NOTE 4: Requirements can be generated by different interested parties or by the organization itself (ISO 9000); NOTE 5: It can be necessary for achieving high customer satisfaction to fulfill an expectation of a customer even if it is neither stated nor generally implied or obligatory (ISO 9000).
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research use only product labeled by the manufacturer as: “For research use only. Not for use in diagnostic procedures” Project: MM07
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reservoir in water purification systems, a container holding quantities of purified water Project: GP40
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residual the difference between a given data point and its predicted value Project: I/LA24, EP09 NOTE 1: As used in this guideline for evaluating FI calibration curves, the residual is calculated from the fluorochrome dose as: [Observed Value - Reference Value], where the observed value has been interpolated from the calibration curve and the reference value is the assigned value in relative or absolute units. Absolute residual - The absolute value of the residual. Percent residual - The residual expressed as a percentage, positive or negative, of the reference value, calculated as: [100 X ({Observed Value - Reference Value}/Reference Value)]. Absolute percent residual - The absolute value of the percent residual. Average absolute percent residual - The sum of the absolute percent residuals for all calibrator data points in a calibration curve divided by the number of data points, ie, the average percent difference, positive or negative, between the observed and expected values of all standards used to generate the calibration curve; NOTE 2: This value gives the most basic evaluation of linearity for the entire FI calibration curve; NOTE 3: As used in EP09, for evaluating a value predicted by a regression fit.
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residual patient sample the amount of original sample or extracted sample left after the testing ordered by the physician is completed and reported out by the medical laboratory Project: MM17
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residual risk risk remaining after risk control measures have been taken (ISO 14971) Project: ISO 14971, ISO 18113-1, EP23, MM17 NOTE 1: ISO/IEC Guide 51:1999 uses the term "protective measures" rather than "risk control measures." However, in the context of ISO 14971, "protective measures" are only one option for controlling risk; NOTE 2: Residual risks are disclosed to users in the instructions for use. See ISO 14971:2007, Annex H.
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residual risk risk remaining after risk control (mitigation) measures have been taken (modified from ISO 14971) Project: EP18
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resistant (R) for breakpoints, bacterial strain inhibited in vitro by a concentration of an antimicrobial agent that is associated with a high likelihood of therapeutic failure (ISO 20776-1) Project: ISO 20776-1, ISO 20776-2 NOTE 1: Bacterial strains are categorized as resistant by applying the appropriate breakpoints in a defined phenotypic test system (ISO 20776-1); NOTE 2: This breakpoint can be altered due to changes in circumstances (eg, changes in commonly used drug dosages, emergence of new resistance mechanisms) (ISO 20776-1).
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resistant antimicrobial susceptibility test interpretive category a category that implies that isolates are not inhibited by the usually achievable concentrations of the agent with normal dosage schedules and/or that demonstrate MICs that fall in the range where specific microbial resistance mechanisms (eg, β-lactamases) are likely, and clinical efficacy of the agent against the isolate has not been reliably shown in treatment studies
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resistant antimicrobial susceptibility test interpretive category resistant isolates that are not inhibited by the usually achievable concentrations of the agent with normal dosage schedules or where clinical efficacy has not been reliable in treatment studies
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resistant antimicrobial susceptibility test interpretive category a category that implies that isolates are not inhibited by the usually achievable concentrations of the agent with normal dosage schedules
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resistant antimicrobial susceptibility test interpretive category a category that implies that isolates are not inhibited by the usually achievable concentrations of the agent with normal dosage schedules and/or that demonstrate MICs or zone diameters that fall in the range where specific microbial resistance mechanisms (eg, β-lactamases) are likely, and clinical efficacy of the agent against the isolate has not been reliably shown in treatment studies
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resistant antimicrobial susceptibility test interpretive category 1) for critical concentration, resistance is defined as diminished susceptibility of a strain that differs from wild-type strains from patients who have not been treated with the drug, so that the strain is unlikely to show clinical responsiveness to the drug; 2) for minimal inhibitory concentration, resistant isolates are not inhibited by the usually achievable concentrations of the agent at the site of infection with normal dosage schedules, and/or fall in the range where specific microbial resistance mechanisms are likely (eg, beta-lactamases), and clinical efficacy has not been reliable in treatment studies
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resistant antimicrobial susceptibility test interpretive category resistant isolates are not inhibited by the usually achievable concentrations of the agent with normal dosage regimens and/or fall in the range in which specific microbial resistance mechanisms are likely (eg, β-lactamases), and clinical efficacy has not been reliable in treatment studies Project: VET05
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resistant antimicrobial susceptibility test interpretive category a category that implies that isolates are not inhibited by the usually achievable concentrations of the agent with normal dosage regimens and/or fall in the range in which specific microbial resistance mechanisms are likely (eg, β-lactamases), and clinical efficacy has not been reliable in treatment studies Project: VET04
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resistant breakpoint the lowest minimal inhibitory concentration or the largest zone diameter value for which the interpretive category is considered resistant Project: M39 NOTE: See interpretive category.
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resistivity (specific resistance) 1) the ratio of electric intensity to cross-sectional area; 2) the resistance between opposite faces of a one-centimeter cube of a given material at a specified temperature Alternate Term: specific resistance NOTE: Resistivity is also the reciprocal of conductivity.
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resistivity the electrical resistance between opposite faces of a 1-cm cube of a given material at a specified temperature Project: GP40 NOTE 1: Resistivity is the reciprocal of conductivity; NOTE 2: For water analysis, resistivity is usually reported in megohm-centimeters (MΩ·cm).
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resolution (of a displaying device) smallest difference between displayed indications that can be meaningfully distinguished (JCGM 200:2012) Project: ISO IEC Guide 99, C52 NOTE: Resolution, when applied to chromatographic procedures, relates to the effectiveness of the system in separating components of a mixture.
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resolution smallest change in a quantity being measured that causes a perceptible change in the corresponding indication (JCGM 200:2012) Project: ISO IEC Guide 99 NOTE: Resolution can depend on, for example, noise (internal or external) or friction. It may also depend on the value of a quantity being measured (JCGM 200:2012).
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resolution degree to which an instrument can detect and report small changes in the signal being measured Project: I/LA24
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resolution (of a displaying device) smallest difference between indications of a displaying device that can be meaningfully distinguished Project: VIM93, MM24 NOTE 1: For a digital displaying device, this is the change in the indication when the least significant digit changes by one step (VIM93); NOTE 2: This concept applies also to a recording device (VIM93); NOTE 3: In DNA sequencing, the ability to clearly distinguish between adjacent positions (VIM93); NOTE 4: Resolution is influenced by the parameters of electrophoresis, sequence ladder peak height (signal strength), and peak width (VIM93); NOTE 5: Resolution, when applied to chromatographic procedures, relates to the effectiveness of the system in separating components of a mixture.
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resolution the ability to discriminate between cells or particles having different signal intensities Project: H42, H43, H52 NOTE: The ability to resolve discrete populations is a function of biological factors (heterogeneity of signal within each population, difference in signal intensities between populations), as well as instrumental factors (sensitivity, measurement coefficient of variation).
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resolution in DNA sequencing, the ability to clearly distinguish between adjacent positions Project: MM09
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resolution the ability to resolve or clearly separate the positive signal from the negative or background Project: H62 NOTE: Resolution can depend on, for example, noise (internal or external). It may also depend on the value of a quantity being measured (JCGM 200:2012).
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resolution conventionally defined in mass spectrometry as the m/z divided by Δ(m/z), where Δ(m/z) is the peak width in the mass spectrum at a given m/z value Alternate Term: mass spectral resolution Project: C64, NBS04, C50 NOTE 1: Peak width can be determined through several nonequivalent approaches. Common practice is measurement of the peak width at the point where the intensity is half the maximal peak height (full width at half maximum); NOTE 2: The peak width can be measured in several different ways; however, common practice has become the measurement of the width of the peak at the point where the intensity is half the peak height, owing to the “skirting” of peaks that may be sometimes observed in quadrupole and time-of-flight analyzers; NOTE 3: The 10% valley method of calculation of mass resolution is typically used for experiments using sector-based mass spectrometers; NOTE 4: Mass resolution is distinct from chromatographic resolution.
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resource-limited setting geographical region or setting in which there are limited or scarce resources (eg, financial), resulting in a lack of access to quality diagnostic testing Project: M48
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response the extent to which an output signal is functionally related to the measurand Project: DI01
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response activities carried out during an incident that draw upon previous mitigation and preparedness efforts, in order to minimize the effect of an incident Project: GP36
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response direct measure of the pharmacologic effect of the drug with regard to the drug’s safety and efficacy. A variety of clinical end points and biomarkers may be used Project: M23
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response the provision of emergency services and public assistance during or immediately after an emergency or disaster in order to save lives, reduce health impacts, ensure public safety, and meet the basic subsistence needs of the people affected Project: POCT16
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response characteristic relationship between a stimulus and the corresponding response, for defined conditions; EXAMPLE: the e.m.f. (electromotive force) of a thermocouple as a function of temperature; EXAMPLE: the e.m.f. (electromotive force) of a thermocouple as a function of temperature NOTES 1: The relationship may be expressed in the form of a mathematical equation, a numerical table, or a graph. When the stimulus varies as a function of time, one form of the response characteristic is the transfer function (the Laplace transform of the response divided by that of the stimulus).
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response factor the relationship between the detector response and measurand concentration Project: C64
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response slope the change in potential, usually given in millivolts, divided by the difference of the logarithms of two different ionized calcium concentrations Project: C39 NOTE: The theoretical response slope of a calcium ISE toward calcium ion is 30.77 mV/log unit at 37°C; the ideal millivolt change between 1.25 and 2.50 mmol/L ionized calcium in this designated comparison method is 9.255 mV.
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response time time interval between the instant when a stimulus is subjected to a specified abrupt change and the instant when the response reaches and remains within specified limits around its final steady value
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responsible caregiver a licensed practitioner who is responsible for managing a patient in response to critical- and significant-risk laboratory results Project: GP47
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responsive the degree to which the assay is affected by the stated condition Project: H60
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responsiveness the degree of prolongation of the clotting time induced by a particular reagent/instrument system to plasma-related factors (eg, decreased vitamin K-dependent factor activities or concentration of sodium citrate) Project: H54 NOTE: The longer the clotting time to a given factor activity, the more responsive the reagent/instrument system.
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restriction endonucleases including any of a large family of bacterial enzymes that recognizes a specific DNA sequence and cleaves the DNA at or near that site Project: MM24
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restriction enzyme restriction endonuclease, including any of a large family of bacterial enzymes that recognizes a specific DNA sequence and cleaves the DNA at or near that site Project: MM10
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restriction enzyme restriction endonuclease; including any of a large family of bacterial enzymes that cleave double-stranded DNA at specific nucleotide sequences Project: MM12
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restriction fragment length polymorphism an example of a type of DNA polymorphism Project: MM01, MM12 NOTE: An RFLP is usually a dimorphism defined by the presence or absence of a specific restriction endonuclease cutting site. When size-based analysis such as gel or capillary electrophoresis is used, with or without the inclusion of analysis probes (eg, Southern blotting), the allele containing the cutting site will be seen as one or two shorter fragments, and the allele without the cutting site will be seen as a longer, intact fragment. The pattern of the DNA fragments depends on whether the polymorphism creates or destroys a novel restriction endonuclease recognition site.
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result (measurement) set of quantity values being attributed to a measurand together with any other available relevant information (JCGM 200:2012) Alternate Term: measurement result Project: ISO IEC Guide 99, ISO 18113-1, C56, EP06 NOTE 1: A measurement result generally contains “relevant information” about the set of quantity values, such that some may be more representative of the measurand than others. This may be expressed in the form of a probability density function (JCGM 200:2012); NOTE 2: A measurement result is generally expressed as a single measured quantity value and a measurement uncertainty. If the measurement uncertainty is considered to be negligible for some purpose, the measurement result may be expressed as a single measured quantity value. In many fields, this is the common way of expressing a measurement result (JCGM 200:2012); NOTE 3: In the traditional literature and in the previous edition of the VIM, measurement result was defined as a value attributed to a measurand and explained to mean an indication, an uncorrected result, or a corrected result, according to the context (JCGM 200:2012); NOTE 4: In many fields of metrology, a measurement result is expressed as a single measured quantity value and a measurement uncertainty. In laboratory medicine, measurement results are usually expressed as single measured quantity values (ISO 18113-1).
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result (of a measurement) value attributed to a measurand, obtained by measurement Alternate Term: measurement result, result of a measurement NOTES:
1 When a result is given, it should be made clear whether it refers to:
- the indication
- the uncorrected result
- the corrected result
and whether several values are averaged.
2 A complete statement of the result of a measurement includes information about the uncertainty of measurement.
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result of measurement See measurement result Project: C51
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result segment See observation segment Project: AUTO02
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result verification a process that is known by a variety of names, such as verifying, accepting, or releasing of results by the laboratory staff, so the results are made available or accessible to care providers outside the laboratory, such as physicians, nurses, and so on Project: I/LA33 NOTE: The process implies that results have been examined and meet the quality criteria established by the laboratory, and can be used in the treatment and management of patients/donors.
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retest the same test applied to a punched sample from the same dried blood spot specimen to obtain replicate results as part of the activity within the newborn screening laboratory process Project: NBS06, NBS07, NBS10 Source: Newborn Screening Glossary NOTE: The new sample may be punched from the same or different dried blood spot on the original dried blood spot specimen. However, it should be of the same diameter and from the same relative location within a dried blood spot, because samples taken from different locations within a dried blood spot may produce different analytical results.
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reticulocyte transitional red cells between nucleated red cells and the so-called mature erythrocyte; 2) An erythrocyte that, when stained with a supravital dye (eg, NMB), contains stainable nucleic acids (ie, cellular RNA) or when stained with fluorescent reagents with specificity of binding to nucleic acids shows increased cellular fluorescence Project: H44 NOTES: a) To be identified as a reticulocyte by visual microscopy, the cell must contain two or more distinct blue-staining granules (NMB-reticulocyte) that are visible without requiring fine focus microscope adjustment on the individual cell to confirm their presence; b) The granules should be away from the cell margin to avoid confusion with Heinz bodies.
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reticulocyte hemoglobin content (CHr) reticulocytes, similar to the mature erythrocyte, contain hemoglobin as the primary oxygen-carrying molecule Project: H44 NOTE: Measurement of the hemoglobin content can be performed and quantitated in terms of mean picogram of hemoglobin per cell.
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retirement a phase in the Implementation Stage of the Test Life Phases Model. The Retirement Phase involves removal of the test method from service Project: EP19
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reusability the degree to which a software module or other work product can be used in more than one computer program or software system Project: AUTO08
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reverse group tests plasma or serum with reagent red blood cells to detect naturally occurring antibody(ies) present in the serum or plasma; a positive reaction (hemagglutination) indicates the presence of the corresponding antibody in the serum or plasma; a negative reaction (no hemagglutination) indicates the absence of the corresponding antibody in the serum or plasma Project: I/LA33 NOTE: Formerly known as reverse type or back type.
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reverse osmosis a process in which water is forced under pressure through a semipermeable membrane, leaving behind dissolved organic, dissolved ionic, and suspended impurities Project: GP40
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reverse osmosis process in which a solution under pressure is forced through a filter from a more concentrated to a less concentrated solution
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reverse passive agglutination a modification of the indirect agglutination assay in which particles are coated with an antibody, which in turn become probes for detecting specific antigen in test material by article agglutination Project: DL01
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reverse pipetting technique recommended for pipetting solutions with a high viscosity (such as blood) or those which tend to foam Project: H42 NOTE: The advantage is reduction of errors due to fluid film retention. Reverse pipetting is only possible with air displacement pipettes. The sequence of operations is reversed as compared to standard pipetting: more fluid is initially aspirated than will be dispensed, and the remainder is discarded (see Section 7.5.2.3 for a detailed description).
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reverse transcriptase quantitative polymerase chain reaction a quantitative reverse transcriptase polymerase chain reaction assay designed to quantify gene expression Project: MM05
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reverse transcription the process of enzymatically synthesizing complementary DNA from an RNA template Project: MM22, MM24
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reverse-transcriptase polymerase chain reaction a polymerase chain reaction assay designed to detect RNA targets by making a DNA copy of RNA and then performing polymerase chain reaction Project: MM05, POCT15
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review determination of the suitability, adequacy, or effectiveness of an object to achieve established objectives (ISO 9000) Project: QMS06, QMS14, QMS16
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review activity undertaken to determine the suitability, adequacy, and effectiveness of the subject matter to achieve established objective (modified from ISO 9000) Project: QMS03
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rhabditoid larvae noninfective, thick, rod-shaped larvae of hookworm and Stronglyloides stercoralis; rhabditoid refers to the shape of the larval esophagus Alternate Term: rhabditiform larvae Project: M28
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Rheumatoid factor antibodies in patient samples that react with one or more classes of immunoglobulins of human (and sometimes other species) origin; it can be class- or subclass-specific Project: DI01
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rheumatoid factors antibodies that bind to the constant or Fc portion of other immunoglobulins Project: I/LA30
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ribonuclease a type of nuclease that catalyzes the degradation of RNA into smaller components Project: MM19
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ribonuclease P gene a common term for the human ribonuclease P RNA component H1 (RPPH1) gene Project: NBS06 NOTE: A segment of the ribonuclease P gene sequence is used as a genomic reference polymerase chain reaction product in some T-cell receptor excision assays.
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ribonucleic acid a single-stranded nucleic acid similar to DNA but having ribose sugar rather than deoxyribose sugar and uracil rather than thymine; found in the nucleus and cytoplasm of cells, it plays an important role in protein synthesis and other chemical activities of the cell Project: MM13 NOTE 1: There are several classes of RNA molecules, including messenger RNA, transfer RNA, ribosomal RNA, and other small RNAs, each serving a different purpose; NOTE 2: A mixture containing all RNA entities is termed “total RNA.”
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Rijndael designed by Joan Daemen and Vincent Rijmen, Rijndael is a symmetric block cipher with a variable block size of 128, 192, or 256 bits and a variable key length of 128, 192, or 256 bits Project: AUTO09 NOTE: Rijndael is the algorithm used in the US Advanced Encryption Standard; however, in Advanced Encryption Standard, only the 128-bit block size is used.
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risk the probable rate of occurrence of a hazard causing harm and the degree of severity of the harm (ISO Guide 63-2.11) Project: POCT02
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risk combination of the probability of occurrence of harm and the severity of that harm (ISO 15190) Project: QMS01, M29, HS11, GP40, EP18, EP23, QMS16, GP47, QMS21, EP31, QMS17 Source: Quality Glossary NOTE 1: In CLSI EP18, the combination of frequency of occurrence and severity is also risk; NOTE 2: A potential hazard or quality deficiency associated with a process, product, or service.
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risk combination of the likelihood of an incident and the severity of the harm (consequences) if that incident were to occur Project: QMS28
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risk analysis systematic use of available information to identify hazards and to estimate the risk (ISO/IEC Guide 51) Project: ISO 15198, ISO/IEC Guide 51, ISO/DIS 14971, EP18, EP23, GP47 NOTE: Risk analysis includes examination of different sequences of events that can produce hazardous situations or harm.
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risk analysis investigation of available information to identify hazards and estimate risks (ISO 14971) Project: ISO 17593 (January 2002), ISO DIS 17593
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risk assessment overall process composed of a risk analysis and a risk evaluation (ISO/IEC Guide 51) Project: ISO IEC Guide 51, ISO DIS 14971, EP18, I/LA33, EP23, GP47, M48 NOTE 1: Risk is a measure of the probability and severity of undesired effects. It is often taken as the simple product of probability and consequence; NOTE 2: Risk assessment is a comprehensive evaluation of risk and its associated impact; NOTE 3: In mycobacterial testing, a thorough workplace evaluation performed to identify practices, situations, etc., that may cause harm (eg, Mycobacterium tuberculosis complex infection) to the laboratory worker; NOTE 4: Due to the potential presence of Mycobacterium tuberculosis complex in patient specimens and its ability to form infectious droplet nuclei when aerosolized, laboratories need to ensure appropriate practices are in place to protect their laboratory workers. Because laboratories vary widely in service levels and number of specimens processed, no single set of safety guidelines can be applied to all laboratories. Thus, a risk assessment should be performed by each laboratory. After the risk severity is identified, measures can be implemented to effectively protect or control harm to the laboratory worker in a particular laboratory setting; NOTE 5: The risk of these practices can be stratified into low, medium, and high risk.
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risk assessment scientific evaluation of known or potential adverse effects resulting from hazards Project: GP40 NOTE: The process consists of the following steps: hazard, or potential hazard, identification; evaluation of the impact of the hazard; and assessment of the practicality of measures to mitigate the risk from the hazard.
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risk control process in which decisions are made and measures implemented by which risks are reduced to, or maintained within, specified levels (ISO/DIS 14971) Project: ISO/DIS 14971 NOTE: Instructions for use, precautions, warnings, limitations, contraindications, and performance characteristics are considered risk controls. See ISO 14971 for guidelines.
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risk control measure action taken to reduce or maintain risks within specified levels (ISO 18113-1)
Project: ISO 18113-1 NOTE 1: Risk control measures based on labelling are called information for safety in ISO 14971 and are considered the least effective risk control option in order of risk management priority. Labelling intended as information for safety includes instructions for use, limitations of the procedure, precautions, warnings (ISO 18113-1); NOTE 2: General guidance on providing information for safety is provided in Annex J of ISO 14971:2007. General guidance for evaluating information for safety as a risk control measure, including review of warnings and review of the operating instructions, is provided in D.7 of ISO 14971:2007 (ISO 18113-1); NOTE 3: Specific guidance pertaining to information for safety of IVD medical devices is provided in Annex H of ISO 14971:2007 (ISO 18113-1); NOTE 4: Derived from ISO 14971:2007, definition 2.19 (ISO 18113-1).
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risk estimation process used to assign values to the probability of occurrence of harm and the severity of that harm (ISO 14971) Project: ISO 14971, EP23, GP47
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risk evaluation process of comparing the estimated risk against given risk criteria to determine the acceptability of the risk (ISO 14971) Project: ISO 14971, EP23, GP47
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risk group categorization of infectious agents based on factors such as pathogenicity, virulence, host range, and mode of transportation. There is no accepted consensus on risk group categorization, even within government agencies or among biosafety professionals Project: M29
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risk management systematic application of management policies, processes, procedures, and practices to the tasks of analyzing, evaluating, controlling, and monitoring risk (modified from ISO 14971) Project: QMS01, EP18, EP23, GP47 Source: Quality Glossary
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risk management process concerned with the identification, measurement, control, and minimization of risks to an acceptable level Project: POCT02 NOTE: Risk management includes risk analysis, risk evaluation, risk reduction and risk control.
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risk management file set of records and other documents that are produced by risk management (ISO 14971) Project: ISO 14971
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risk mitigation a process designed to prevent or detect microbial identification system malfunction Project: M50
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ristocetin a substance originally developed as an antibiotic and then found to cause platelet clumping in the presence of normal von Willebrand factor Project: H51 NOTE: The extent of platelet clumping in the presence of an optimal concentration of ristocetin is directly proportional to the concentration of functional von Willebrand factor.
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ristocetin a substance originally developed as an antibiotic and then found to cause platelet clumping in the presence of normal von Willebrand factor; NOTE: The extent of platelet clumping in the presence of an optimal concentration of ristocetin is directly proportional to the concentration of functional von Willebrand factor Project: H51
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ristocetin a substance originally developed as an antibiotic and then found to cause platelet clumping in the presence of normal von Willebrand factor Project: H51 NOTE: The extent of platelet clumping in the presence of an optimal concentration of ristocetin is directly proportional to the concentration of functional von Willebrand factor.
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ristocetin cofactor activity (R:CoF) the functional activity of von Willebrand factor that induces platelet agglutination in the presence of ristocetin Project: H51
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ristocetin-induced platelet agglutination (RIPA) platelet agglutination in citrated platelet-rich plasma in the presence of different concentrations of ristocetin Project: H51
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Rivest Cipher #2 a proprietary, variable-key-length block cipher invented by Ron Rivest for RSA Data Security, Inc. (now a wholly owned subsidiary of Security Dynamics, Inc.) (RFC 2828) Project: AUTO09
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Rivest Cipher #4 a proprietary, variable-key-length stream cipher invented by Ron Rivest for RSA Data Security, Inc. (now a wholly owned subsidiary of Security Dynamics, Inc.) (RFC 2828) Project: AUTO09
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Rivest Cipher #5 a symmetric block cipher designed by Ronald Rivest in 1994 that uses a block size of 32 to 128 bits and a key length of 0 to 2040 bits Project: AUTO09 NOTE: The number of encryption rounds may range from 0 to 255.
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Rivest Cipher #6 a symmetric block cipher based on Rivest Cipher #5 and designed by Rivest, Sidney, and Yin Project: AUTO09 NOTE: The block size, the key size, and the number of rounds are variable. The upper limit on the key size is 2040 bits. Rivest Cipher #6 was one of the five final candidates for the US Advanced Encryption Standard.
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Rivest-Shamir-Adleman an algorithm for asymmetric cryptography, invented in 1977 by Ron Rivest, Adi Shamir, and Leonard Adleman. Rivest-Shamir-Adleman uses exponentiation modulo the product of two large prime numbers. The difficulty of breaking Rivest-Shamir-Adleman is believed to be equivalent to the difficulty of factoring integers that are the product of two large prime numbers of approximately equal size (RFC 2828) Project: AUTO09
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robotic arm a device capable of moving a specimen container, specimen carrier, or another object in the X, Y, and Z directions Project: AUTO01, AUTO02 NOTE: Unless this device is an integral part of the laboratory automation system, it is considered an instrument for the purpose of AUTO01.
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robust standard deviation based on the deviation of individual data points to the median of the population (classical standard deviation is a function of the deviation of individual data points to the mean of the population) Project: H62 NOTE 1: For perfectly normal distributions, both classical standard deviation and robust standard deviation would provide the same result. However, if the population is skewed, has a few outlying events, or is off scale, it can be difficult to accurately define the limits of the distribution. A robust statistic determines the peak and uses a percentage (typically 50% to 70%) of the events falling around the peak to set the upper and lower boundaries of the distribution to calculate the robust standard deviation; NOTE 2: See standard deviation.
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robustness the ability of an assay to proceed optimally, despite slight variation in conditions Project: MM01, MM09 NOTE: Usually refers to polymerase chain reaction, in which amplification occurs despite slight changes in reaction conditions, such as DNA concentration.
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robustness of an in vitro diagnostic assay, refers to the degree of tolerability and independence of the performance of its crucial elements to variability in the operator(s), deviations in the properties of the individual constituents, environmental conditions, or the protocol Project: I/LA28
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robustness study study/analysis/evaluation, performed during product development, to ascertain performance of a product at the limits being claimed; refers to product parameters (eg, inoculum concentration, temperature, age of culture) Project: M50
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ROL an Health Level Seven abbreviation for a role segment Project: AUTO01, AUTO02, AUTO03
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role segment in Automation, a segment containing the data necessary to revise the records of the person(s) involved, as well as their functional involvement in the activity being transmitted (HL7 V2.6) Project: AUTO01, AUTO02, AUTO03
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rolling veins superficial venous vasculature that is not firmly anchored superficially and that moves laterally during venous access attempts Project: PRE02
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Romanowsky type stains any stain containing methylene blue and/or its products of oxidation (azure B), and a halogenated fluorescein dye, usually eosin B or Y Project: H56
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room temperature the temperature prevailing in a working area Project: M40
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room temperature the temperature prevailing in a working area; “controlled room temperature” is a temperature maintained thermostatically that encompasses the usual and customary working environment of approximately 18 to 25°C Project: MM13, H21, H59, PRE05, H48 NOTE: Labeling can indicate storage at “controlled room temperature” or “up to 25°C.”
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room temperature thermostatically maintained indoor air temperature that encompasses the normal working environment of 20 to 25°C with brief deviations. For the purposes of PRE04, room temperature can range from 15 to 25°C Project: PRE04
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root cause the most basic reason for a problem, which, if corrected, will reduce or eliminate recurrence of that problem Project: QMS24
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root cause analysis systematic process for identifying “root causes” of problems or events and an approach for responding to them (Washington State Department of Enterprise Services. Root cause analysis. https://des.wa.gov/services/risk-management/about-risk-management/enterprise-risk-management/root-cause-analysis) Project: EP23 NOTE: Root cause analysis is based on the idea that effective management is not merely “managing unexpected emeregencies” for problems that develop but finding a way to prevent them.
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root cause analysis systematic approach for identifying the causal factor(s) underlying a problem or condition Project: QMS01, GP26, GP33 Source: Quality Glossary NOTE: Regulatory bodies may require use of the term “root cause analysis” to ensure confidentiality of root cause analysis documents.
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root cause analysis process for identifying the basic or causal factor(s) that underlies variation in performance, including the occurrence or possible occurrence of a nonconforming event Project: QMS17
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rotating radius the distance measured from the rotor axis to the base of the tube at the greatest horizontal distance from the rotor axis Project: PRE04
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router a computer that is a gateway between two networks at Open System Interconnection layer 3 and that relays and directs data packets through that internetwork. The most common form of router operates on Internet Protocol packets (RFC 2828) Project: AUTO09
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routine examiner a person of average training and skill (eg, a person certified as a medical technologist or medical technician) who performs routine laboratory studies Project: H20
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routine laboratory method that method being used routinely in the laboratory, in contrast to the reference method (see reference method), which is not ordinarily used in routine laboratory operations Project: H20
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routine second screen a second screening test performed on an older newborn after an interval (usually one to two weeks after birth) as part of the local protocol for all newborns
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routine test disk diffusion or broth or agar dilution minimal inhibitory concentration tests for routine clinical testing Project: M02, M07, VET01
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RPMI 1640 a cell culture medium developed at the Roswell Park Memorial Institute and commonly used for in vitro assays involving hematopoietic cells Project: I/LA26
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ruggedness (of a measuring system) the precision and accuracy of the method are insensitive to minor changes in environmental and procedural variables, laboratories, and personnel Project: C43 NOTE: Many method development or verification protocols require that sensitivity to particular parameters be investigated directly. This is usually done by a preliminary ruggedness test, in which the effect of one or more parameter changes is observed. If significant (compared with the precision of the ruggedness test), a more detailed study is carried out to measure the size of the effect, and a permitted operating interval chosen accordingly. Ruggedness test data can therefore provide information on the effect of important parameters.
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rule one of a set of explicit or understood regulations or principles governing conduct or procedure within a particular area of activity Project: AUTO15
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rule stringency a subjective level of scrutiny in the detail of a rule set that will lead to either lower or higher levels of autoverification rates but may also lead to greater risk or error depending on the rule set’s complexity (and corresponding algorithm) Project: AUTO15
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run 1) an interval within which the accuracy and precision of a testing system is expected to be stable, but cannot be greater than 24 hours or less than the frequency recommended by the manufacturer; 2) an interval within which the accuracy and precision of a testing system is expected to be stable, but it cannot be greater than the frequency recommended by the manufacturer Project: EP10, H26, I/LA28, EP15 NOTE 1: ISO defines “run” as follows: In a series of observations of a qualitative characteristic, the occurrence of an uninterrupted series of the same attribute is called a “run” (ISO 3534-1/93-2.48); NOTE 2: Between analytical runs, events may occur that render the measurement process susceptible to important variations; NOTE 3: For the CLSI EP10 protocol, run is defined as a sequence of samples analyzed consecutively without interruption, unless the recommended operation requires such interruption. In particular, there should not be any recalibration within this recommended sequence.
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run an interval within which the analytical performance of a testing system is expected to be stable, but it cannot be longer than the time period recommended by the manufacturer Project: EP12 NOTE 1: Between analytical runs, events may occur that render the measurement process susceptible to important variations; NOTE 2: A sequence of samples examined consecutively without interruption, unless the recommended operation requires such interruption; NOTE 3: A run or batch is the time interval or conditions of measurement for which the imprecision of measurement is the lowest. Therefore, the precision of measurements within a run defines repeatability.
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run series of measurements within which the trueness and precision of the measuring system are expected to be stable Project: C51, C62, C63 NOTE 1: In a series of observations, the occurrence of an uninterrupted series of the same quantity is called a “run”; NOTE 2: Between analytical runs, events can occur that render the measurement process susceptible to important variations; NOTE 3: May be referred to as a “batch.”
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run length the actual interval of a run
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safety freedom from unacceptable risk of harm (ISO Guide 63-2.12) Project: ISO Guide 63-2.12, ISO Guide 63-2.12
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safety freedom from unacceptable risk (ISO/IEC Guide 51) Project: ISO 18113-1, ISO 18113-2, ISO 18113-3, ISO IEC Guide 51, ISO DIS 14971
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safety assessment code (SAC) method for determining whether any further definitive action is required concerning a particular incident, based on the severity of the incident and its probability of occurrence
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safety device See sharps with engineered sharps injury protections Project: M29
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safety hood covering over a medical laboratory workplace or device to reduce risk to a laboratory worker Project: ISO15190 (March 2002)
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safety program institutional general safety, biosafety, biosecurity, chemical, radiological, and emergency response programs and plans that all staff are required to follow to manage possible workplace hazards Project: M29
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sales packaging see outer container
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saline a solution of 0.85% to 0.9% NaCl (w/v) Project: M07, M02, VET01, M11
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sample one or more parts taken from a specimen (modified from ISO 15189) Project: ISO 15189, GP28, H54, GP26, MM13, MM03, I/LA02, MM12, ISO 18113-1, ISO 18113-2, ISO 18113-3, MM01, H56, H20, C49, H58, POCT05, H42, H43, H47, H57, C34, M55, GP33, H26, GP39, H59, GP34, H02, M53, C58, PRE05, MM19, NBS05, C51, C56, MM20, EP09, EP26, C40, MM22, MM09, H52, H60, C62, C57, MM23, POCT06, H48, QMS24, EP34, EP31, NBS04, C63, MM17, QMS22, PRE01, NBS09, NBS08, EP35, POCT08, POCT15, MM24, PRE04, NBS10 EXAMPLE 1: A volume of serum taken from a larger volume of serum; EXAMPLE 2: A portion of serum taken from a specimen of coagulated blood; EXAMPLE 3: An unbiased or randomly selected subset of a population of measurement results; NOTE 1: A sample is prepared from the patient specimen, commonly a portion of the specimen, and used to obtain information by means of a specific laboratory test; NOTE 2: In CLSI QMS02, the term “sample” replaces the term “specimen”; however, for the purposes of this guideline, readers can consider the terms equivalent; NOTE 3: The system from which a sample is taken might not be of the same type as that of the measurand. For example, a given blood sample may serve for measurement of pH in plasma hemoglobin concentration in erythrocytes; NOTE 4: A sample is any type of sample obtained from a patient, not limited to blood; NOTE 5: In the context of CLSI H18, a sample may be serum or plasma, available (for testing) after centrifugation of the specimen, or whole blood; NOTE 6: For the purposes of CLSI EP34, a specimen or portion of a specimen that is modified by dilution or spiking is no longer a specimen but rather is a sample; NOTE 7: For newborn dried blood spot screening, the sample is a punch taken from a dried blood spot specimen; NOTE 8: A sample is prepared from the patient specimen and used to obtain information by means of a specific laboratory test; NOTE 9: For the purposes of CLSI C34, a sample may be physically or chemically changed from the original patient specimen (see specimen), as in having been spiked with a potentially interfering substance; NOTE 10: In the context of CLSI EP35, a sample is that portion of a specimen used for analytical testing after specimen processing; NOTE 11: A portion of a specimen can also be referred to as an aliquot; NOTE 12: In relation to carryover, a sample is a clinical specimen or surrogate sample being analyzed using the test method being investigated. The measurement obtained for the sample may be affected by carryover from preceding samples or by reagents used for other tests on the same measuring system.
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sample a portion or aliquot withdrawn from a container for the test Project: AUTO01, AUTO07, AUTO02 NOTE 1: In automation, samples are typically not placed in containers that will have to be uniquely identified, but may go directly into the instrument or specimen processing and handling device test stream or may be placed in sample cups unique to the instrument or specimen processing and handling device; NOTE 2: In automation, the identification of the specimen is typically ensured by computer linkage of the pipetting or aspiration step to the identification of the container from which it was obtained, or by a separate numbering system for the sample cups that is internal to the analytical instrument or specimen processing and handling device.
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sample (primary) collection of one or more parts initially taken from a system and intended to provide information about the system, or to serve as a basis for a decision about the system (ISO 15193) Alternate Term: specimen Project: ISO 15193, EP10, C24 NOTE 1: In some cases, the information provided also applies to a larger system or a set of systems, of which the sampled system is an element (ISO 15193); NOTE 2: A sample is prepared from the patient specimen and used to obtain information by means of a specific laboratory test; NOTE 3: The system from which a sample is taken may not be of the same type as that of the measurand. For example, a given blood sample may serve for measurement of the pH in plasma, or for measurement of the hemoglobin concentration in erythrocytes; NOTE 4: For the purposes of this guideline, the term “sample” is used to denote nonhuman or modified human materials such as quality control materials, calibrators, or proficiency testing/external quality assessment materials; NOTE 5: For example, a volume of serum taken from a larger volume of serum.
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sample (patient) a sample taken from the patient specimen and used to obtain information by means of a specific laboratory test Project: H47, H44, H51, GP43, H30, GP16 NOTE: ISO 15189 defines sample as “one or more parts taken from a system, and intended to provide information on the system, often to serve as a basis for decision on the system or its production”; EXAMPLE: A volume of serum taken from a larger volume of serum.
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sample one or more parts taken from a population and intended to provide information on the population (ISO 15198) Project: ISO 15198, EP18, MM14 EXAMPLE: A volume of serum taken from a larger volume of serum (ISO 15189).
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sample in POCT14, a sample taken from the patient specimen and used to obtain information by means of a specific laboratory test Project: POCT14, I/LA26 NOTE: ISO 15189 defines sample as “one or more parts taken from a primary sample”; EXAMPLE: A volume of serum taken from a larger volume of serum (ISO 15189).
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sample one or more parts taken from a system and intended to provide information on the system, often to serve as a basis for decision on the system or its production (modified from ISO 18113-1) Project: MM06, MM19, H21, POCT16 NOTE 1: For example, a volume of serum taken from a larger volume of serum; NOTE 2: A sample is prepared from the patient specimen and used to obtain information by means of a specific laboratory test.
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sample one or more parts taken from a system and intended to provide information about the system or to serve as a basis for a decision about the system (modified from ISO 15193) Project: EP23, EP27, EP07, EP39, EP12, EP25, EP33 EXAMPLE: A volume of serum taken from a larger volume of serum (ISO 15189); NOTE 1: For the purposes of EP07, EP12, and EP39, a sample may be physically or chemically changed from the original patient specimen (see specimen), as in having been spiked with a potentially interfering substance; NOTE 2: In EP25, “sample” is used to indicate a patient specimen or other sample (eg, patient, control, contrived material) being used to support the stability testing.
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sample 1) a portion or aliquot withdrawn from a container for the test; 2) one or more parts taken from a system, and intended to provide information on the system, often to serve as a basis for decision on the system or its production (ISO 15189) Project: AUTO12, AUTO14 NOTE 1: In automation, a) samples may not be placed in containers that have to be uniquely identified, but may go directly into the instrument or specimen processing and handling device test stream or may be placed in sample cups unique to the instrument or specimen processing and handling device; NOTE 2: In automation, the identification of the specimen is typically ensured by computer linkage of the pipetting or aspiration step to the identification of the container from which it was obtained, or by a separate numbering system for the sample cups that is internal to the analytical instrument or specimen processing and handling device; NOTE 3: One or more parts taken from a system, and intended to provide information to the system, often to serve as a basis for decision on the system or its production
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sample one or more representative parts taken from a system, which are intended to provide information on the system (ISO 18113-1) Alternate Term: specimen Project: ISO 18113-1 EXAMPLE: A portion of serum taken from a primary sample of coagulated blood (modified from ISO 15189); NOTE 1: “Sample” can also be defined as an aliquot from a primary patient specimen (or from what ISO 18113 calls “primary sample”), or a derivative of a specimen, such as a cell line or diluted aliquot; NOTE 2: Statisticians use “sample” in a different though related sense, to refer to a selection of a representative set from a larger population for statistical testing.
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sample a small part of anything, or one of a number, intended to show the quality, style, or nature of the whole; one or more parts taken from a specimen
Project: H62 NOTE 1: For the purposes of H62, readers can consider the terms “sample” and “specimen” equivalent; NOTE 2: “Sample” may also refer to a nonpatient sample such as a quality control sample.
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sample a small part of anything, or one of a number, intended to show the quality, style, or nature of the whole; specimen
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sample (patient) one or more parts taken from a primary sample (specimen) (ISO 15189) Project: C52 NOTE: A portion of an original specimen collected by or submitted to a laboratory for testing.
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sample (processsed) for the purposes of EP14, a processed sample is intended to mimic one obtained from a specimen Project: EP14 NOTE 1: It is considered a processed sample if it has been modified in any way that causes it to be different from a specimen, eg, freezing, lyophilization, adding nonendogenous substances or stabilizers; NOTE 2: For EP14, these are the materials being evaluated for matrix effects.
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sample (unprocessed) one or more parts taken from a specimen (ISO 15189) Project: EP14 NOTE 1: In the context of EP14, an unprocessed sample is the portion of a specimen used in a measurement procedure; NOTE 2: In EP14, unprocessed samples may also be called patient samples; EXAMPLE: A volume of serum taken from a larger volume of serum (ISO 15189).
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sample carrier See specimen carrier Project: AUTO02, AUTO12, AUTO01
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sample container See specimen collection container Project: Auto01, AUTO12, AUTO02
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sample exchange exchange and testing of blinded samples between laboratories to assess proficiency Project: MM14, QMS24 NOTE: Can be used as alternative assessment when proficiency testing is not available.
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sample probe See specimen probe Project: AUTO02
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sample size 1) the number of participants in the trial; 2) intended sample size – the number of participants planned to be included in the trial, usually determined using a statistical power calculation; 3) achieved sample size – the number of participants enrolled, treated, or analyzed in the study Project: GP45 NOTE: The sample size should be adequate to provide a high probability of detecting as significant an effect size of a given magnitude if such an effect actually exists.
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sample size number of samples used in the experiment comparing two measurement procedures Project: EP27
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sample-positioning system See specimen-positioning system Project: AUTO01, AUTO02
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sampling device an object (often made of plastic material, but may also be composed of glass tubes, fiber buds, or wood sticks) with a carrier, used to obtain the specimen containing the microorganism Project: M40 NOTE 1: This carrier can be fitted with absorbent material (eg, cotton, wool, synthetic polyester, rayon, polyurethane [foam]); NOTE 2: The holder of the collection (sampling) device can be integrated into the design of the cap of the transport system.
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sampling plan a plan for selecting samples (test samples or product samples) that includes (but is not limited to) a count of the number of replicates or a selection scheme across a production lot(s) or production time period Project: EP25
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sampling port part of the indwelling catheter tubing that provides sterile access to urine in the catheter Project: PRE05
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sandwich immunoassay an immunoassay that uses the chemical or immunochemical binding of the analyte to a solid phase and the immunochemical binding of a second (labeled) reagent to the analyte Project: DL01
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sandwich immunoassay a capture antibody, specific for the antigen, is immobilized onto a solid phase, such as a polystyrene test tube or a microtiter plate well. The detecting antibody binding the same or a different epitope of the antigen is labeled with an enzyme or other reporter that is used as a signal-generating system. This can be used as a homogeneous assay Alternate Term: two-site immunometric assay Project: H59
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Sanger sequencing a DNA chain termination sequencing method based on controlled interruption of DNA strand elongation by dideoxynucleotides Project: MM18
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sanitation process to reduce the presence of most pathogenic bacteria Project: ISO15190 (March 2002)
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sanitization chemical and/or physical processes used to kill microorganisms and reduce contamination from microorganisms Project: M40, GP40
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sans serif a font style without serifs Project: AUTO12 NOTE: Serifs are any of the short lines stemming from and at an angle to the upper and lower ends of the strokes of the letter.
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SaO2 oxygen saturation of arterial blood Project: POCT11
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saprobic feeding on dead or decaying organic material; often used interchangeablywith saprophytic
Project: M54
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satellite accumulation the act of collecting hazardous waste at or near its point of generation Project: GP05 NOTE: The Environmental Protection Agency has requirements on how large- and small-quantity generators may accumulate chemical waste on-site.
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saturate to combine one substance with another to the greatest extent possible through solution, chemical combination, or the like
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scalable in disaster planning, refers to the capability of the emergency operations plan and responders to dynamically match response potency with incident intensity, throughout the life of the disaster event Project: GP36
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scalable algorithms an algorithm capable of being modified such that the addition of decision points ensures the algorithm is “backwards compatible” Project: AUTO15
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scale (of a measuring instrument) ordered set of marks, together with any associated numbering, forming part of a displaying device of a measuring instrument NOTE Each mark is called a scale mark. (VIM93-4.17)
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scale division part of a scale between any two successive scale marks
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scale factor the difference between the label value of sample 1 (low concentration) and 2 (mid-level concentration) of the samples used in the CLSI EP10 protocol Project: EP10
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scale interval difference between the values corresponding to two successive scale marks NOTE Scale interval is expressed in the units marked on the scale, regardless of the units of the measurand.
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scale length for a given scale, length of the smooth line between the first and last scale marks and passing through the centres of all the shortest scale marks NOTE 1 The line may be real or imaginary, curved or straight. NOTE 2 Scale length is expressed in units of length, regardless of the units of the measurand or the units marked on the scale.
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scale numbering ordered set of numbers associated with the scale marks
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scale of a displaying measuring instrument part of a displaying measuring instrument, consisting of an ordered set of marks together with any associated quantity values (JCGM 200:2008) Project: ISO IEC Guide 99
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scale spacing distance between two successive scale marks measured along the same line as the scale length NOTE Scale spacing is expressed in units of length regardless of the units of the measurand or the units marked on the scale.
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scaling the operation of adjusting the total or average intensity of each array to be approximately the same to an arbitrary constant Project: MM16 NOTE: Scaling can be done by multiplying each value by a scaling factor (a ratio) that can be determined by comparing the total average intensity of each array to an arbitrary constant.
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scan rate the speed at which a scanning mass spectrometer scans across a particular mass range Project: C50 NOTE 1: In quadrupole instruments, this is typically defined as a number of m/z units per second (eg, 100 m/z/s); NOTE 2: Different considerations must be given to sector instruments and time-of-flight instruments.
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scatter diagram graphical quality technique or tool to analyze the relationship between two variables
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scatter plot a graphical representation consisting of a set of points whose coordinates x and y on ordinary rectangular axes are the values of characteristics X and Y (ISO 3534-1/93-2.21) Alternate Term: scatter diagram Project: ISO 3534-1/93-2.21 NOTE: The concept of a scatter diagram can be extended to more than two characteristics (ISO 3534-1/93-2.21).
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scatter plot a type of mathematical diagram using Cartesian coordinates to display values for two variables for a set of data Alternate Term: scatter diagram Project: EP09 NOTE 1: The data are displayed as a collection of points, each having the value of one variable determining the position on the horizontal axis and the value of the other variable determining the position on the vertical axis; NOTE 2: Also called scatter chart, scattergram, scatter diagram, or scatter graph.
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schema-referenced value in some laboratory information systems, specimen tracking may be carried out by use of bar codes that contain, in the machine-readable area, a numerical code that correlates to the database row number, and not the accession number itself. In such cases, the accession number may differ from the content of the bar code, making it beneficial to render the human-readable text below the bar code with both the accession number as well as the bar code numerical contents (thus facilitating tracking and error recovery exercises) Project: AUTO12
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schematic design second design phase of a construction project, in which information from the first phase (planning and programming) is used to create a floor plan
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sclerotic bodies thick-walled, dematiaceous, muriform, rounded cells seen in tissue that are diagnostic of chromoblastomycosis Project: M54
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scolex the head or attachment portion of a tapeworm; attachment may be by suckers or hooklets (Taenia, Diphyllobothrium spp.) Project: M28
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screen inconclusive a final, reportable result, based on the newborn screening result(s) and laboratory screening algorithm for a screened disease, group of diseases, or phenotypic difference, indicating the inability to accurately interpret the screening result, typically leading to a request for a repeat dried blood spot specimen Source: Newborn Screening Glossary NOTE: See repeat screening (requested).
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screen negative a final, reportable result for a disease, group of diseases, or phenotypic difference, based on the newborn screening result(s) and laboratory screening algorithm, indicating that the risk for that disease, group of diseases, or phenotypic difference is low and that no additional newborn screening follow-up is needed Project: NBS06, NBS05, NBS07, NBS09 Source: Newborn Screening Glossary NOTE 1: Also referred to as a “negative screening result”; NOTE 2: In the T-cell receptor excision circle assay, a final, reportable T-cell receptor excision circle result that is above the preset T-cell receptor excision circle cutoff value; NOTE 3: In the acid α-glucosidase activity assay, a final, reportable acid α-glucosidase activity result that is above the preset acid α-glucosidase activity cutoff value.
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screen positive a final, reportable result for a disease, group of diseases, or phenotypic difference, based on the newborn screening result(s) and laboratory screening algorithm, indicating that the risk for that disease, group of diseases, or phenotypic difference is higher and that additional follow-up is needed Project: NBS06, NBS05, NBS07, NBS09 Source: Newborn Screening Glossary NOTE 1: Also referred to as a “positive screening result” or a “presumptive positive result”; NOTE 2: An out-of-range result might not be equivalent to a screen-positive result when more than one screening test (eg, both a first-tier test and a second-tier test) is used in a laboratory screening algorithm to determine the final, reportable result; NOTE 3: A final screen-positive result might necessitate either a repeat screening request (eg, if a program considers borderline results to indicate “possible” [vs “probable”] disease) or referral for diagnostic testing and/or clinical evaluation; NOTE 4: Individual newborn screening programs might use differing definitions of the term “screen positive” internally (eg, they might include both results indicating the need for additional clinical follow-up and results indicating that a repeat newborn screening specimen needs to be requested); however, using a consistent definition of “screen positive” across programs enables consistent comparison of screening metrics; NOTE 5: Newborn screening algorithms determine under which circumstances a positive screening result requires immediate clinical evaluation and/or a repeat newborn screening specimen; NOTE 6: In the severe combined immunodeficiency newborn screening assay, a final, reportable T-cell receptor excision circle result that is below the previously determined T-cell receptor excision circle cutoff value; NOTE 7: In the acid α-glucosidase activity assay, a final, reportable acid α-glucosidase activity result that is below the previously determined cutoff value; NOTE 8: See re-collection and repeat screening (requested).
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screen results false-negative screening result – screen-negative result in an affected newborn; NOTE 1: A screen-negative result indicating that an individual is not at increased risk for the primary target disease when the individual is found later to be affected; NOTE 2: See primary target disease.
false-positive screening result – screen-positive result in an unaffected newborn; NOTE 1: A screen-positive result indicating that an individual is at increased risk for a target disease when the individual is found later to be unaffected; NOTE 2: See primary target disease.
screen inconclusive – a final, reportable result, based on the newborn screening result(s) and laboratory screening algorithm for a screened disease, group of diseases, or phenotypic difference, indicating the inability to accurately interpret the screening result, typically leading to a request for a repeat dried blood spot specimen; NOTE: See repeat screening (requested).
screen negative – a final, reportable result for a disease, group of diseases, or phenotypic difference, based on the newborn screening result(s) and laboratory screening algorithm, indicating that the risk for that disease, group of diseases, or phenotypic difference is low and that no additional newborn screening follow-up is needed; NOTE: Also referred to as a “negative screening result.”
screen positive – a final, reportable result for a disease, group of diseases, or phenotypic difference, based on the newborn screening result(s) and laboratory screening algorithm, indicating that the risk for that disease, group of diseases, or phenotypic difference is higher and that additional follow-up is needed; NOTE 1: Also referred to as a “positive screening result” or a “presumptive positive result”; NOTE 2: An out-of-range result might not be equivalent to a screen-positive result when more than one screening test (eg, both a first-tier test and a second-tier test) is used in a laboratory screening algorithm to determine the final, reportable result; NOTE 3: A final screen-positive result might necessitate either a repeat screening request (eg, if a program considers borderline results to indicate “possible” [vs “probable”] disease) or referral for diagnostic testing and/or clinical evaluation; NOTE 4: Individual newborn screening programs might use differing definitions of the term “screen positive” internally (eg, they might include both results indicating the need for additional clinical follow-up and results indicating that a repeat newborn screening specimen needs to be requested); however, using a consistent definition of “screen positive” across programs enables consistent comparison of screening metrics; NOTE 5: See re-collection and repeat screening (requested).
true-negative screening result – screen-negative result in an unaffected newborn.
true-positive screening result – screen-positive result in an affected newborn. Project: NBS02, NBS13, NBS10 Source: Newborn Screening Glossary
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screening the systematic application of a test or inquiry, to identify individuals at sufficiently high risk of a specific disorder to benefit from further investigation or direct preventive action, among persons who have not sought medical attention on account of symptoms of that disorder Project: I/LA25
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screening identification of unrecognized disease or defect. Example, prenatal screens for neural tube defects Project: ISO15196 (June 2001)
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screening algorithm logic process used to determine whether a particular dried blood spot specimen yields a positive, negative, or inconclusive screening result Project: NBS07, NBS03
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screening model the test or combination of tests used to screen for a disease Project: NBS10 Source: Newborn Screening Glossary NOTE: See laboratory screening algorithm.
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screening outcome the combined results of the entire screening process in terms of epidemiological parameters; see table below | Final Screening Result | Affected | Unaffected | Total | | Positive | True positive (a) | False positive (b) | Screen positive (a + b) | | Negative | False negative (c) | True negative (d) | Screen negative (c + d) | | Total | Total affected (a + c) | Total unaffected (b + d) | Total screened (a + b + c + d) | (Table reprinted with permission from the International Society for Neonatal Screening, Lexicon of Terms to be used in newborn screening. https://www.isns-neoscreening.org/wp-content/uploads/2016/06/Lexicon8.pdf)Project: NBS13, NBS09, NBS05, NBS02, NBS10 Source: Newborn Screening Glossary NOTE: See clinical sensitivity, clinical specificity, positive predictive value, recall rate, screen negative, screen positive, and screen results.
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screening test the systematic application of determinations (ie, measurement procedures, physiological evaluations, or assessments) among a defined population (eg, newborns) with the goal of detecting individuals at sufficient risk for a specific disease, group of diseases, or phenotypic difference to merit additional investigation or guide preventive action Project: NBS02, NBS03, NBS05, NBS13, NBS09, NBS10 Source: Newborn Screening Glossary NOTE 1: Although sometimes used in a more generalized sense, in NBS02, the term “screening test” refers specifically to the determination(s), not to the other elements of the newborn screening system; NOTE 2: See first-tier screen, second-tier screen, third-tier screen, and newborn screening system.
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screening test 1) a method used to evaluate large populations of individuals for the presence of a disease or analyte; 2) generally used to evaluate the genetic status of an asymptomatic individual who is not at increased risk due to a positive family history Project: MM10, MM12
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screening test a test to systematically identify individuals at sufficiently high risk of a specific disorder to benefit from further investigation or direct preventive action, among persons who have not sought medical attention on account of symptoms of that disorder Project: I/LA25
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screening test in genotyping or strain typing, a method used to evaluate large populations for the presence of a specific genetic trait or microorganism Project: MM24
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screening test a test to systematically detect the presence or absence of a drug or a substance vs a predetermined threshold Project: C52, C63 NOTE: Screening is generally a qualitative procedure and results are reported as positive or negative relative to a stated cutoff value.
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screening test test that is generally used to evaluate the genetic status of an asymptomatic individual who is not necessarily at increased risk due to a positive family history Project: MM01
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screening test a test that provides presumptive results Project: M02, M07, VET01 NOTE: Additional testing is typically needed only for a specific result (eg, only when the screening test result is positive).
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screening window the time frame in which specimen collection is optimal to maximize the screening test’s positive predictive value and clinical utility Project: NBS03
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scripted interface a technology for interfacing point-of-care testing device data to a laboratory information system providing security features (eg, login, password) Project: POCT02 NOTE: A scripted interface emulates a human operator interacting with the user interface and is an alternative to electronic data interchange or Health Level 7 interfaces.
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secondary antibody an antibody that is labeled by fluorescent tag or biotin and binds to a primary antibody to allow its detection Project: H42, H43
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secondary antibody an antibody that recognizes and binds a primary antibody Project: I/LA30, ILA29
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secondary biomarker analyte or ratio of analytes that, if out of range in a particular disease, disease form, or phenotype, increases the specific risk when combined with an out-of-range primary biomarker result Alternate Term: secondary marker Project: NBS13, NBS09 Source: Newborn Screening Glossary NOTE 1: Analyte ratios are often considered secondary biomarkers in newborn screening; NOTE 2: A secondary biomarker alone might not indicate a specific risk for the disease or condition in question; NOTE 3: Secondary biomarkers are typically analyzed only when the primary biomarker(s) is out of range; NOTE 4: See biomarker and primary biomarker.
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secondary calibration standard See secondary standard Project: I/LA28
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secondary calibrator a reference material whose value is assigned using a reference (secondary or primary) procedure calibrated with a primary calibrator Project: EP32
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secondary calibrator a material or device having quantitative characteristics assigned based on a reference preparation or device, in which the analyte concentration or other quantity has been determined by a formal analytical procedure of stated reliability
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secondary container a vessel, into which the primary container is placed for transport within an institution that will contain a specimen if the primary container breaks or leaks in transit Alternate Term: secondary packaging Project: M29
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secondary markers markers that can be either analytes that are often abnormal in a particular condition or ratios of analytes that will be abnormal when their relative concentration is altered as a consequence of a metabolic block Project: NBS04 NOTE 1: These secondary markers can aid in the identification of disorders for which the primary marker may have a borderline value; NOTE 2: See biomarker.
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secondary packaging See secondary container Project: M29
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secondary patient identifiers unique identifiers used in addition to the primary patient identifiers. These can include the medical record number, telephone number, address, or photo ID, designated as acceptable by the organization Project: PRE01
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secondary reference laboratory (SRL) a laboratory in the National Glycohemoglobin Standardization Program (NGSP) laboratory network using an assay method that is certified as traceable to a primaary reference laboratory (PRL) using a designated comparison method (DCM); thus the SRL provides a link between routine clinical laboratory methods and the DCM Project: C44
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secondary reference measurement procedure measurement procedure that is calibrated by one or more primary calibrators (ISO 17593) Project: ISO 17593 NOTE: The measurement procedure for prothrombin time measurements is sometimes referred to as a "secondary standard procedure" (ISO 17593).
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secondary reference medium coded lot of Mueller-Hinton agar with performance characteristics that are similar to the primary reference medium, as determined by the protocol in CLSI document M6 Project: M6 NOTE 1: The main purpose of this medium is for use as a backup for the primary reference standard when its supply is threatened, or performance becomes unsatisfactory; NOTE 2: This medium is provided to manufacturers of dehydrated Mueller-Hinton agar for their use in evaluating production lots only when the primary reference medium is not available; NOTE 3: The stability testing is performed at the same intervals as for the primary reference medium; NOTE 4: The manufacturer of this lot is only known by the coding laboratory.
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secondary standard (calibrator) measurement standard established through calibration with respect to a primary measurement standard for a quantity of the same kind (JCGM 200:2012) Alternate Term: secondary measurement standard, secondary calibration standard Project: ISO IEC Guide 99, H58, H26, I/LA28 NOTE 1: Calibration may be obtained directly between a primary measurement standard and a secondary measurement standard, or involve an intermediate measuring system calibrated by the primary measurement standard and assigning a measurement result to the secondary measurement standard (JCGM 200:2012); NOTE 2: A measurement standard having its quantity value assigned by a ratio primary reference measurement procedure is a secondary measurement standard (JCGM 200:2012); NOTE 3: A substance or device that is based on a reference preparation or in which the analyte concentration or other quantity has been determined by an analytical procedure of stated reliability; NOTE 4: Calibrators are used to calibrate, graduate, or adjust a measurement.
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secondary standard (calibrator) a substance or device that is based on a reference preparation or in which the analyte concentration or other quantity has been determined by an analytical procedure of stated reliability Alternate Term: secondary calibration standard Project: H15 NOTE: Calibrators are used to calibrate, graduate, or adjust a measurement.
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secondary standard measurement standard whose quantity value and measurement uncertainty are assigned through calibration with respect to a primary measurement standard for a quantity of the same kind (ISO 15194) Alternate Term: secondary measurement standard Project: ISO 15194 NOTE 1: The relation can be obtained directly between the primary measurement standard and the secondary measurement standard, or involve an intermediate measuring system calibrated by the primary standard and assigning ameasurement result to the secondary standard (ISO 15194); EXAMPLE: NIST Standard Reference Material 1951b, Lipids in Frozen Human Serum is a secondary measurement standard that is calibrated using NIST Standard Reference Material 1911c, Cholesterol of known purity (ISO 15194); NOTE 2: "Measurement standard" includes "reference material" (ISO 15194); NOTE 3: Further explanation of the role of secondary measurement standards within a calibration hierarchy can be found in ISO 17511 and ISO 18153 (ISO 15194).
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secondary standard standard whose value is assigned by comparison with a primary standard of the same quantity (ISO 17511) Alternate Term: secondary measurement standard Project: ISO 17511, prEN 12287, H57 NOTE: The word “measurement” has been included in the term here for consistency (prEN 12287:1998).
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secondary standard method prothrombin time test system which is calibrated against a primary standard and used in the calibration of a PT test Project: ISO 17593 (January 2002)
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secondary target in newborn screening, a condition that does not meet the requirements of a primary target condition, but that might be identified as a by-product of screening for a primary target condition Project: NBS06
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secondary target disease (for newborn screening) a disease form or a specific phenotype of the primary target disease or a different disease altogether that might be detected during the process of screening for a primary target disease Project: NBS09, NBS13 Source: Newborn Screening Glossary NOTE 1: Secondary target diseases typically do not meet all of the criteria for a primary target disease; NOTE 2: Secondary target diseases often have clinical manifestations that, if diagnosed, can be ameliorated with treatment; however, it is not the aim of the newborn screening program to detect these diseases; NOTE 3: Target diseases can also be referred to as “target conditions” or “target disorders”; NOTE 4: See primary target disease.
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secondary tube a tube used to contain the resultant plasma/serum yielded by the centrifugation of a primary additive/serum tube containing the patient sample
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second-tier screen (for newborn screening) additional assay, physiological measurement, or assessment, performed as a second step in a laboratory screening algorithm on a subset of newborns, that uses the initial screening specimen (ie, specimen re-collection not necessary) when first-tier testing results are out of range Alternate Term: second-tier screening; second-tier testing Project: NBS03, NBS04, NBS07, NBS08, NBS13, NBS09, NBS10 Source: Newborn Screening Glossary NOTE 1: A second-tier screen generally uses or assesses a different method, technology, and/or biomarker than the first-tier screen and often defines the final, reportable result; NOTE 2: Because of its higher specificity, a second-tier screen is typically used to reduce the number of false-positive screening results; NOTE 3: Also called “reflex testing”; NOTE 4: See laboratory screening algorithm, screening test, first-tier screen, and third-tier screen.
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second-tier testing the subsequent testing that occurs after primary testing, either because the second test is necessary for complete reporting of the primary test result, or performing the secondary test (ie, the reflex test) is the standard of care Project: GP49
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Secure Hash Standard the US government standard that specifies the Secure Hash Algorithm, a cryptographic hash function that produces a 160-bit output (hash result) for input data of any length < 2**64 bits.1 (RFC 2828) Project: AUTO09
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sediment the formed elements of urine that are concentrated by centrifugation or detectable with flow-through cytometers in a whole urine sample Project: GP16 NOTE: Elements include cells (leukocytes, renal tubular, etc.), casts (hyaline, waxy, etc.), crystals (triple phosphate, cystine, etc.), microorganisms (bacteria, yeast, etc.), and others.
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segment a logical grouping of data fields Project: AUTO02 NOTE: Segments of a message may be required or optional. They may occur only once in a message or they may be allowed to repeat.
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select agent biological agents or toxins that have the ability to cause a severe threat to human, animal, or plant health Project: GP36 NOTE: The possession and use of these agents are closely regulated and restricted by several federal agencies, including the US Department of Health and Human Services, Centers for Disease Control and Prevention, and US Department of Agriculture. Federal regulations that apply to these agents or toxins include: US Department of Health and Human Services and US Department of Agriculture Select Agents and Toxins, 7 CFR Part 331, 9 CFR Part 121, 42 CFR Part 7; see the National Select Agent Registry.
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select agent agents and toxins determined by the US Department of Health and Human Services or US Department of Agriculture Animal and Plant Health Inspection Service to have the potential to pose a severe threat to human, animal, and/or public health Alternate Term: biological select agents and toxins Project: M29 NOTE: A discussion and list of these agents are accessible on the National Select Agent Registry website.
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select agents list developed by the Department of Health and Human Services of biological agents and toxins that could cause a severe impact on life and safety Project: GP05 NOTE: The list can be found at www.selectagents.gov (eg, tularemia, anthrax).
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select agents agents and toxins determined by the US Department of Health and Human Services and US Department of Agriculture to have the potential to pose a severe threat to human, animal, and/or public health Project: QMS28 NOTE: A list of these agents and toxins is available on the Federal Select Agent Program website (https://www.selectagents.gov/sat/list.htm)
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selected ion monitoring operation of a mass spectrometer in which the abundances of several ions of specific m/z values are recorded rather than the entire mass spectrum (IUPAC 2006) Project: C43
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selected ion monitoring a mode of operation where the ion current(s) of one (or several) distinct (selected) m/z value(s), rather than the entire mass spectrum, is recorded Alternate Term: selected ion recording; SIR Project: C50 NOTE: The terms multiple ion monitoring, multiple ion detection, multiple peak monitoring, and mass fragmentography are not recommended.
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selected ion monitoring mode of operation for a tandem mass spectrometer in which one, or multiple, precursor(s) to product transition(s) is monitored (terminology commonly used interchangeably with multiple reaction monitoring) Project: C63
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selected method a procedure, the reliability of which has been validated by a collaborative study and which is recommended by a defined authority for routine use in a laboratory analysis, having been selected on the grounds of its accuracy and precision, the intended scope of the test, economy of labor and materials, and ease of operation Project: H15
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selected method a method approved by a defined authority as being suitable for routine use, taking account of the limits of its bias and imprecision in the context of its intended (clinical) purpose, economy of materials and labor, ease of performance, and safety; its validity must be verified by comparability with a reference method Alternate Term: selected procedure Project: H02 NOTE: A reference method may be used as a selected method in some instances; when a reference method is not available, or is not practical, in order to ensure harmonization, one selected (routine) method may be designated as a standardized method (procedure). For this, the equipment, reagents, and test procedure must be clearly and exactly specified (modified from ICSH).
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selected reaction monitoring the mode of operation of a tandem mass spectrometer in which a specific precursor-product relationship (selected), or several precursor-product relationships (multiple), are examined Project: C50, C57 NOTE 1: Distinct m/z values, rather than the entire mass spectrum, are recorded; NOTE 2: This mode of operation offers enhanced selectivity, and consequently, an improved limit of detection when performed on a tandem quadrupole mass spectrometer; NOTE 3: This mode of operation offers enhanced selectivity and consequently an improved limit of detection. The mode of operation is also sometimes referred to as multiple reaction monitoring although this term is not preferred.
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selected reaction monitoring data acquired from specific product ions corresponding to m/z selected precursor ions recorded via two or more stages of mass spectrometry. Selected reaction monitoring can be performed as tandem mass spectrometry in time or tandem mass spectrometry in space (IUPAC 2006) Project: C43
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selected reaction monitoring the mode of operation of a tandem mass spectrometer in which a specific precursor-product transition (selected), or several precursor-product transitions (multiple), are monitored Project: NBS07, NBS04, NBS09 NOTE 1: Distinct m/z values, rather than the entire mass spectrum, are monitored; NOTE 2: This mode of operation offers enhanced sensitivity and consequently an improved lower limit of detection; NOTE 3: This mode of operation is also sometimes referred to as “multiple reaction monitoring,” although this term is not preferred.
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selective reporting strategy of reporting of certain antimicrobial susceptibility test results on an individual patient’s isolate based on defined criteria, such as organism identification, body site, resistance mechanism, and overall susceptibility profile Project: M39
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selectivity (of a measuring system) property of a measuring system, used with a specified measurement procedure, whereby it provides measured quantity values for one or more measurands such that the values of each measurand are independent of other measurands or other quantities in the phenomenon, body, or substance being investigated (JCGM 200:2012) Alternate Term: selectivity of a measuring system Project: ISO IEC Guide 99, C58, C51, EP07, EP30 EXAMPLE 1: Capability of a measuring system including a mass spectrometer to measure the ion current ratio generated by two specified compounds without disturbance by other specified sources of electric current (JCGM 200:2012); EXAMPLE 2: Capability of a measuring system to measure the power of a signal component at a given frequency without being disturbed by signal components or other signals at other frequencies (JCGM 200:2012); EXAMPLE 3: Capability of a receiver to discriminate between a wanted signal and unwanted signals, often having frequencies slightly different from the frequency of the wanted signal (JCGM 200:2012); EXAMPLE 4: Capability of a measuring system for ionizing radiation to respond to a given radiation to be measured in the presence of concomitant radiation (JCGM 200:2012); EXAMPLE 5: Capability of a measuring system to measure the amount-of-substance concentration of creatinine in blood plasma by a Jaffé procedure without being influenced by the glucose, urate, ketone, and protein concentrations (JCGM 200:2012); EXAMPLE 6: Capability of a mass spectrometer to measure the amount-of-substance abundance of the 28Si isotope and of the 30Si isotope in silicon from a geological deposit without influence between the two, or from the 29Si isotope (JCGM 200:2012); NOTE 1: In physics, there is only one measurand; the other quantities are of the same kind as the measurand, and they are input quantities to the measuring system (JCGM 200:2012); NOTE 2: In chemistry, the measured quantities often involve different components in the system undergoing measurement and these quantities are not necessarily of the same kind (JCGM 200:2012); NOTE 3: In chemistry, selectivity of a measuring system is usually obtained for quantities with selected components in concentrations within stated intervals (JCGM 200:2012); NOTE 4: Selectivity as used in physics (see NOTE 1) is a concept close to specificity as it is sometimes used in chemistry (JCGM 200:2012); NOTE 5: Selectivity is a concept similar to analytical specificity; NOTE 6: The property of a measuring instrument being selective to only one measurand in a sample should not be called “specificity,” to avoid ambiguity with immunological, clinical, or diagnostic specificity.
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selectivity property of a measurement procedure that relates to the extent to which measured quantity values for one or more measurands are independent of other measurands or other quantities in the substance being investigated (ISO 17511) Project: EP32
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selectivity (of a measurement procedure) ability to accurately measure an analyte in the presence of interferences that may be expected to be present in the sample matrix Project: C50 NOTE 1: It is recommend by the International Union of Pure and Applied Chemistry that the term selectivity be used to describe the ability to detect an analyte without interference, rather than analytic specificity, as selectivity is not as absolute as the term specific; NOTE 2: The term specific generally refers to a method that produces a response derived only from a single analyte; whereas the term selective refers to a method that provides responses for a number of analytes that may or may not be distinguished or distinguishable from each other. If the response is distinguished from all other responses, the method is said to be “selective.” Because there are very few methods in mass spectrometry that respond to only one analyte, the term selectivity is usually more appropriate; NOTE 3: See specificity (analytical).
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selectivity ability of an analytical method to differentiate and measure the analyte in the presence of interfering substances in the biological matrix (nonspecific interference) Project: H62 NOTE 1: Ability of the assay to accurately measure the analyte unequivocally in the presence of interferences or structurally unrelated components that may be expected to be present in the intended matrix; NOTE 2: Selectivity of a measuring system is the property of a measuring system, used with a specified measurement procedure, whereby it provides measured quantity values for one or more measurands such that the values of each measurand are independent of other measurands or other quantities in the phenomenon, body, or substance being investigated; NOTE 3: As related to flow cytometers, selectivity is used by instruments that have optical filters with spectral compensation in an attempt to compensate for the spectral overlap of autofluorescence or other fluorescent probes; NOTE 4: As related to flow cytometric methods, selectivity is used by the assay design as described in H62. NOTE 5: Selectivity is a concept similar to analytical specificity; NOTE 6: See specificity, analytical.
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selectivity of a measuring system See selectivity Alternate Term: selectivity Project: C51
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self-calibrated the ability for the test system to calibrate itself automatically without operator intervention Project: POCT07
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self-testing performance of IVD examinations in the home or other environments by a lay person who will relate the examination result to himself or herself
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self-testing examination performed by a layperson to evaluate an individual's health status (ISO 18113-1)
Project: ISO 18113-1 NOTE 1: Typically performed in a home or other environment outside a healthcare institution without supervision by a healthcare professional (ISO 18113-1); NOTE 2: Adapted from the definition of “device for self-testing” in Directive 98/79/EC of the European Parliament and the Council of 27 October 1998 on in vitrodiagnostic medical devices, Official Journal of the European Union L331, 7 December 1998 (ISO 18113-1).
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semiautomated a characterization applied to an instrument or system in which some of the steps in the analytical process are mechanized but others require operator intervention (US CFR493 February 28, 1992)
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semiautomated MIS microbial identification system in which at least one step (eg, inoculation, incubation, result interpretation) is performed by an instrument Project: M50
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semiautomated system a system in which some but not all of the following are mechanized: sample and reagent uptake, sample and reagent interaction, chemical or biological analysis, reaction measurement, result interpretation, and result report Project: I/LA33
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seminar meeting or conference intended to orient participants to authorities, strategies, plans, policies, procedures, protocols, resources, concepts, and/or ideas Project: GP36 NOTE: Seminars provide a good starting point for jurisdictions that are developing or making major changes to their plans and procedures.
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semiquantitative a test that has a dose-response gradient that may be included in the reported result but that has no authorative calibration scale to determine inaccuracy and imprecision Project: I/LA02, I/LA33, EP26 NOTE: A test yielding results in an approximate range of values (eg, trace, moderate).
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semiquantitative tests that yield results in an approximate range of values (eg, trace, moderate) Project: POCT04
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semiquantitative an estimated value of a measurand that cannot be directly assessed, for which no authoritative calibration scale exists to determine inaccuracy and imprecision Project: H62 NOTE 1: Tests with an instrumental readout of quantification where the instrument scale cannot be referenced to an authoritative calibration scale or standard reference material; NOTE 2: Also includes tests that yield ordinal results expressed in an approximate range of values (eg, neg, +, ++, +++); NOTE 3: See quasiquantitative and ordinal.
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semiquantitative assay a semiquantitative assay system provides an additional option over the qualitative assay in terms of defining the magnitude of the response. The variations in the positive signal detected by the assay are commonly presented in terms of a series of increasing grades or classes (eg, I to VI, low to high); in arbitrarily defined units per milliliter determined relative to a supplier-specific heterologous dose-response curve or an end-point dilution at which the assay signal becomes negative (eg, titer); or in comparison to a qualitative grading scheme (eg, color chart) Project: I/LA20 NOTE: Allergen-specific immunoglobulin E assays that use normalized counts generated in two-point calibrated, modified, or alternative scoring systems are considered semiquantitative assays unless demonstrated otherwise.
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semiquantitative tests those that yield results in an approximate range of values (ie, trace, moderate) Project: AST02, HS02
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sender the device that has a message to send and initiates the transmission process Project: LIS01
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senescent cell culture culture with reduced or arrested metabolic and growth activity Project: M41
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sense strand the strand of a duplex DNA that has the same nucleotide sequence as messenger RNA except that thymine substitutes in DNA for uracil in RNA Project: MM10, MM12 NOTE: The sense strand is also called the “coding” strand. The other strand, which is the actual template for messenger RNA synthesis, is the anticoding or antisense strand.
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sensing volume in fluorometry, the intersection of the illumination volume (created by the incident light) and the detection volume (determined by the optical detection path) Project: I/LA24 NOTE: Only fluorochrome molecules in the sensing volume can contribute to the fluorescence signal.
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sensitive information and data protected health information, personally identifiable information, proprietary software source code or business logic, configuration parameters, user credentials, cryptographic keys, quality control, and calibration results Project: AUTO11
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sensitivity (of a measuring system) quotient of the change in an indication of a measuring system and the corresponding change in a value of a quantity being measured (JCGM 200:2012) Project: JCGM 200:2012, ILA29, H58, C34, C43, I/LA28, H02, C58, MM19, MM01, MM20, MM14, C40, I/LA26, MM22, POCT14, H60, C62, C57, MM03, POCT06, H48, POCT04, QMS24, NBS04, C49, MM24 NOTE 1: Sensitivity of a measuring system can depend on the value of the quantity being measured (JCGM 200:2012); NOTE 2: The change considered in a value of a quantity being measured must be large compared with the resolution (JCGM 200:2012); NOTE 3: The sensitivity depends on the imprecision of the measurements of the sample; NOTE 4: In the context of NBS04, sensitivity refers to the signal intensity of the analyte being measured; NOTE 5: From predictive value theory, the proportion of subjects with a condition who have a positive test; NOTE 6: The term “sensitivity” is used mainly for “clinical sensitivity/diagnostic sensitivity”; NOTE 7: The lower limit of detection of a nucleic acid sequencing method; NOTE 8: In the context of quality control, the power of error detection of a quality control system; NOTE 9: In qualitative testing, the test method’s ability to obtain positive results in concordance with positive results obtained by the reference method.
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sensitivity 1) change in the response of a measuring instrument divided by the corresponding change in the stimulus (VIM93); 2) in predictive value theory, the proportion of test results that are positive when the reference results are positive (true positives/true positives + false negatives) Alternate Term: analytical sensitivity, diagnostic sensitivity Project: H44, I/LA24, I/LA23, H49, H20, H42, H43, H57 NOTE 1: The sensitivity may depend on the value of the stimulus (VIM93); NOTE 2: The sensitivity depends on the imprecision of the measurements of the sample (NRSCL8); NOTE 3: In the context of quality control, the power of error detection of a quality control system; NOTE 4: In Qualitative Testing, the test method’s ability to obtain positive results in concordance with positive results obtained by the reference method; NOTE 5: If the true sensitivity of a device is better than the reference method, its apparent specificity will be less and the level of apparent false-positive results will be greater; NOTE 6: In CLSI documents H42 and H43, sensitivity is the ability to distinguish signals of interest from background optical or electronic “noise” or biological signals, such as those due to autofluorescence or nonspecific reagent binding.
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sensitivity See analytical sensitivity, clinical sensitivity, and seroconversion sensitivity Project: M53
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sensitivity (analytical) 1) the sensitivity of a method as the slope of the calibration curve and the ability of an analytical procedure to produce a change in the signal for a defined change of the quantity; 2) change in the response of the measuring system divided by the corresponding change in the quantity or property of the analyte Project: I/LA34 NOTE: This term should not be used synonymously with detection limit.
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sensitivity (assay) lowest analyte concentration reliably determined as nonzero with a minimum reliably detectable level Project: POCT04
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sensitivity (clinical) the ability of a test to give a positive result for patients who have the disease or condition for which they are being tested Project: POCT04 NOTE: It is measured as the ratio of positive tests to the total number of tests in those who have the disease and is often expressed as a percentage.
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sensitivity (diagnostic) the proportion of patients with a well-defined clinical disorder whose test values are positive or exceed a defined decision limit (ie, a positive result and identification of the patients who have a disease) Project: H20 NOTE 1: The clinical disorder must be defined by criteria independent of the test under consideration; NOTE 2: The term diagnostic sensitivity (Europe) is equivalent to clinical sensitivity (United States); NOTE 3: In predictive value theory, clinical sensitivity is mathematically defined as the proportion of test results that are positive when the reference results are positive (total positives/total positives + false negatives).
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sensitivity the ability to distinguish signals of interest from background optical or electronic “noise” or biological signals, such as those due to autofluorescence or nonspecific reagent binding Project: H52
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sensitivity synonym of detection rate Project: I/LA25 NOTE: An advantage of the term detection rate over sensitivity is that it avoids confusion because sensitivity has a different meaning in analytical biochemistry. In cancer screening, the cancer “detection rate” can have a different meaning, namely the prevalence of detected cancers at a screening examination, perhaps better described as the screen-positive cancer prevalence instead of the proportion of all individuals with cancer who have positive results.
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sensitivity (diagnostic) the ability of a test to give a positive result for subjects who have the disease or condition for which they are being tested Project: EP24 NOTE 1: It is measured as the ratio of positive test results in those who have the condition to the total number who have the condition, and is often expressed as a percentage; NOTE 2: Formerly, the term “clinical sensitivity” was used in CLSI documents.
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sensitivity the ability of a test to detect the disease or condition it is intended to find Project: POCT08, POCT15 NOTE 1: “Analytical sensitivity” is the smallest amount of the target material the test can detect; NOTE 2: “Diagnostic sensitivity” (also referred to as “clinical sensitivity”) is the percentage of persons with the disease who have a positive test; NOTE 3: A highly sensitive test is effective at finding people affected by the disease or condition but may (depending on its specificity) also detect many people who do not have the disease.
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sensitivity, analytical the lowest amount of a substance in a biological specimen that is detectable in an assay system Project: H62 NOTE 1: ”Analytical sensitivity” is an older term historically equated with the detection limit in the medical laboratory and is replaced with “detection capability”; NOTE 2: Amount of measurand being detected by the measurement procedure at a given detection frequency; NOTE 3: Analytical sensitivity should not be confused with clinical sensitivity; NOTE 4: The ability of a test to detect a target measurand, which is usually expressed as the minimum detectable concentration of the measurand; NOTE 5: In qualitative testing, analytical sensitivity is defined as the test method’s ability to obtain positive results in concordance with the positive results obtained by the reference or comparative method; NOTE 6: See detection capability.
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sensitivity, clinical ability of a test to detect the disease or condition it is intended to find Project: H62 NOTE 1: Also referred to as “diagnostic sensitivity” (percentage of persons with the disease who have a positive test); NOTE 2: A highly sensitive test is effective at finding individuals affected by the disease or condition but may (depending on its specificity) also detect many others who do not have the disease; NOTE 3: It is measured as the ratio of positive test results in those who have the condition to the total number who have the condition and is often expressed as a percentage; NOTE 4: The condition or characteristic of interest must be defined by criteria independent of the test under consideration.
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sensitization binding of an antibody or complement components to a red cell in the first stage of red cell agglutination with no visible detection of agglutination Project: I/LA33
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sensor element of a measuring system that is directly affected by a phenomenon, body, or substance carrying a quantity to be measured (JCGM 200:2008) Project: ISO IEC Guide 99, POCT05 EXAMPLES: Sensing coil of a platinum resistance thermometer, rotor of a turbine flow meter, Bourdon tube of a pressure gauge, float of a level-measuring instrument, photocell of a spectrometer, thermotropic liquid crystal, which changes color as a function of temperature (JCGM 200:2012); NOTE: In some fields, the term “detector” is used for this concept (JCGM 200:2012).
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sensor element of a measuring instrument or measuring chain that is directly affected by the measurand (VIM93); EXAMPLES a) measuring junction of a thermoelectric thermometer; b) rotor of a turbine flow meter; c) Bourdon tube of a pressure gauge; d) float of a level-measuring instrument; e) photocell of a spectrophotometer (VIM93) Project: VIM93 NOTE In some fields, the term "detector" is used for this concept.
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sensor the part of the pulse oximeter applied to the patient that contains the light source(s) and detector(s) Project: POCT11 NOTE: This term is used interchangeably with the term “probe.”
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sensor drift a progressive and gradual change in deviation between sensor reading and reference value over time that, in some systems, is corrected with recalibration Project: POCT05 NOTE: Sensor drift is typically caused by a change in the sensing system or changes at the interface between the sensing surface and the biological tissue.
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sensor output signal the output signal from a continuous glucose monitoring sensor that contains both glucose-specific information and noise Project: POCT05 NOTE 1: Noise is a change in the output signal unrelated to a change in the glucose concentration. The glucose-specific signal and the noise signal change independently over time; NOTE 2: Sensor performance is modeled under steady state in vitro and in vivo conditions to develop an algorithm that distinguishes the glucose-specific signal from the noise and the drift; NOTE 3: Sensor drift is a progressive and gradual change in deviation between sensor reading and reference value over time. Drift is typically caused by a change in the sensing system or changes at the interface between the sensing surface and the biological tissue; NOTE 4: Drift that occurs slowly, in a characteristic fashion, can be managed by recalibration of the in vivo sensor to a reference blood glucose measurement; NOTE 5: Chemical and physical changes external to the sensor (tissue fluid interface with sensor) and internal to the sensor (transducer and electrode foiling) cause a change in the output signal unrelated to glucose. The sensor noise level is affected by the bandwidth of the sensor system and therefore, noise measurements and specifications should include references to the system bandwidth. Lowering the system bandwidth tends to decrease the noise level at the cost of a slower system response; NOTE 6: The output signal from two or more continuous glucose monitor sensors (in vivo array) can be analyzed to optimize glucose measurement accuracy and precision related to direction of change, rate of change, and absolute value. Processing multiple output signals can decrease noise and compensate for drift.
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sensor run-in time the time from sensor insertion until initial calibration or display of the first glucose reading Alternate Term: sensor warm-up time Project: POCT05 NOTE 1: The run-in time is caused by unstable chemical and/or physical conditions around the sensor and changes internal to the sensor. Subcutaneous and transcutaneous continuous glucose monitoring sensors damage blood vessels, extracellular matrix, and cells during subcutaneous tissue insertion. The coagulation, immune, and inflammatory systems may be activated. The in vivo sensor exhibits frequent changes in noise and drift; NOTE 2: When calibration is needed, manufacturers have to take appropriate measures to make sure sensor signal is stable enough for the initial calibration and/or recalibration using an appropriate sample.
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sensor stability consistency in the accuracy of the sensor during its use life
Project: POCT05
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sensor system the integrated set of hardware and software components that provides context and functionality to the sensor
Project: POCT05
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sensor use life the time interval from sensor insertion until the sensor fails to perform within accuracy specifications. This interval can be shorter, longer, or the same as the labeled sensor use life (wear period) and can vary from sensor to sensor Project: POCT05
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sentinel event unexpected occurrence involving death or serious physical or psychological injury, or the risk thereof Project: POCT07 NOTE 1: Serious injury specifically includes loss of limb or function; NOTE 2: The phrase “or the risk thereof” includes any process variation for which a recurrence would carry a significant chance of a serious adverse outcome; NOTE 3: Such events are called “sentinel” because they signal the need for immediate investigation and response.
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separated serum serum or plasma that has been completely separated from any contact with cells or a clot Alternate Term: separated plasma NOTE 1: The serum or plasma has either been removed, by pipette, from the cells or contact has been interrupted by a chemical/physical barrier through the use of a serum/plasma separator device; NOTE 2: The separated serum/plasma should be visually free of erythrocytes; however, 0.1% to 1% intact cells do not contribute to a hemolysis effect.
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sepsis life-threatening organ dysfunction caused by a dysregulated host response to infection Project: M47
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septate hyphae with cross-walls separating the cells Project: M54
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septic episode an episode of sepsis, for which a blood culture or blood culture series is obtained Project: M47
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septic shock sepsis with arterial hypotension despite adequate fluid resuscitation
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sequence the order of nucleotides (adenine, cytosine, guanine, thymine, or uracil) in a strand of DNA or RNA, or the order of amino acids in a protein Project: MM02, MM10, MM18, MM24
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sequence the order of nucleotides (ie, adenine, cytosine, guanine, thymine, or uracil) in a strand of DNA or RNA Project: MM22, MM09
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sequence the order of nucleotides (base sequence) in a DNA or RNA molecule, or the order of amino acids in a protein Project: MM19
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sequencing a technology that is used to determine the order of nucleotides (base sequence) in a DNA or RNA molecule, or the order of amino acids in a protein Project: MM19
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sequencing methods and procedures that determine the sequence of amino acids (in a protein) or nucleotide residues (in DNA or RNA) Project: MM22, MM24
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sequestered lot large quantities of a single lot number secured for an organization in an arrangement with a reagent manufacturer Project: QMS21 NOTE: In this type of arrangement, the supplier agrees to hold a specific lot number and volume of a particular product. In return, the laboratory commits to purchase the entire sequestered product over a period of time.
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serial dilution the progressive dilution of a material or substance in predetermined ratios Project: POL1/2
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series a delineated set of measured samples Project: C51 NOTE: The series can be defined differently depending on the measurement system, eg, between calibrations, or reagent lots, within a defined time interval.
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serious injury an injury that is life-threatening, results in permanent impairment of a body function or permanent damage to a body structure, or necessitates medical or surgical intervention to preclude permanent impairment. Permanent means irreversible impairment or damage to a body structure or function, excluding trivial impairment or damage Project: EP19 NOTE: It could also mean when medical intervention is not taken if appropriate due to the reporting of an erroneous result.
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seroconversion the conversion of a individual patient’s serum from negative to positive, or vice-versa, in a given test for antibodies to the infectious agent in question Project: ILA18
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seroconversion sensitivity the time point after infection at which an assay detects any class of specific HIV antibody Project: M53
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seroconversion window period the duration of the period from the time of HIV infection until first detection of a specific HIV antibody response that includes the acute and eclipse infection phase (acute + eclipse) Project: M53
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serotonin an amino acid-derived substance from phenylalanine Alternate Term: 5-hydroxytryptamine Project: H58
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serum the liquid remaining after untreated whole blood has coagulated Project: C56, POCT04
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serum bactericidal test a simple variation of the broth dilution (antimicrobial susceptibility) test, with serial dilutions of a sample of serum from the patient being used instead of concentrations of antimicrobial agents Project: M21
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serum bactericidal titer the highest titer of a patient’s serum during antimicrobial therapy that kills 99.9% of the patient’s bacterial cells after a fixed length of time Project: M21
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serum binding capacity the reciprocal of the free thyroid hormone fraction, which is proportional to the number of free hormone binding sites and binding affinity Project: C45
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serum inhibitory titer the highest titer of a patient’s serum capable of inhibiting visible growth of the patient’s pathogen during antimicrobial therapy Project: M21
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server a computer that can be accessed remotely that handles large numbers of data communications over a network Project: POCT02
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service activities and steps related to performing inpatient pharmacy functions
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service the result generated by activities at the interface between the provider and the customer and by provider’s internal activities to meet the customer needs (ISO 8402, 1.5)
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service within the scope of QMS23, the act or process of performing maintenance or other actions on laboratory equipment Project: QMS23
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service access point an Infrared Data Association connection service endpoint provided by the IrLMP-IAS information access service directory Project: POCT01 NOTE: Also termed link service access point.
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service envelope in Automation, the space around the transportation system and instruments that may be accessed periodically for maintenance or repair of equipment Project: AUTO01, AUTO02 NOTE: A transportation system and analytic instruments should not have mutually impinging service envelopes.
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session a total unit of communication activity, used in CLSI standard LIS01 to indicate the events starting with the establishment phase and ending with the termination phase, as described in subsequent sections Project: LIS01
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set-point the level (ie, measurand concentration) at which an analyzer is calibrated Project: H26
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set-point the stable level of viral copies in blood established after seroconversion
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sever sepsis sepsis associated with organ dysfunction, hypoperfusion, or hypotension
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severe combined immunodeficiency a congenital primary immune deficiency with severe impairment of cellular and humoral immune responses due to a profound deficiency in the development of autologous T-cells and characterized by a significantly decreased number of naive T-cells and T-cell receptor excision circles, and a decrease in proliferative responses to T-cell mitogens Project: NBS06 NOTE: The majority of typical severe combined immunodeficiency cases can be demonstrated to be caused by defect(s) in any one of over 20 known genes, but some cases do not have a defined genotype, and identification of a mutation is not required for diagnosis or treatment.
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severity measure of the possible consequences of a hazard (ISO 14971) Project: ISO 14971, EP18, EP23
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severity consequences of a failure mode NOTE: Severity considers the worst potential consequence of a failure, determined by the degree of injury, property damage, or system damage that could ultimately occur.(MIL-STD-1629A. Procedures for Performing a Failure Mode, Effects and Criticality Analysis. 24 November 1980.)
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severity of harm refers to either the extent of an adverse outcome for a patient or an event that negatively affects the patient’s health and welfare Project: QMS17 NOTE: Severity can also be associated with extended patient stay or other financial effects on the organization.
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sex-linked recessive synonymous with X-linked recessive, a mode of inheritance in which a mutation in a gene on the X chromosome causes the phenotype to be expressed in males who are hemizygous for the gene mutation (ie, males with only one X chromosome) and in females who are homozygous for the gene mutation (ie, females with a copy of a gene mutation on each of their two X chromosomes). Carrier females who have only one copy of a mutation do not usually express the phenotype, although differences in X-chromosome inactivation can lead to varying degrees of clinical expression in carrier females
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SHA-1 Secure Hash Algorithm. See Secure Hash Standard (RFC 2828) Project: AUTO09
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shape change sphering of disc-shaped platelets after the binding of a platelet agonist (eg, adenosine diphosphate, collagen, thrombin) that may be detected by a decrease in light transmission Project: H58
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sharps discarded laboratory or medical articles that may cause puncture or cuts, including, but not limited to, all needles, syringes, lancets, pen needles, Pasteur pipettes, broken medical or laboratory glassware/plasticware, scalpel blades, suture needles, dental wires, and disposable razors used in connection with a medical or laboratory procedure Project: M29
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sharps container a container approved for the containment and transport of contaminated sharps Project: M29
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sharps with engineered sharps injury protection a nonneedle sharp or a needle device used for withdrawing body fluids, accessing a vein or artery, or administering medications or other fluids, with a built-in safety feature or mechanism that effectively reduces the risk of an exposure incident Project: M29, X03
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shear the consequence of the relative parallel motion of fluid planes during flow within a vessel or tube Project: H58 NOTE: The velocity of fluid is higher in the middle of a tube/vessel and decreases towards the walls. The velocity gradient between the parallel fluid planes is called shear rate. The unit for shear rate is expressed as inverse second s-1. In this document, high shear is generally considered to be greater than 1000 s-1 as it pertains to high shear instrumentation. Low shear is generally considered to be less than 1000 s-1 as it pertains to low shear instrumentation.
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sheet vinyl flooring supplied in large sheets to minimize seams in the floor
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shelf life time interval during which the producer of the certified reference material warrants its stability Project: EP30 NOTE: The shelf life is equivalent to the period of validity of the certificate.
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shelf life period of time until the expiry date during which a product in its original packaging maintains its stability under the storage conditions specified by the manufacturer (adapted from EN 375:2001, §3.16) Project: EP25 NOTE 1: Stability and expiry date are related concepts; NOTE 2: The manufacturer is responsible for determining the period of time and the conditions for which stability claims are established; NOTE 3: The manufacturer should consider stability at a given temperature as the last time point at which acceptance criteria have been met that precedes two consecutive time points at which failures have occurred. This can minimize false conclusions due to a test failure that is not a function of product instability.
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shelf life period of time that an IVD medical device maintains its performance characteristics Project: ISO CD 18113-1, ISO CD 18113-2, ISO CD 18113-3 NOTE: Stability and expiry date are related concepts. See the definitions of stability, §3.60 and expiry date, §3.15.
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shelf-life period of time until the expiry date during which an in vitro diagnostic reagent in its original packaging maintains its stability under the storage conditions specified by the manufacturer (ISO 18113-1)
Project: ISO 18113-1, EP39 NOTE 1: Stability and expiry date are related concepts (ISO 18113-1); NOTE 2: Adapted from EN 375:2001, definition 3.16 (ISO 18113-1).
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shelf-life the time period until the expiration date or the period during which a device remains suitable for the intended use, whichever is shorter
Project: POCT05
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shell vial flat-bottomed glass vial suitable for holding a coverslip on which the cell monolayer develops Project: M41
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shelter-in-place process for taking immediate shelter in a location readily accessible to the affected individual by sealing a single area from outside contaminants and shutting off all heating, ventilation, and air conditioning systems Project: GP36 NOTE: These actions would generally be taken after a chemical accident or terrorist attack.
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shift In plots of daily QC points, an abrupt change or deviation in those values from one day to the next Project: AST02
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shift-JIS-code the Japan Industry Standard multibyte encoding system Project: AUTO01, AUTO02, AUTO03 NOTE: The codes are numerically shifted from the codes used by the JIS standard X0208, hence the name.
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shipper anyone who ships goods by a commercial carrier (usually an employee of a company or health care facility [ie, laboratory staff member, contracted courier, and physician]), offers goods for transport to a member of International Air Transport Association, or anyone who completes and signs the Shipper’s Declaration for Dangerous Goods Project: M29
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shipping conditions environmental parameters, established by manufacturer, describing how a product is to be shipped Project: M50
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shipping study study/analysis/evaluation, performed during product development, assuring that a product can be shipped without deterioration that negatively impacts product performance under different adverse temperature conditions Project: M50
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short tandem repeat also known as microsatellite repeats; consist of di-, tri-, tetra-, or pentanucleotide tandem repeats Project: MM01 NOTE: A specific short tandem repeat locus can be highly polymorphic, having numerous alleles that differ by the number of repeat units arranged in tandem.
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short tandem repeat repetitive segments of DNA two to five nucleotides in length Project: MM10, MM12, MM24 NOTE 1: A specific locus can be highly polymorphic, having numerous alleles which differ in the number of repeat units; NOTE 2: Also known as microsatellite repeats.
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short-term follow-up steps taken to ensure a final screening outcome for newborns with actionable screening results Project: NBS02, NBS03, NBS05, NBS08, NBS09, NBS10 Source: Newborn Screening Glossary EXAMPLES: Request for a repeat specimen and confirmation of its receipt, notification of a screen-positive result, and the steps taken to obtain a final screening outcome; NOTE: See long-term follow-up, repeat screening (requested), and screen positive.
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shoulder (re: histogram peaks) a slight change in the architecture of the peak seen when doing flow cytometry human leukocyte antigen antibody screening Project: ILA29 NOTE: The peak will appear to have a slight shift to the right that appears as a shoulder or distortion of the symmetry of the peak and may be due to weak antibody.
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shunt fraction (Qsp/Qt) the fraction of venous blood that remains unoxygenated after traveling from the right side of the heart to the left side of the heart. See also Gas exchange indices Project: C12 NOTE: The nonstandard symbol “Q” represents blood flow; “sp” and “t” represent the shunted blood and total blood flows, respectively.
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SI units See International System of Units
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sickle cell anemia a form of sickle cell disease, resulting from clinically significant homozygous hemoglobin S or compound heterozygous hemoglobin S/β0 thalassemia, in which only hemoglobin S is produced Project: NBS08
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sickle cell disease a group of clinically significant conditions resulting from hemoglobin (Hb) S inherited in the homozygous state or in combination with either another variant (eg, Hb C, Hb D, Hb E, Hb O-Arab) or a β thalassemia mutation Project: NBS08
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sickle cell trait term commonly used to refer to persons who are carriers of the sickle cell gene Project: NBS08
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sickling hemoglobin any hemoglobin that causes erythrocytes to form sickle-like shapes under conditions of low oxygen tension NOTE: Currently, known sickling hemoglobins are: HbS, HbC-Harlem, HbS-Travis, and HbC-Ziguinchor.
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side scatter (right angle [90o light scatter], wide angle, side scatter, or orthogonal light scatter) measurement of light at right angles to the incident light source Project: H42, H43, H52 NOTE: This measurement is related to the internal and surface complexity of a cell or particle, such as cytoplasmic granularity, membrane irregularity, and/or nuclear shape.
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sigma value expression of process capability as “defects per million opportunities”; low sigma values (0 to 2) reflect too much process variation; moderate sigma values (2 to 4.5) reflect that most process output meets requirements; high sigma values (4.5 to 6) reflect that virtually all process output meets requirements Project: QMS12
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sigmoidoscopy visual examination of the rectum and sigmoid flexure of the colon by using a lighted tube; often performed for suspect amebiasis cases (Entamoeba histolytica) Project: M28
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signal a quantity that represents the measurand and which is functionally related to it (VIM93-2.8) Project: I/LA18, DI01, MM12, MM16, MM22, MM24 NOTE 1: Generally, a signal is the chemical, radioactive, luminescent, or colorimetric output of an assay detection system; NOTE 2: In microarray analyses, signal is the fluorescence intensity information captured by the detection system.
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signal strength in sequencing, the signal intensity represented by the peak height associated with the termination of a sequence product, leading to the detection of a base by the base caller Project: MM18 NOTE: Signal strength allows for the identification of a base above the noise but is often normalized and thus not to be used for quantification.
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signal word indicates the relative level of severity of hazard and alerts the reader to a potential hazard on the label. The signal words used are “danger” and “warning” (see A Guide to the Globally Harmonized System of Classification and Labelling of Chemicals [GHS]) Project: GP17 EXAMPLE: Danger is used for the more severe hazards, while warning is used for less severe hazards.
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signature a nucleic acid sequence region unique to an organism of interest that allows discrimination from other organisms (either those closely related or those expected to be present in the same sample type) Project: MM03, M55
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signature one or more nucleic acid sequences unique to an organism of interest that allows discrimination from other organisms (either those closely related or those expected to be present in the same sample type) Project: MM22
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significance testing the testing of a statistical hypothesis in such a manner that failure to reject it at a specified significance level does not imply acceptance of the hypothesis
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significant change a change that affects the quality or accuracy of the system Project: AUTO13
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silanization the preparation of glass or similar surfaces with silane Project: MM12 NOTE: Silane decreases the amount of surface oxides and facilitates the linkages of carbon based molecules to those surface.
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silent mutation a mutation that does not result in a change to an amino acid of a protein Project: M24 NOTE 1: A silent mutation does not confer drug resistance when the mutation occurs in a gene associated with drug resistance; NOTE 2: Often used interchangeably with “synonymous mutation.” However, a synonymous mutation may not always be silent. When it affects transcription, splicing, and messenger RNA transport and translation, it will not be silent.
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similar in bacterial strain typing, the results for two isolates are described as “similar” if they fail to meet the criteria for either indistinguishable or different Project: MM11, MM24 NOTE 1: Isolates with similar genotypes are presumed to be genetically related at some level; NOTE 2: The relative size of this “gray zone” between the two defined categories varies for different typing systems and, potentially, for the same typing system applied to different species (see Section 9 of CLSI document MM11); NOTE 3: See also different, indistinguishable.
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Simple Network Time Protocol a simplified version of Network Time Protocol that can be used by small, lightweight clients (RFC-2030) Project: POCT01
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single antigen refers to HLA antibody assay systems that have a single purified human leukocyte antigen antigen on a particular bead or well NOTE: A set of beads or wells, each with a different single antigen attached, is used to determine antibody specificity.
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single nucleotide polymorphism a sequence variant involving a change in a single nucleotide Project: MM01, M55, MM26 NOTE: The term is often used broadly to encompass any single-nucleotide change, including point mutations.
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single nucleotide polymorphisms DNA sequence variations that occur when a single nucleotide (adenine, thymine, cytosine, or guanine) in the genome sequence is changed Project: MM03
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single test ligand assays rely on observations of the reactions between “binding pairs,” one of which may be, eg, an antibody or binding protein Alternate Term: direct ligand assays Project: C45 NOTE: These measurement procedures may consist of three different formats: “two-step,” “one-step labeled hormone-analog,” and “one-step labeled antibody”
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single-base chain extension a solution-based enzymatic method for determining the identity of a nucleotide base at a specific position along a nucleic acid; an oligonucleotide primer annealed to a complementary sequence is enzymatically extended a single base by a nucleotide terminator complementary to the nucleotide being identified
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single-parameter display frequency distribution of measured signal intensities (ie, channel numbers) observed for cells within a population Alternate Term: histogram Project: H42, H43, H52
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single-platform method a method for the determination of absolute cell concentration with all data derived from flow cytometric measurements Project: H42, H43 NOTE: The determination of concentration requires an assessment of the volume of sample analyzed, and may be determined either directly by volumetric methods or indirectly by the addition of fluorescent beads at a known concentration. The latter method is more commonly used with the current generation of instrumentation. Single-platform methods are judged superior to dual-platform methods.
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singleplex an assay for a single target Project: MM17
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singleplex assay the quantitative or qualitative analysis of a single analyte Project: NBS06
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singlet state excited state of a molecule in which the electrons in the higher-energy and lower-energy orbitals have paired spins Project: I/LA24 NOTE 1: Transitions to and from singlet states, which do not require changes of spin, have a high probability of occurrence; NOTE 2: Fluorescence is the emission resulting from transition from a singlet state to a ground state.
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single-use device an in vitro diagnostic device that is intended to be used to test for a specific analyte or group of analytes in a specimen obtained from an individual patient and then to be disposed of. It is not intended to be reprocessed and used again Project: M53
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site the physical location where laboratory testing is performed Project: POCT04
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skin puncture 1) breakage of skin with a needle or lancet to produce blood for collection and testing; 2) collection of capillary blood by producing a break in the skin in an area of the body with a high density of capillaries, eg, fingertip or heel Project: AST02, C31, H49, POCT04
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skin puncture device sharp, needle-like device or incision device, commonly referred to as a lancet, used to puncture skin or obtain blood (eg, from finger or heel)
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slope the relationship between the change in y and the change in x between any two points along a line Project: H51, H58 NOTE 1: Slope is represented by the symbol “m” in the linear equation y = mx + b; NOTE 2: This may be either positive or negative.
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slurry a suspension of an insoluble substance with a liquid Project: H09
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small molecules commonly used to describe compounds analyzed by mass spectrometry that are less than 1500 Da Project: C50 NOTE: These are typically endogenous compounds involved in various biochemical processes and interact with biopolymers.
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small world network a regional interconnected network of community-based health service providers, such as primary care units, mobile medical units, and community hospitals, linked to larger regional hospitals and/or tertiary care centers Project: POCT16
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small-quantity generator a generator of 100 to 1000 kg of hazardous chemical waste in any given calendar month Project: GP05 NOTE 1: For an institution, this may be interpreted as the total hazardous chemical waste in aggregate per calendar month; NOTE 2: A small-quantity generator is required to obtain an Environmental Protection Agency identification number before he or she treats, stores, disposes of, transports, or offers hazardous waste for transportation; this is referred to as notification and is not considered an application, license, or permit.
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SNOMED Clinical Terms (SNOMED CT©) 1) the Systematized Nomenclature of Medicine Clinical Terms, a copyrighted work of the International Health Terminology Standards Development Organization; 2) is considered to be the most comprehensive, multilingual clinical health care terminology in the world; 3) includes 19 hierarchies such as clinical finding/disorder, procedure/intervention, body structure, organism, and substance; 4) SNOMED CT© is compatible for use with health care standards HL7 and DICOM and health care classifications; 5) previous versions (eg, SNOMED II, SNOMED International, and SNOMED Reference Terminology [SNOMED RT]) are encompassed in SNOMED CT©. Http://www.ihtsdo.org Alternate Term: SNOMED CT Project: AUTO01, AUTO02, AUTO03
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sodium heparin the commercially prepared sodium salt of heparin
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soft ionization an ionization process that produces minimal fragmentation Project: C50
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softening a water treatment process whereby cations, notably divalent cations such as Ca++ and Mg++, are exchanged for sodium using cation-exchange resins in the sodium form Project: GP40
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software the programming language to operate the hardware, devices, and computerized equipment Project: POCT02
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solid phase one of several support media to which either target or probe nucleic acids are immobilized Project: MM01, MM10, MM12, MM24 NOTE: Examples include nylon or nitrocellulose membrane, beads, magnetic particles, microtiter plate wells, glass particles or slides, and silicon chips.
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solid phase assays assays in which critical components are bound to a solid surface, such as plastic microtiter plates, polyresin beads, magnetic beads, charged membranes, or silica chips, upon which the reaction occurs Project: ILA29
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solid waste defined by EPA as any solid, liquid, or gaseous waste Project: GP05, QMS28 NOTE 1: means any waste that is not regulated or hazardous; NOTE 2: In QMS28, solid waste means any waste that is not regulated or hazardous
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solution answer that is suggested or implemented that solves a question or problem
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somatic gene variant a mutation that occurs in a nongermline tissue
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sorption either or both of the processes of absorption and adsorption Project: GP40
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sorting act of dividing a group of persons or things related by having something in common Project: QMS02
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source (material or sample) natural or synthetic specimens used to construct proficiency testing challenges Project: MM14
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source reagent a reagent that has the potential to contaminate other system reagents Project: EP47 NOTE: Residual material from the source reagent can be transferred by splashing or added directly into a second reagent or a reaction cell.
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source reduction method of avoiding the generation of waste through reduction in the amount or hazard of the waste generated Project: GP05, QMS28 NOTE: It is considered the preferred method of waste minimization; examples of source reduction include scaling down a process to generate less waste, changing a process to eliminate waste generation, and substituting materials to reduce or eliminate the hazard of the waste.
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source separation separation of wastes at the point of generation into management or disposal categories Project: GP05
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sourcing (material or sample) natural or synthetic specimens used to construct proficiency testing challenges; designed to analyze as many parameters of the test as possible
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sourcing process for finding, evaluating, and engaging suppliers of products and services Project: QMS21
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Southern blot a solid phase membrane to which DNA, transferred from a gel after electrophoresis, is bound so it can be hybridized with a labeled nucleic acid probe Project: MM01, MM22, MM24
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Southern blot a solid phase membrane to which DNA, which was transferred from a gel after electrophoresis, is bound so that it can be hybridized with a labeled nucleic acid probe Project: MM02, MM10, MM12
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Southern blot DNA that has been transferred from a gel following electrophoresis and bound to a solid support membrane so that it can be hybridized with a labeled nucleic acid probe Project: MM05
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Southern blot a solid phase membrane to which DNA, transferred in situ from a gel after electrophoresis, is bound so that it can be hybridized with a labeled nucleic acid probe Project: MM19
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span modulus of the difference between the two limits of a nominal range; EXAMPLE: for a nominal range of -10 V to +10 V, the span is 20 V NOTE: In some fields of knowledge, the difference between the greatest and smallest values is called range.
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spare part component intended to replace an identical or similar component of an instrument or other apparatus without affecting its functionality (ISO 18113-1) Project: ISO 18113-1
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sparging injection of gas below the water surface to remove other dissolved gases and volatile organic compounds Project: GP40
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spatial resolution average probe density across a defined genomic distance and by the mean intermarker distance Project: MM21
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special care baby unit a medical unit providing specialized care for preterm, low birth weight, or sick babies above the level provided for newborns rooming with the mother or in well-baby nurseries Project: NBS03 NOTE: See also neonatal intensive care unit.
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special cause variation variation from sources outside the testing process NOTE 1: Sources of special cause variation include interferences, operator error, instrument malfunction, and deterioration of reagents; NOTE 2: Special cause variation is also known as “assignable cause variation” or “process error.”
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specialist an individual with specific clinical laboratory education and experience, extensive experience in recommending and validating test methods, performing laboratory tests, and running and evaluating quality control Project: POCT08
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specialty care provider health care professional who provides specialized medical services (eg, endocrinology, metabolics, hematology, genetic counseling) Project: NBS02 NOTE: See health care provider and primary health care provider.
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species rank in taxonomic lineage Project: MM18 NOTE: Genus is one rank lower than species.
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specific activity a measurable event per unit mass per unit time Project: I/LA23
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specific heat the heat required to raise the temperature of one gram of a substance one degree centigrade Project: GP28
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specification a document that specifies, in a complete, precise, verifiable manner, the requirements, design, behavior, or other characteristics of a system or component, and often, the procedures for determining whether these provisions have been satisfied; contrast with requirement (IEEE 610.12-1990) Project: AUTO08
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specification any requirement with which a product, process, service, or other activity must conform (21 CFR 820) Project: QMS01, QMS21, EP19 Source: Quality Glossary
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specificity (analytical) in quantitative testing, the ability of a measurement procedure to determine only the component (measurand) it purports to measure or the extent to which the assay responds only to all subsets of a specified measurand and not to other substances present in the sample Project: H44, H26, H02, MM22, C57 NOTE: For qualitative or semiquantitative tests, the method’s ability to obtain negative results in concordance with negative results obtained by the reference method.
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specificity (clinical) test negativity in health; true-negative fraction; ability of a test to correctly identify the absence of disease at a particular decision threshold Project: H26 NOTE: In predictive value theory, clinical sensitivity is mathematically defined as the proportion of test results that are true negatives, divided by the sum of true negatives and false positives. See also predictive value.
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specificity the ability of a test or procedure to correctly identify or quantify an entity in the presence of interfering phenomena/influence quantities Project: EP14, H20, C43, C49 NOTE 1: In quantitative testing, the ability of a measurement procedure to determine only the component it purports to measure or the extent to which the assay responds only to all subsets of a specified analyte and not to other substances present in the sample; NOTE 2: For qualitative or semiquantitative tests, the method’s ability to obtain negative results in concordance with negative results obtained by the reference method; NOTE 3: For qualitative or semiquantitative tests, the measurement procedure’s ability to obtain negative results in concordance with negative results obtained by the reference measurement procedure.
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specificity ability of a measurement procedure to measure solely the measurand (modified from ISO 17511) Project: C58, MM12, MM16, H57, EP18, MM19, MM01, MM20, C62 NOTE 1: Specificity has no numerical value in this context; NOTE 2: Diagnostic sensitivity refers to the ability to detect disease using the test results, rather than to the analytical sensitivity of the determination; NOTE 3: See measurand.
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specificity (diagnostic or clinical) the ability of the test to correctly identify the absence of the disease at a particular decision threshold (ie, a negative result and identification of patients who do not have a disease) Project: H20 NOTE 1: The clinical disorder must be defined by criteria independent of the test under consideration; NOTE 2: In predictive value theory, clinical sensitivity is mathematically defined as the proportion of test results that are negative when the reference results are negative (true negatives/true negatives + false positives).
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specificity See analytical specificity and clinical specificity Project: M53
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specificity ability of a test or procedure to correctly identify or quantify an entity in the presence of interfering phenomena/influence quantities; the ability of a measurement procedure to measure solely the measurand Project: I/LA23, MM06, H02, QMS24 NOTE 1: In the context of quality control, the probability that a quality control system will indicate absence of special cause variation (ie, process error) when special cause variation is truly absent; NOTE 2: One minus the probability of “false alarms” wherein quality control data points exceed tolerance limits yet no error can be identified in the test system; NOTE 3: In immunology, specificity is an antiserum quality defining its reactivity with defined antigens and lack of specificity is the inaccuracy introduced by cross-reacting and/or interfering substances, because cross-reacting substances compete with the analyte for antibody-binding sites; NOTE 4: Specificity has no numerical value in this context.
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specificity (analytical) the ability of a test or procedure to correctly identify or quantify an entity in the presence of interfering phenomena/influence quantities Project: I/LA26, H48 NOTE: In quantitative testing, the ability of a measurement procedure to determine only the component it purports to measure or the extent to which the assay responds only to all subsets of a specified analyte and not to other substances present in the sample.
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specificity (of a measuring system) the ability of the test to correctly identify the absence of the disease at a particular decision threshold (ie, a negative result and identification of patients who do not have a disease) Project: H59 NOTE: From predictive value theory, the proportion of subjects who do not have a condition who have a negative test.
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specificity proportion of unaffected individuals with a negative test result Project: I/LA25 NOTE: It is the complement of the false-positive rate, ie, the false-positive rate, expressed as a percentage subtracted from 100%.
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specificity (diagnostic) the ability of a test to give a negative result for subjects who do not have the disease or condition for which they are being tested Project: EP24 NOTE 1: It is measured as the ratio of negative test results in those unaffected by the condition to the total number of condition-free subjects, and is often expressed as a percentage; NOTE 2: Formerly, the term “clinical specificity” was used in CLSI documents.
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specificity the ability of a measurement procedure to correctly measure a quantity in the presence of any influence quantity Project: C56 NOTE: In C56, the “influence quantity” would be any hemolysis, icterus, or lipemia/turbidity interference.
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specificity the ability of a test to detect only the disease or condition it is intended to find Project: POCT08, POCT15 NOTE 1: “Analytical specificity” is the test’s ability to detect only the material it is supposed to measure, while not being affected by other substances in the sample; NOTE 2: “Diagnostic specificity” (also referred to as “clinical specificity”) is the percentage of persons without the disease who have a negative test; NOTE 3: A highly specific test does not wrongly identify many people as being affected by the disease but may not (depending on its sensitivity) be effective at finding people who do have it.
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specificity (analytical) the ability of an analytical method to determine only the component it intends to measure; the extent to which the assay responds only to (all subsets of) a specified analyte and not to other substances present in the sample Project: I/LA34 NOTE: Within the context of this guideline, specificity refers to an assay that is specific for immunoglobulin E and shows no cross-reactivity of the antihuman immunoglobulin E reagent with other classes of human antibodies (eg, immunoglobulin G, immunoglobulin A, immunoglobulin M, and immunoglobulin D). Tests of reagent specificity should demonstrate that the antibody being measured is immunoglobulin E and that it is specific for the allergen of interest based on soluble allergen inhibition studies. The specific immunoglobulin E assay system should be tested for interfering substances, including but not limited to, lipids, hemoglobin, and medications and drug incipients commonly used by allergic patients, and any known interference should be identified.
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specificity (analytical) ability of a test or procedure to correctly identify or quantify an entity in the presence of interfering phenomena or influence quantities; the ability of a measurement procedure to measure solely the measurand Project: C52 NOTE: See cross-reactivity.
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specimen discrete portion of a body fluid or tissue or other sample associated with the human body taken for examination, study, or analysis of one or more quantities or characteristics to determine the character of the whole Alternate Term: primary sample Project: POCT05, MM09, PRE05, PRE01, PRE04, GP48, QMS24, MM20, ISO 15189, EP34, NBS04, EP07, C63, MM17, QMS22, C34, GP33, NBS09, NBS08, NBS05, POCT15, MM24, EP39, EP14, EP12 EXAMPLE 1: Biological entities can be, for example, laboratory animals, recombinant material generated from DNA, or human subjects; EXAMPLE 2: Examples include whole blood, urine, stool, cerebrospinal fluid, or solid tissues; NOTE 1: In some countries, the term “specimen” is used instead of primary sample (or a subsample of it), which is the sample prepared for sending to, or as received by, the laboratory and which is intended for examination (ISO 15189); NOTE 2: A specimen is a discrete portion of a body fluid or tissue taken for examination, study, or analysis of one or more quantities or characteristics to determine the character of the whole (ISO 18113-1); NOTE 3: For the purposes of EP34, a specimen may be composed of blood drawn into a collection tube; NOTE 4: The term “neat specimen” may be used to emphasize that the specimen is unmodified; for example, spiking or dilution have not been performed on the specimen; NOTE 5: For newborn screening, the dried blood spot specimen is collected; NOTE 6: For the purposes of EP07 and EP12, a specimen is the component taken directly from the body, with or without anticoagulants and preservatives, that has not been physically or chemically changed, except that it may have been centrifuged (ie, blood cells have been separated from the serum or plasma); NOTE 7: See sample; NOTE 8: The substance may still be referred to as a “specimen” if it was processed from the obtained specimen; thus, examples of specimens include whole blood and serum or plasma prepared from whole blood; saliva; cerebrospinal fluid; feces; urine; fingernail clippings; hair clippings; and tissue, even if embedded in a paraffin block; NOTE 9: For the purposes of CLSI C34, a specimen is the component taken directly from the body, with or without anticoagulants and preservatives, that has not been physically or chemically changed, except that it may have been centrifuged (ie, blood cells have been separated from the serum or plasma); NOTE 10: Biological material that is obtained to detect or measure one or more quantities, such as amount or concentration; NOTE 11: EP14 should not be used to measure the difference between specimen types.
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specimen discrete portion of a body fluid or tissue taken for examination, study, or analysis of one or more quantities or characteristics to determine the character of the whole (ISO 18113-1) Alternate Term: primary sample Project: AUTO01, H21, H44, H51, GP28, EP23, I/LA26, MM14, AUTO07, C52, MM19, MM03, I/LA02, H30, AUTO02, MM13, MM12, H26, MM06, MM01, H20, C49, MM22, GP16, H58, H42, H43, H47, H57, M55, ISO 18113-1, GP39, H59, GP34, AUTO12, H02, C58, MM20, H52, H60, C62, GP23, C57, MM23, POCT06, GP47, EP19, 18113-1, EP33, H48, POCT17, C24, I/LA20, AUTO14 EXAMPLES: Whole blood, urine, stool, cerebrospinal fluid, or solid tissues; NOTE 1: Global Harmonization Task Force uses the term specimen in its harmonized guidance documents to mean a sample of biological origin intended for examination by a medical laboratory; NOTE 2: Adapted from Global Harmonization Task Force, Essential Principles of Safety and Performance of Medical Devices (including In Vitro Diagnostic Devices), Final Document GHTF/SG1/N041:2005; NOTE 3: “Sample” can also be defined as an aliquot from a primary patient specimen (or from what ISO 18113 calls “primary sample”), or a derivative of a specimen, such as a cell line or diluted aliquot; NOTE 4: Statisticians use “sample” in a different although related sense, to refer to a selection of a representative set from a larger population for statistical testing; NOTE 5: The substance may still be referred to as a specimen if it was processed from the obtained specimen; thus, examples of specimens include whole blood and serum or plasma prepared from whole blood; saliva; cerebrospinal fluid; feces; urine; fingernail clippings; hair clippings; and tissue samples; NOTE 6: For plasma-based coagulation testing, the specimen would be anticoagulated whole blood or plasma; NOTE 7: For complete blood count testing, the usual specimen is EDTA-anticoagulated whole blood; NOTE 8: For example, a sample is taken from the patient specimen and used to obtain information by means of a specific laboratory test; NOTE 9: In some countries, the term “specimen” may be used to mean a sample of biological origin intended for examination by a medical laboratory; NOTE 10: The substance may still be referred to as a specimen if it was processed from the obtained specimen; thus, examples of specimens include blood and serum or plasma prepared from blood; bone marrow aspirate; body fluid; saliva; cerebrospinal fluid; feces; urine; fingernail clippings; hair clippings; tissue samples, even if embedded in a paraffin block; etc.; NOTE 11: A specimen is a portion of tissue, body fluid, or urine obtained from a patient for diagnostic purposes; NOTE 12: In CLSI MM23, the “whole” refers to the patient’s clinical condition; NOTE 13: A single biological specimen may be aliquotted into multiple samples for analysis as needed.
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specimen biological material that is obtained in order to detect or to measure one or more quantities, such as amount or concentration (ISO/CD 18112-1) Alternate Term: primary sample Project: ISO CD 18112-1, GP43, H56 NOTE: Examples include whole blood, urine, stool, cerebrospinal fluid, or solid tissues.
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specimen the discrete portion of a body fluid (typically in the case of I/LA34: serum/plasma) or extract of a tissue taken for analysis of one or more quantities or characteristics to determine the character of the whole Project: I/LA34
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specimen (patient) the discrete portion of a body fluid taken for analysis of one or more quantities or characteristics to determine the character of the whole Project: C56
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specimen (patient) discrete portion of a body fluid, breath, hair, or tissue taken for examination, study, or analysis of one or more quantities or properties assumed to apply for the whole Project: M53, PRE02, EP35, NBS10, POCT16 NOTE: For newborn screening, the dried blood spot specimen is collected.
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specimen acceptability (for newborn screening) determination of a specimen’s fitness for use, based on criteria for acceptability and unacceptability:
acceptable dried blood spot specimen – a dried blood spot specimen with a quantity and quality of blood, along with complete demographic and clinical data, that meet program criteria; NOTE 1: A specimen can be determined to be acceptable for all newborn screening tests or for only a portion of tests, with a repeat specimen needed to complete all screening tests; NOTE 2: See dried blood spot and re-collection.
unacceptable dried blood spot specimen – a dried blood spot specimen with a suboptimal quantity and/or quality of blood or with missing demographic or clinical data, according to program criteria; NOTE 1: A specimen can be determined to be unacceptable for all newborn screening tests or for only a portion of tests. In both scenarios, a repeat specimen is needed to complete all screening tests; NOTE 2: If a program chooses to test unacceptable dried blood spot specimens, the results might be unreliable or inaccurate, and the screening results report should include a disclaimer, with a request for a repeat specimen; NOTE 3: An unacceptable specimen is also commonly referred to as an “unsatisfactory specimen”; NOTE 4: See dried blood spot and re-collection. Project: NBS01, NBS13, NBS02 Source: Newborn Screening Glossary
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specimen carrier a device that holds the specimen container Alternate Term: sample carrier; carrier; puck Project: AUTO01, AUTO07, AUTO02, AUTO12 NOTE: The specimen carrier interfaces mechanically with the transportation system to move the specimen from location to location and may carry one specimen container or many specimen containers.
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specimen collection container the tube that holds a patient specimen Alternate Term: sample container; container; specimen container; tube; test tube Project: AUTO01, AUTO07, AUTO02 NOTE: The container typically consists of a glass or plastic closed-end tube with a removable closure on the opposite end.
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specimen collection container the container that holds a patient specimen; the container may be a tube, cup, or other container Project: AUTO12
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specimen container See specimen collection container Project: AUTO02
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specimen container detail the data necessary to maintain the containers that are being used throughout the laboratory automation system Project: AUTO16
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specimen matrix milieu in which the analyte exists Project: C56 NOTE 1: Clinical specimen matrices include serum, plasma, urine, cerebrospinal fluid, and other body fluids; NOTE 2: In C56, the specimen matrices are serum and plasma.
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specimen probe a part of an instrument or specimen processing and handling device that aspirates fluid from a specimen and delivers it to the instrument for analysis Project: AUTO01, AUTO02 NOTE: The sample probe can also be called sample proboscis, nozzle, needle, or sampling mechanism.
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specimen transport temperature the temperature at which the device is stored or transported to the laboratory once the device has been used to collect a clinical specimen. This temperature is defined by the end user to ensure maximum microorganism viability Project: M40 NOTE: It is especially important that “specimen boxes” located outside of a physician’s facility not be subjected to extremes of temperature outside of the range established by the laboratory. Moreover, specimens should not be subjected to repeated temperature fluctuations.
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specimen-positioning system a device to position a specimen container within acceptable tolerances of a point of reference Alternate Term: sample-positioning system; SPS Project: AUTO01, AUTO02
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specimen-specific bias difference between the measured value and the true value that results from a characteristic or property of the specimen, as opposed to a characteristic of the measurement procedure (eg, calibration, reagent instability) Project: C56 NOTE: It is the interference effect exhibited by an individual specimen.
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spectral database a collection of mass spectra that are characteristic of various microorganisms and can be used to identify unknown microorganisms by comparing them with spectra derived from the unknown microorganisms Project: M58
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spectral overlap the phenomenon in which a fluorochrome exhibits fluorescence that “spills over” into a detector channel where it is not expected to appear Project: H62
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spectral slitwidth the total wavelength range, in nanometer, emerging from the monochromator exit slit Project: H15
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spectrophotofluorometer a fluorometer that uses monochromators to allow a continuum of wavelengths to be scanned for illumination or detection Project: I/LA24
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spectrophotometer an instrument with an entrance slit and one or more exit slits, with associated equipment, designed to furnish the ratio, or a function thereof, of the radiant power of two beams as a function of spectral position. The two beams may be separated in time, space, or both. The instrument is capable of isolating spectral bands narrower than 10 nm Project: H15
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spectrum (pl. spectra) an array of entities, such as light waves or particles, produced by the dispersion of radiant energy, and ordered in accordance with the magnitude of a common physical property, such as wavelength, frequency, or mass NOTE: Commonly, the band of colors visible to the naked eye that is produced when sunlight or other broad-band light is passed through a prism or refracted by a grating.
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spectrum (of the condition) various presentations of the condition of interest due to expected dissimilar manifestations with respect to various matrix characteristics Project: EP24 NOTE 1: In a testing situation, the condition of interest is usually defined to be binary, ie, it is either present or absent; NOTE 2: Notwithstanding this generalization, the condition of interest can often be expected to manifest itself differently with respect to various conditions (eg, stage of disease, severity of disease, genetic background, body composition, comorbidity, lifestyle, and demographics) that cannot be captured when dichotomizing its continuum.
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spectrum bias given a test and its intended application, the bias between estimated test performance and true test performance when the sample used for evaluating an assay does not properly represent the entire disease spectrum over the target (intended-use) population Project: EP24 NOTE 1: Spectrum bias is due to spectrum effect when one is not careful with the study design, ie, when the subject selection method departs substantially from true random sampling. When this occurs, biased estimates of sensitivity, specificity, receiver operating characteristic curves, and their summaries will result; NOTE 2: Spectrum bias can be summarized, in mathematical terms, as a problem created by improper sampling.
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spectrum effect effect that sampling different condition substrata in a population will have on test performance estimators Project: EP24
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specular area refers to the portion on a field of view where the light from the illumination on the reader is reflected directly back into the detection subsystem resulting in saturation and ensuing loss of dynamic range Project: AUTO14 NOTE: This dynamic range is what allows the detection subsystem to establish a gray-scale value for an area being evaluated by specific pixels
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specular reflection the reflection of light rays from a surface at the same angle as the light rays hit the surface Project: AUTO14 NOTE 1: Light will be reflected from an object in two different ways: Sspecular (mirror-like) and diffuse; NOTE 2: The proportions between the two types are dependent on the surface properties of the object being illuminated; NOTE 3: An optical-grade mirror will produce a reflection that is almost exclusively specular, resulting in almost no diffuse reflection. Inversely, a matte white surface will produce a reflection that is almost exclusively diffuse, resulting in almost no specular reflection; NOTE 4: Specular reflection is unidirectional in nature; NOTE 5: On typical label-stock, specular reflection will often be present to an extent that requires awareness and management. While flat surfaces allow for relatively easy specular reflection management, curved surfaces such as specimen tubes or vials typically require more consideration as a significant range of angles between object, illumination, and detection system are present
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spherule a round structure containing endospores; characteristic of Coccidioides species in host tissue Project: M54
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spiked sample a sample to which known concentrations of specific analytes have been added in such a manner as to minimize the change in the matrix of the original sample Project: MM17 NOTE: Every spiked sample analyzed should have an associated reference to the spike solution and the volume added.
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spiking addition of a known quantity of a substance (or analyte) to a sample in order to allow determination of sensitivity of detection through titration Project: H52
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spiking preparation of a sample(s) by the comingling of pure standard analyte material with a specimen Project: EP34 NOTE: Spiking can also be accomplished using a patient specimen with a high measurand concentration value instead of pure standard analyte material.
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spill kit set of equipment used for the removal of chemical or microbiological material from a laboratory surface or apparatus Project: ISO15190 (March 2002)
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spillover matrix for a cytometer in which there are N detectors for N fluorochromes, the spillover matrix is the N × N matrix of the percent spillover of every fluorochrome into every detector Project: H62 NOTE: See percent spillover and fluorescence spillover.
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Spinnbarkeit a measure of tenacity (from German), ie, the ability to form a thread, viscosity Project: POCT10, HS02
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spiral cone beam computed tomography a type of three dimensional computed tomography in which an X-ray source describes a helical trajectory relative to the object while a two dimensional array of detectors measures the transmitted radiation on part of a cone of rays emanating from the source Alternate Term: helical cone beam computed tomography Project: H59 NOTE: More recently, the term computed tomography pulmonary angiography has also been used synonymously.
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splashguard device used to prevent personal contamination by a liquid Project: ISO15190 (March 2002)
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split identification identification resulting from the inability to distinguish two or more (closely related) species Project: M58 NOTE: Such reporting should be reserved for organisms with similar virulence and susceptibility profiles.
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split-sample comparison a testing condition in which a single sample is divided into aliquots with one aliquot tested on a particular instrument or by a particular laboratory and the other aliquot(s) tested on another instrument(s) or in other laboratories, followed by the comparison of results Project: QMS24
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split-sample testing a testing condition in which a single sample is divided into aliquots with one aliquot tested on a particular instrument or laboratory and the other aliquot(s) tested on other instrument(s), or laboratory, followed by the comparison of results
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split-sample testing repeat testing of aliquots of a single sample under conditions that differ from the original analysis to assess the validity of the original result; EXAMPLE: Testing on a different instrument, at a different time, or by a different analyst
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split-specimen testing a test involving two biologic specimens obtained at the same time from the same source on two or more different assay systems (or by two or more analysts), often in two or more different laboratories NOTE: For example, testing two tubes of blood collected from a particular patient during the same venipuncture.
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SpO2 in pulse oximetry, an estimate of the arterial oxygen saturation derived by measuring relative absorption of red and infrared light by pulsating arterial blood Project: POCT11
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spore one of the stages in the life cycle of the microsporidia; contains a polar tubule apparatus used for infecting cells; the number of polar tubule coils in the spore is used in organism classification (electron microscopy) Project: M28 NOTE: The size is usually 1 to 2 μm.
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spore a propagule that develops by sexual reproduction (ascospore, basidiospore, or zygospore) or by an asexual process involving cytoplasmic cleavage within a sporangium (sporangiospore)
Project: M54
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spot when testing with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, a discrete deposit of biomass and matrix for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis Project: M58
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spot the physical location of a single hybridization event on the microarray solid surface with the final fluorescent signal Project: MM22, MM24
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spotting the transfer of microorganism biomass from a culture medium onto a target slide or plate Project: M58
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spread the distribution of a given population for a given parameter that is measured as robust standard deviation. The spread of a population may be due to natural biological variation and/or to other sources of measurement imprecision such as fluorescence spillover in a multicolor analysis Project: H62
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spreadsheet a table of values arranged in rows and columns Project: M39
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SPS See specimen-positioning system Project: AUTO02
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spurious result See discrepant result Alternate Term: discrepant result Project: C56
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squamocolumnar junction the current junction between the squamous and columnar epithelium Project: GP15
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squamous intraepithelial lesion precancerous cellular changes in the cervical epithelium, which encompasses a spectrum of cellular abnormalities including: low-grade squamous intraepithelial lesion, which encompasses mild dysplasia, mild dyskaryosis, cervical intraepithelial neoplasia I, koilocytosis, and human papillomavirus effect; atypical squamous cells—cannot exclude high-grade squamous intraepithelial lesion; high-grade squamous intraepithelial lesion, which encompasses moderate dysplasia, moderate dyskaryosis, cervical intraepithelial neoplasia 2, severe dysplasia/carcinoma in situ, severe dyskaryosis, and cervical intraepithelial neoplasia 3 Project: GP15 NOTE: The cervical intraepithelial neoplasia classification is normally used for histologic reporting; low- and high-grade squamous intraepithelial lesions are terms from the Bethesda System nomenclature for cervicovaginal cytology. In some laboratories, cervical intraepithelial neoplasia nomenclature has been replaced with Bethesda System terminology.
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stability (of a measuring instrument) property of a measuring instrument, whereby its metrological properties remain constant in time (JCGM 200:2012) Project: ISO IEC Guide 99, H26, C24 NOTE: Stability may be quantified in several ways: EXAMPLE 1: In terms of the duration of a time interval over which a metrological property changes by a stated amount; EXAMPLE 2: In terms of the change of a property over a stated time interval (JCGM 200:2012).
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stability the capacity for a product to retain its composition, characteristics, and properties during specified conditions Project: HS02, H49, POCT04 NOTE: ISO Guide 30/92-2.7 defines this as the “ability of a reference material, when stored under specified conditions, to maintain a stated property value within specified limits for a specified period of time” (Cf. POL1/2).
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stability ability of a measuring instrument to maintain constant its metrological characteristics with time Project: VIM93 NOTE 1: Where stability with respect to a quantity other than time is considered, this should be stated explicitly; NOTE 2: Stability may be quantified in several ways, for example:
-in terms of the time over which a metrological characteristic changes by a stated amount, or
-in terms of the change in a characteristic over a stated time.
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stability ability of an in vitro diagnostic medical device to maintain its performance characteristics within the limits specified by the manufacturer (ISO 18113-1)
Project: ISO 18113-1, ISO 18113-2, ISO 18113-3 NOTE 1: Stability applies to in vitro diagnostic reagents, calibrators, and controls, when stored, transported, and used in the conditions specified by the manufacturer; reconstituted lyophilised materials, working solutions, and materials removed from sealed containers, when prepared, used, and stored according to the manufacturer’s instructions for use; measuring instruments or measuring systems after calibration (ISO 18113-1); NOTE 2: Stability of an in vitro diagnostic reagent or measuring system is normally quantified with respect to time in terms of the duration of a time interval over which a metrological property changes by a stated amount or in terms of the change of a property over a stated time interval (ISO 18113-1); NOTE 3: Adapted from “stability of a measuring instrument” in JCGM 200:2012[28], 4.19 (ISO 18113-1).
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stability the ability of a product to maintain its performance characteristics consistently over time Project: EP25, EP18, EP23 NOTE: Stability applies to in vitro diagnostic products (eg, reagents, calibrators, controls) when stored, transported, and used in the conditions specified by the manufacturer; reconstituted lyophilized materials, working solutions, and materials removed from sealed containers when prepared, used, and stored according to the manufacturer’s instructions for use; and measuring instrument or measuring systems after calibration.
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stability ability of a measurand to retain its in vivo composition, characteristics, and properties Project: PRE04 NOTE: Instability relates to the propensity of the measurand to degrade or deteriorate due to time after removal from the patient or exposure to unfavorable conditions.
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stability monitoring real-time stability testing to ensure that an in vitro diagnostic product performs within specified claims Project: EP25 NOTE: This testing may be done for either shelf-life and/or in-use claims
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stability reference product reagent, calibrator, or control stored in presumed stable storage conditions and used as a baseline for an isochronous study or tested alongside an on-test reagent at each time point for a reference anchored real time stability study Project: EP25 NOTE 1: Measurement procedure drift is quantified by analyzing the relative recovery of the on-test product vs the reference product; NOTE 2: The stability reference product may be the same material as the on-test product but stored in the presumed stable storage conditions for the entire duration of the study. Alternatively, the stability reference product may be a separate reagent, calibrator, or control stored in a presumed stable storage condition (eg, lyophilized or frozen higher-order reference calibrators or control material); NOTE 3: May not be, and should be distinguished from, certified reference materials.
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stability study study/analysis/evaluation, performed during product development, to establish the expiration date of a product and to ensure the product will perform, as expected, when used or stored as recommended by the manufacturer Project: M50
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stability testing plan a written protocol, based on statistically valid sample size and testing interval considerations, designed to test the key stability attributes of a product with predefined acceptance criteria that support its labeled claims Project: EP25 NOTE: The experimental design and acceptance criteria leading to stability claims for a product are documented in the stability testing plan.
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stabilized blood product a material prepared from blood cells treated to prolong its usefulness as a quality control material Project: H44 NOTE: It can lack some of the functional characteristics of blood.
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stable isotope an atom of a given element with a higher mass (ie, in which the number of neutrons is greater) that is not radioactive Project: NBS04, NBS09 NOTE: Unstable radioisotopes emit radiation as they decay and are rarely used in tandem mass spectrometry.
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stable process process in a state of statistical control NOTE 1: A stable process will generally behave as though the samples from the process at any time are simple random samples from the same population; NOTE 2: This state does not imply that the random variation is large or small, within or outside of specification, but rather that the variation is predictable using statistical techniques; NOTE 3: The process capability of a stable process is usually improved by fundamental changes that reduce or remove some of the random causes present and/or adjusting the mean towards the preferred value; NOTE 4: In some processes, the mean of a characteristic can have a drift or the standard deviation can increase due, for example, to wear-out of tools or depletion of concentration in a solution. A progressive change in the mean or standard deviation of such a process is considered due to systematic and not random causes. The results, then, are not simple random samples from the same population.
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staff represent the collective group of employees employed in a particular organization or place of work Project: QMS16
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stage in EP19, the two stages of the Test Life Phases Model: Establishment and Implementation Project: EP19 NOTE: Each stage consists of several discrete phases as the test method is developed by the developer and used by the end-user laboratory.
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stagnation state of a liquid without current or circulation Project: GP40
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stain solution of one or more dyes at defined concentrations in a defined solvent used for staining Project: ISO19001 (February 2002) NOTE: The stain can be prepared by directly dissolving the dye in the solvent or by dilution of a stock solution with suitable agents.
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staining impartment of colour to a material by means of reaction with a stain or chromogenic reagent (ISO 19001) Project: ISO 19001, I/LA28
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stakeholder people, departments, and organizations that have an investment or interest in the success of actions being taken Project: QMS14 NOTE: Stakeholders may be external to a process, such as customers or suppliers, or they may be internal, such as project sponsors, managers, teams, or internal customers.
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stakeholder in GP36, persons or entities having a role in the emergency operations plan Project: GP36 NOTE: In the broadest sense, all inhabitants of a community are stakeholders of the local emergency operations plan; they will suffer if it fails. For the community, hospital, or laboratory, those of interest for the emergency operations plan development and operation are stakeholders who are in need of some special knowledge about how it will work and how their operations will change when it is activated; EXAMPLE: Employees, clients, referral laboratories, and other facility sections and departments could be stakeholders; they should have knowledge of the plan and an opportunity to suggest improvements to it.
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stakeholders people, departments, and organizations that have an investment or interest in the success of actions being taken NOTE: Stakeholders may be external to a process, such as customers or suppliers, or they may be internal, such as project sponsors, managers, teams, or internal customers.
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standard (measurement) realization of the definition of a given quantity, with stated quantity value and associated measurement uncertainty, used as a reference (JCGM 200:2012) Alternate Term: measurement standard Project: ISO IEC Guide 99, I/LA33, H26, MM19, C40 EXAMPLE 1: 1-kg mass measurement standard with an associated standard measurement uncertainty of 3 μg (JCGM 200:2012); EXAMPLE 2: 100 Ω measurement standard resistor with an associated standard measurement uncertainty of 1 μΩ (JCGM 200:2012); EXAMPLE 3: Caesium frequency standard with a relative standard measurement uncertainty of 2 × 10-15 (JCGM 200:2012); EXAMPLE 4: Hydrogen reference electrode with an assigned quantity value of 7.072 and an associated standard measurement uncertainty of 0.006 (JCGM 200:2012); EXAMPLE 5: Set of reference solutions of cortisol in human serum having a certified quantity value with measurement uncertainty for each solution (JCGM 200:2012); EXAMPLE 6: Reference material providing quantity values with measurement uncertainties for the mass concentration of each of 10 different proteins (JCGM 200:2012); NOTE 1: A “realization of the definition of a given quantity” can be provided by a measuring system, a material measure, or a reference material (JCGM 200:2012); NOTE 2: A measurement standard is frequently used as a reference in establishing measured quantity values and associated measurement uncertainties for other quantities of the same kind, thereby establishing metrological traceability through calibration of other measurement standards, measuring instruments, or measuring systems (JCGM 200:2012); NOTE 3: The term “realization” is used here in the most general meaning. It denotes three procedures of “realization.” The first one consists in the physical realization of the measurement unit from its definition and is realization sensu stricto. The second, termed “reproduction,” consists not in realizing the measurement unit from its definition but in setting up a highly reproducible measurement standard based on a physical phenomenon, as it happens, eg, in case of use of frequency-stabilized lasers to establish a measurement standard for the metre, of the Josephson effect for the volt or of the quantum Hall effect for the ohm. The third procedure consists in adopting a material measure as a measurement standard. It occurs in the case of the measurement standard of 1 kg (JCGM 200:2012); NOTE 4: A standard measurement uncertainty associated with a measurement standard is always a component of the combined standard measurementuncertainty (see ISO/IEC Guide 98-3:2008, 2.3.4) in a measurement result obtained using the measurement standard. Frequently, this component is small comparedwith other components of the combined standard measurement uncertainty (JCGM 200:2012); NOTE 5: Quantity value and measurement uncertainty must be determined at the time when the measurement standard is used (JCGM 200:2012); NOTE 6: Several quantities of the same kind or of different kinds may be realized in one device, which is commonly also called a measurement standard (JCGM 200:2012); NOTE 7: The word “embodiment” is sometimes used in the English language instead of “realization” (JCGM 200:2012); NOTE 8: In science and technology, the English word “standard” is used with at least two different meanings: as a specification, technical recommendation, or similar normative document (in French “norme”) and as a measurement standard (in French “étalon”). This Vocabulary is concerned solely with the second meaning (JCGM 200:2012); NOTE 9: The term “measurement standard” is sometimes used to denote other metrological tools, eg, ‘software measurement standard’ (see ISO 5436-2) (JCGM 200:2012).
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standard an authoritative “document” setting forth criteria for performance and characteristics (RHUD1.7CD) Project: VET04, VET03 NOTE 1: This definition is compatible with the use of “standard” in the US Code of Federal Regulations as well as in the context of CLSI use; NOTE 2: As a consequence of the conflicting use of the term as defined in definition 1, vs the following definitions, any use of the term “standard” shall be appropriately specified in context; 1) primary standard – a standard that is designated or widely acknowledged as having the highest metrological qualities and whose value is accepted without reference to other standards of the same quantity (VIM93); 2) secondary standard – a standard whose value is assigned by comparison with a primary standard of the same quantity (VIM93); 3) reference standard – a standard, generally having the highest metrological quality available at a given location or in a given organization from which measurements made there are derived (VIM93); 4) working standard – a standard that is used routinely to calibrate or check material measures, measuring instruments, or reference materials (VIM93); NOTE 1: A working standard is usually compared against a reference standard; NOTE 2: A working standard that is used routinely to ensure that measurements are being carried out correctly is called a “check standard” (VIM93); 5) primary measurement standard – measurement standard established using a primary reference measurement procedure, or created as an artifact, chosen by convention (JCGM 200:2012); 6) secondary measurement standard – measurement standard established through calibration with respect to a primary measurement standard for a quantity of the same kind (JCGM 200:2012); 7) reference measurement standard – measurement standard designated for the calibration of other measurement standards for quantities of a given kind in a given organization or at a given location (JCGM 200:2012); 8) working measurement standard – measurement standard that is used routinely to calibrate or check measuring instruments or measuring systems (JCGM 200:2012); NOTE 1: A working measurement standard is usually calibrated with respect to a reference measurement standard (JCGM 200:2012); NOTE 2: In relation to verification, the terms “check standard” or “control” standard are also sometime used (JCGM 200:2012).
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standard (measurement) material measure, measuring instrument, reference material or measuring system intended to define, realize, conserve, or reproduce a unit or one or more values of a quantity to serve as a reference Alternate Term: etalon Project: MM24 NOTES: A set of similar material measures or measuring instruments that, through their combined use, constitutes a standard is called a collective standard. A set of standards of chosen values that, individually or in combination, provides a series of values of quantities of the same kind is called a group standard. EXAMPLES: a) 1 kg mass standard; b) 100-ohm standard resistor; c) standard ammeter; d) caesium frequency standard; e) standard hydrogen electrode; f) reference solution of cortisol in human serum having a certified concentration.
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standard a published document that contains a set of rules to be used consistently as good principles, practices, or guidelines Project: QMS17 NOTE 1: A standard controls how people develop and manage materials, products, services, technologies, processes, and systems; NOTE 2: A rule can be referred to as a “standard.”
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standard deviation a statistical measurement of the distance from the mean of a series of measurements Project: H62 NOTE 1: It is a measure of precision, reproducibility, or dispersion of a frequency distribution; NOTE 2: See robust standard deviation.
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standard deviation (of a random variable, or of a probability distribution) the positive square root of the variance σ = √ V(X) (ISO 3534-1) Project: H54, H47, H57
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standard deviation a measure of variability/dispersion that is the positive square root of the population variance Project: MM06
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standard deviation 1) a measure of variability/dispersion that is the positive square root of the population variance (ASQC3); 2) Experimental standard deviation{//Sample standard deviation} The quantity characterizing the dispersion of the results for a series of measurements of the same measurand (modified from VIM93- 3.8) Project: EP10, EP31 NOTE 1: Given by the formula: SD = Ö[ (xj - )2/[n - 1] with x-bar being the arithmetic average {and/or mean} of the results being considered, [xi, 's]; NOTE 2: Considering the series of “n” values as a sample of a distribution, x-bar is an unbiased estimate of the mean, m, and (SD)2 is an unbiased estimate of the variance, s2, of that distribution {while SD is a biased estimator of the standard deviation; s}; (VIM93-3.8); NOTE 3: A number of formulae exist for calculating standard deviation; users of the CLSI EP10 protocol should use the formula shown in Appendix C of CLSI EP10.
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standard deviation a measure of the dispersion of a group of values around a mean Project: H26
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standard deviation the positive square root of the variance (V(X)): σ = √V(X) (ISO 3534-1 § 1.23) Project: C51 NOTE: The SD of the quantity x is symbolized sx or s(x).
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standard deviation for proficiency assessment measure of dispersion used in the evaluation of results of proficiency testing (ISO 13528) Project: QMS24
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standard error (of the mean) a measure of the dispersion of the mean of a set of measurements Project: H26
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standard measurement uncertainty See standard uncertainty Alternate Term: standard uncertainty; standard uncertainty of measurement Project: C51
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standard operating procedure a set of standardized and documented procedures that form the basis of any specified action Project: I/LA28 NOTE: A standard operating procedure is a procedure manual under the director’s responsibility.
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standard precautions set of precautions applied to all patients designed to reduce risk of transmission of microorganisms in the health care setting Project: GP17 NOTE: All blood, tissue, body fluids, secretions, and excretions (except sweat) are considered potentially infectious.
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standard precautions set of precautions applied to all patients, and all laboratory specimens from those patients, designed to reduce the risk of transmission of infectious agents in the health care setting Project: M29 NOTE: All blood, tissue, body fluids, secretions, and excretions (except sweat) are considered potentially infectious.
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standard reference data reference data issued by a recognized authority (JCGM 200:2012) Project: ISO IEC Guide 99 EXAMPLE 1: Values of the fundamental physical constants, as regularly evaluated and published by ICSU CODATA (JCGM 200:2012); EXAMPLE 2: Relative atomic mass values, also called atomic weight values, of the elements, as evaluated every two years by IUPAC-CIAAW at the IUPAC General Assembly and published in Pure Appl Chem or in J Phys Chem Ref Data (JCGM 200:2012).
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standard reference material certified reference materials Project: I/LA24, MM17 NOTE 1: These are well-characterized materials produced in quantity to improve measurement science; NOTE 2: Standard reference materials are certified for specific chemical or physical properties and are issued with certificates that report the results of the characterization and indicate the intended use of the material.
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standard reference material certified reference materials for specific chemical or physical properties that are issued with certificates that report the results of the characterization and indicate the intended use of the material Project: H62 NOTE: See reference material.
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standard reference reagent a preparation of thromboplastin reagent made by a similar procedure to that used for each individual lot of thromboplastin reagents Alternate Term: manufacturer's standard Project: H54, H47 NOTE 1: Generally, it is one batch or part of a batch of the normal manufacturer’s reagent that is retained as an internal standard. An international sensitivity index value is assigned according to the World Health Organization guidelines for standard reference reagents by at least two laboratories. The international sensitivity index value may be assigned by either the tilt-tube method or be an instrument-dependent value. This material is then used for subsequent international sensitivity index assignment of each lot of similar reagents; NOTE 2: The term does not imply that the standard is developed directly from the primary standard (VIM93), and it should be noted that a manufacturer’s standard may in fact be three or more calibration steps away from the primary standard.
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standard uncertainty (measurement) measurement uncertainty expressed as a standard deviation (JCGM 200:2012) Alternate Term: standard uncertainty of measurement; standard measurement uncertainty Project: EP32, ISO IEC Guide 99, C51, EP30 NOTE 1: The standard measurement uncertainty of the quantity x is symbolized ux or u(x); NOTE 2: The square of the standard measurement uncertainty of the quantity x is symbolized u2x or u2(x); NOTE 3: The standard measurement uncertainty of the quantity y is symbolized uy or u(y).
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standard uncertainty of measurement See standard uncertainty Alternate Term: standard uncertainty; standard measurement uncertainty Project: C51
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standardized method a procedure, the reliability of which has been validated by a collaborative study and which is recommended by a defined authority based on its accuracy, precision, economy of labor and materials, and ease of operation, for use in a laboratory analysis (ICSH, Rules and Operating Procedures. ICSH Secretariat, Leuven, Belgium, 1991) Alternate Term: standardized procedure Project: H07
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standardized method an alternative to a reference method when an appropriate international reference material is not available; this has all the other characteristics of a reference method Project: H02 NOTE: The erythrocyte sedimentation rate standardized method described in CLSI document H02, Section 7 is “a clearly and exactly described” technique.
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standing order a predictable repeating purchase order based on established usage patterns, particularly for reagents and products that have short expiry dates Project: QMS21
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staphylococcal cassette chromosome mec (SCCmec) a genetic island that typically contains the mecA gene, cassette chromosome recombinase (ccr) genes, and additional DNA sequences that may include other antimicrobial resistance genes. There are currently eight SCCmec elements (designated I through VIII) that have been described. These elements are present in most methicillin (oxacillin)-resistant species of staphylococci. Project: M55
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staphylococcal enterotoxin B a “superantigen” that is used as a polyclonal stimulator of T-cells expressing specific T-cell receptor Vβ families Project: I/LA26
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stateful inspection a method used by newer firewalls that doesn’t examine the contents of each packet, but instead compares certain key parts of the packet to a database of trusted information Project: AUTO09 NOTE: The outgoing information (transferred from inside the firewall to the outside) is monitored for specific characteristics, and then the incoming information is compared to these characteristics. If the comparison produces a reasonable match, the information is allowed to pass, otherwise it is discarded.
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static cytometry a recently introduced clinical technology which differs from flow cytometry in that fluorescently stained cells are optically measured in a fixed volume capillary Project: H44 NOTE: a) In this technique the laser continuously scans down the length of a disposable capillary, and the image of the cells is plotted and counted providing an absolute cell number in a defined volume; b) Gating strategies are similar to flow cytometry and include cell staining intensity, cell size, and color slope with multicolor capability.
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static effect dose or exposure resulting in the measure of the effect being unchanged from baseline to the time of evaluation (eg, the number of colony-forming units at t = 0 hour [baseline, start of treatment] and t = 24 hours [time of sampling]) Alternate Term: stasis Project: M23 NOTE: Specific use of the term “static” does not imply that no changes have occurred during the period of reference; indeed, kill and regrowth may have occurred (repeatedly) during this period, culminating in a net static effect. The time period over which the net static effect is measured and treatment started should be in relation to the setting of the baseline and stated explicitly.
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statistic a function of a set of observations from a random variable Project: EP31 NOTE: A statistic is also a random variable; thus, it also has statistics, such as mean and standard deviation.
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statistical power the power of a study refers to the probability of rejecting the null hypothesis when the alternative hypothesis is true. The power of a study increases with an increasing number of samples Project: EP19
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statistical process control activities focused on the use of statistical techniques to reduce variation, increase knowledge about the process, and steer the process in the desired way Project: C24
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statistical quality control a procedure in which stable samples are measured and the observed results compared with limits that describe the variation expected when the measurement method is working properly Project: AST03 NOTE: The expected variation is determined by analyzing stable control material many times, calculating the mean and standard deviation (SD) of those measurements, then calculating control limits as the mean plus and minus certain multiples of the SD. A control chart is prepared to display the observed result on the y axis versus time on the x axis. The control limits are drawn on the chart. New control results are plotted and compared with the control limits to assess whether the method is “control” (pints within control limits) or “out of control” (points outside of control limits).
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statistical significance statement denoting the outcome is outside the limits of probable outcomes under the null hypothesis Project: EP07 NOTE: An outcome is statistically significant when the P value associated with such an outcome is less than alpha.
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statistical significance statistical methods allow an estimate to be made of the probability of the observed or greater degree of association between independent and dependent variables under the null hypothesis; from this estimate, in a sample of given size, the statistical significance of a result can be stated Project: GP45 NOTE: Usually the level of statistical significance is stated by the P value.
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statistical tools methods and techniques used to generate, analyze, interpret, and present data Project: GP26
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stay clear zone in Automation, the area between the instrument or specimen processing and handling device and the automation hardware that must remain clear of any physical device, ensuring that there is adequate access by the user or service person to either system Project: AUTO01, AUTO02
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steady-state operating condition operating condition of a measuring instrument or measuring system in which the relation established by calibration remains valid even for a measurand varying with time (JCGM 200:2008) Project: ISO IEC Guide 99
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steatorrhea the presence of excessive fecal fat Project: C34
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steganography 1) the art and science of hiding information by embedding messages within other, seemingly harmless messages; 2) works by replacing bits of useless or unused data in regular computer files (such as graphics, sound, text, HTML, or even floppy disks) with bits of different, invisible information; 3) sometimes used when encryption is not permitted, or more commonly, steganography is used to supplement encryption Project: AUTO09 NOTE 1: This hidden information can be plain text, cipher text, or even images; NOTE 2: An encrypted file may still hide information using steganography, so even if the encrypted file is deciphered, the hidden message is not seen.
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step response time duration between the instant when an input quantity value of a measuring instrument or measuring system is subjected to an abrupt change between two specified constant quantity values and the instant when a corresponding indication settles within specified limits around its final steady value (JCGM 200:2008) Project: ISO IEC Guide 99
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steradian solid angle at the center of a sphere subtending a section on the surface equal in area to the square of the radius of the sphere Project: I/LA24 NOTE: A complete sphere comprises 4π steradians.
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sterilant an agent intended to destroy all microorganisms (viruses, vegetative bacteria, fungi, and large numbers of highly resistant bacterial endospores) on inanimate surfaces Project: M29
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sterile state of being free of all microorganisms Project: PRE05
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sterility complete absence of living microorganisms
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sterility assurance level an indication of the degree of sterility a product has after having gone through a sterilization process Project: QMS23 EXAMPLE: A sterility assurance value of 10−6 means that the probability of a microorganism surviving on an item subjected to treatment is less than one in 1 million.
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sterilization validated process used to render a product free from microorganisms (ISO 15190) Project: ISO 15190, M29, GP40, QMS23, QMS28 NOTE: Effectively killing all microbial life on inanimate surfaces, including bacterial spores.
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sterilization a procedure that kills all microorganisms, including bacterial spores Project: GP05
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sterilizer an agent, process, or device capable of the destruction of all microorganisms
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stock isolate isolate recovered from a clinical sample that has been retained, stored, or obtained from a culture collection (ISO 20776-2) Project: ISO 20776-2 NOTE: Stock isolates are usually included because they have known or rare resistance mechanisms, or are of a genus or species for which the antimicrobial agent is indicated but are not commonly isolated. Such organisms are unlikely to be available in fresh clinical isolates used in the evaluation (ISO 20776-2).
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stock solution initial solution used for further dilutions (ISO 20776-1) Project: ISO 20776-1
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stock solution of stain stable defined solution of one or more dyes at a higher concentration than that employed for staining [ISO/DIS 19001 (February 2002)] Project: ISO19001 (February 2002) NOTE: Stability refers to constant properties of the dye even in the presence of other dyes.
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Stokes’ law as used in this document, the observation by Sir George Stokes that fluorescence emission has a longer wavelength than the illuminating light that causes excitation. Stokes’ shift – The difference between the wavelength of the excitation maximum and the wavelength of the emission maximum of a fluorescer; NOTE: This may also be referred to in the possessive (Stokes’ law/shift), but Stokes’ law/shift is incorrect Project: I/LA24 NOTE: This may also be referred to in the possessive (Stokes’ law/shift), but Stokes’ law/shift is incorrect.
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Stokes’ law the law that states that the frequency of luminescence induced by radiation is usually less than the frequency of the radiation NOTE: This law is named after Sir G. Stokes.
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Stokes’ shift the difference between the wavelength of the excitation maximum and the wavelength of the emission maximum of a fluorescer
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stop-loss a variant that changes a termination or stop codon (TAG, TAA, or TGA) into one that codes for an amino acid Project: MM01
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storage conditions environmental parameters established by the manufacturer, describing how a product is to be stored Project: M50 NOTE: These parameters must be followed to ensure product claims are met.
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storage conditions manufacturer-recommended environmental conditions for storage of a product, stated on the product label or its instructions for use, which may include temperature, humidity, and light protection Project: EP25
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storage pool the contents of platelet granules (alpha, dense, and lysosomal) Project: H58
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strain a group of organisms of the same species, having a distinctive inborn or inherited tendency or characteristic but not usually considered a separate breed or variety Project: MM10
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strain populations of cells that arose from a single cell Project: M64
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strain a set of isolates that, as analyzed by a typing system, give the same typing result (ie, are “indistinguishable” from each other) and that can be distinguished (ie, are “different”) from other isolates of the same genus and species; such isolates are thereby inferred to be genotypically related to each other Project: MM11, MM24 NOTE 1: A single isolate with a distinctive typing result also represents a strain; NOTE 2: A strain is a descriptive subdivision of a species and is operationally dependent on the characteristics of the typing system; thus, a set of isolates representing a single strain in one typing system might be resolved into more than one strain by another system; NOTE 3: A group of organisms of the same species, having a distinctive inborn or inherited tendency or characteristic but not usually considered a separate breed or variety; NOTE 4: See also isolate.
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strategic national stockpile (SNS) large (approximately 150 000 lbs.), strategically-located caches of medical supplies and pharmaceuticals, designed for rapid airborne deployment to domestic sites suffering a major disaster, within 12 hours of formal request NOTES: a) Synonymous with "pushpack;" b) This term supercedes "National Pharmaceutical Stockpile." (http://www.dhs.gov/dhspublic/display?theme=15&content=327)
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strategy key element of the strategic prioritization phase of plans management that most broadly delineates how a clinical service organization can best satisfy a specific customer need Project: QMS06 NOTE 1: A strategy can be time-phased as short-, medium-, or long-range and might require staging for research, development, and/or implementation; NOTE 2: A policy.
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strategy action plan to set the direction for the coordinated use of resources through programs, projects, policies, processes, procedures, and organizational assets to advance future organization interests Project: QMS16, QMS21
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strategy action plan to set the direction for the coordinated use of resources to advance future business interest Project: QMS14, QMS25 NOTE 1: A strategy can be time-phased as short-, medium-, or long-range and might require staging for research, development, and/or implementation; NOTE 2: A policy.
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stratification the process of or result of separating a sample into several subsamples according to specified criteria, such as age groups, socioeconomic status, etc Project: GP45 NOTE 1: Stratifying the analysis of results may control the effect of confounding variables. For example, lung cancer is known to be associated with smoking. To examine the possible association between urban atmospheric pollution and lung cancer, controlling for smoking, the population may be divided into strata according to smoking status. The association between air pollution and cancer can then be appraised separately within each stratum; NOTE 2: Stratification is used not only to control for confounding effects but also as a way of detecting modifying effects. In this example, stratification makes it possible to examine the effect of smoking on the association between atmospheric pollution and lung cancer.
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stratification process of partitioning subjects or results by a factor other than that being directly studied Project: QMS12 EXAMPLE: Separating data for clean-catch urine culture contamination rate by age and/or sex.
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stream cipher an encryption algorithm that breaks plaintext into a stream of successive bits (or characters) and encrypts the n-th plaintext bit with the n-th element of a parallel key stream, thus converting the plaintext bit stream into a ciphertext bit stream (See block cipher) (RFC 2828) Project: AUTO09
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streamlined quality control the reduction of quality control for a commercial microbial identification system as compared to the requirements in the Clinical Laboratory Improvement Amendments regulations Project: M50, M52 NOTE 1: To allow for streamlined quality control, the manufacturer of the microbial identification system will specify the key indicator strains and reagents/substrates to be tested, as applicable. The manufacturer will also provide the expected quality control results for the indicator strains for each microbial identification system, based on historical data and ongoing quality assurance programs at the site of manufacture. The laboratory user may add but may not decrease the number of specific quality control organisms and/or reagents/substrates to be tested and reviewed, as recommended by the manufacturer for each lot number and shipment. Implementation of streamlined quality control by the user can only occur after the user has verified the performance of the test system in use; NOTE 2: To allow for streamlined quality control, the manufacturer of the microbial identification system will specify the key indicator strains and reagents/substrates to be tested, as applicable. The manufacturer will also provide the expected quality control results for the indicator strains for each microbial identification system, based on historical data and ongoing quality assurance programs at the site where the system is manufactured. The laboratory user may add but may not decrease the number of specific quality control strains and/or reagents/substrates to be tested and reviewed, as recommended by the manufacturer for each lot number and shipment. Implementation of streamlined quality control by the user can only occur after the user has verified the performance of the test system in use.
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stringency the degree of specificity in a DNA hybridization or annealing reaction Project: MM02, MM10, MM03, MM12, M55, MM01, MM24 NOTE 1: Stringency is adjusted by altering the salt concentrations in the buffer and/or adjusting the temperature of the reaction; for example, increasing the salt concentration decreases the stringency (more DNA will bind less specifically, allowing for more base-pair mismatches to occur); higher temperature increases the stringency (less DNA will bind more specifically); NOTE 2: Stringency considerations apply to all annealing steps in cDNA synthesis and amplification, as well as hybridization and wash conditions in detection; NOTE 3: Conditions can be designed to allow only perfect hybridization, or to tolerate a certain degree of mismatch; NOTE 4: Reduced stringency can be employed for specific applications such as those in which microarrays from one organism (eg, human) are used to study a related organism (eg, mouse); NOTE 5: Stringency is adjusted by altering the salt concentrations in the buffer and/or adjusting the temperature of the reaction; for example, increasing the salts decreases the stringency (more DNA will bind less specifically, allowing for more base-pair mismatches to occur); higher temperature increases the stringency (DNA will bind more specifically); NOTE 6: Conditions may be designed to allow only perfectly complementary hybridization, or to tolerate a certain degree of mismatch.
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subclass control an immunoglobulin of the same isotype (class or subclass) as the monoclonal antibody of interest, but without specificity for any known human antigens Project: H42, H43 NOTE: Most monoclonal antibodies used in flow cytometry are either immunoglobulin M, or various subclasses of immunoglobulin G (immunoglobulin G1, immunoglobulin G2a, immunoglobulin G2b, or immunoglobulin G3). This type of control is typically used to estimate nonspecific binding for antibody reagents of a given subclass.
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subclinical congenital hypothyroidism a biochemical pattern of slightly elevated thyroid-stimulating hormone levels accompanied by in-range thyroid hormone levels Project: NBS10 Source: Newborn Screening Glossary NOTE: See hyperthyrotropinemia.
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subculture a bacterial or fungal culture made from material derived from another culture (eg, the blood-broth mixture in blood culture bottles) or a culture made by transferring microorganisms to a fresh medium from a previous culture Project: M47 NOTE: This method is used to prolong the life of a particular strain when older cultures tend to degenerate.
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subgroup analysis an analysis in which the intervention effect is evaluated in a defined subset of the participants in the trial, or in complementary subsets, such as by sex or in age categories Project: GP45 NOTE: Sample sizes in subgroup analyses are often small and subgroup analyses therefore usually lack statistical power; they are also subject to the multiple comparisons problem.
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subject a person, either as an individual on whom or on whose specimen and investigational device is used or as a control, with disease or without disease, enrolled in an evaluation Alternate Term: proband Project: I/LA21 NOTE: An equivalent term is “proband.”
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sub–minimal inhibitory concentration effect any effect of an antimicrobial agent on a microorganism at concentrations below the antimicrobial agent’s minimal inhibitory concentration Project: VET02
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submultiple of a unit measurement unit obtained by dividing a given measurement unit by an integer greater than one (JCGM 200:2012) Project: ISO IEC Guide 99 EXAMPLE 1: The millimetre is a decimal submultiple of the metre (JCGM 200:2012); EXAMPLE 2: For a plane angle, the second is a nondecimalsubmultiple of the minute (JCGM 200:2012); NOTE: SI prefixes for decimal submultiples of SI base units and SI derived units are given in Note 5 of 1.16 (JCGM 200:2012).
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submultiple of a unit (of measurement) smaller unit of measurement that is formed from a given unit according to scaling conventions; EXAMPLE: one of the decimal submultiples of the metre is the millimetre
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subspecialty care providers individuals trained to provide specialized pediatric services, eg, endocrinology, metabolism, genetics, hematology, pulmonology, audiology, immunology, cardiology, and neurology Alternate Term: subspecialists Project: NBS03
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substance the entity identified or characterized
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substance concentration (mol/L) the amount of substance {mol} of the component divided by the volume of the system (IUPAC/IFCC1978-4.11) Project: VET03
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substance concentration mole per liter of the specified substance
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substance concentration of bicarbonate in plasma cHCO3- (P)
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substance concentration of total CO2 (ctCO2) the sum of the substance concentrations of each of the CO2 species in equilibrium with CO2 gas Project: C12 NOTE: This may be measured directly by measurement of carbon dioxide tension and pH, followed by application of the Henderson-Hasselbalch equation.
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substance content mole per kilogram of the specified substance
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substance fraction the number of mole per kilogram of the specified substance relative to the total mole per kilogram under consideration
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substance fraction the amount of substance {number of molecules} of the component divided by the amount of substance of all components in the system (IUPAC/IFCC1978- 4.13)
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substance ratio the number of moles per kilogram of the specified substance relative to the number of moles per kilogram of another substance under consideration
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substitution error (misread) information decoded by the bar code reader that is different from the information intended to be encoded in the bar code Project: AUTO14
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substrate a biochemically active ingredient used for identification that is incorporated in a microbial identification system and is acted upon and converted to a chemically different product Project: M50
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substrate a substance acted upon and converted to a chemically different product Project: NBS07 NOTE: In NBS07, methods using various substrates are described for measuring the activity of the lysosomal enzyme acid α-glucosidase.
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substrate plasma plasma from a person who is congenitally deficient in Factor VIII coagulant activity, an artificially depleted plasma, or another substrate material Project: H34
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substrate-chromogen a reagent commonly used in immunohistochemistry that contains both a substrate and a chromogen Project: H56 NOTE: When reacted with an appropriate enzyme, the substrate-chromogen produces a colored reaction product that specifically labels immunoreactive substances in cells and tissues.
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subtype a taxonomic term for a cluster of viral strains with phylogenetically related genetic sequences originating from a recent common ancestor Alternate Term: clade Project: M53
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succession planning identification and development of potential successors for key positions in an organization, through a systematic evaluation process and training Project: QMS16
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sulfhemoglobin (SulfHb) a dyshemoglobin (nonoxygen-carrying hemoglobin derivative) formed by incorporation of a sulfur atom bound to a pair of pyrrol carbon atoms at the periphery of a chlorin ring formed by saturation of that beta-beta double bond of the corresponding protoporphyrin IX. See also hemoglobin Alternate Term: SulfHb Project: C25
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superantigen a molecule that can nonspecifically stimulate T-cells by binding to domains outside the antigen-specific T-cell receptor Project: I/LA26
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superficial lesion See superficial mass Alternate Term: superficial mass Project: GP20
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superficial mass situated near the surface Alternate Term: superficial lesion Project: GP20 NOTE: It is palpable.
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supplemental (not routine) test test that detects susceptibility or resistance to an antimicrobial agent or drug class by a method other than routine disk diffusion or broth or agar dilution and does not need additional tests to confirm susceptibility or resistance Project: M02, M07, VET01 NOTE 1: Some supplemental tests identify a specific resistance mechanism; NOTE 2: A supplemental test may be required or optional for reporting clinical results.
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supplemental test assay used in a multitest algorithm after an initial test to verify or clarify the result of the initial test Project: M53
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supplier organization or person that provides a product or a service (modified from ISO 9000) Project: QMS01, GP26 Source: Quality Glossary EXAMPLES: Producer, distributor, retailer, or vendor of a product, or a provider of a service or information (modified from ISO 9000); NOTE 1: A supplier can be internal or external to the organization (modified from ISO 9000); NOTE 2: In a contractual situation, a supplier is sometimes called a “contractor” (modified from ISO 9000).
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supply chain the network created to manage product or service movement from supplier to customer Project: QMS21
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suppressed-zero scale scale whose scale range does not include the value zero
EXAMPLE scale of a clinical thermometer
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suppression reporting withholding some antimicrobial susceptibility test results from the final report provided to clinical end users, in part, to support antimicrobial stewardship efforts Project: M39 NOTE: Both cascade reporting and selective reporting represent types of antimicrobial result suppression.
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suprapubic specimen a urine specimen collected by aspiration from the distended bladder through the abdominal wall Project: NRSCL8
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supravital dye a dye used to stain living cells already removed from an individual Project: H44
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surge capacity in GP36, the reserve ability to conduct testing in a situation when normal laboratory functions are so overwhelmed that they may compromise testing accuracy and/or timeliness Project: GP36 NOTE 1: Such testing could exist within the institution or be shifted to location(s) off site or outside the institution; NOTE 2: The term is best used to define reserve ability for a specific test or tests, but can also be used in the general sense; NOTE 3: The term implies that there is mutual understanding among testing facilities such that specific conditions are defined, including the sharing of testing equipment, reagents, and/or testing personnel.
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surrogate agent test test performed with an agent that replaces a test performed with the antimicrobial agent of interest and is used when the agent of interest cannot be tested due to availability or performance issues (eg, surrogate agent performs better than the agent of interest) Project: M02, M07, VET01
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surrogate material material used as a substitute for biologic material without having all of the functional characteristics of such materials Project: H26
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surrogate matrix native matrix that has been altered for routine use Project: C64 NOTE 1: Surrogate materials are used as substitutes for biological material without having all the functional or constituent characteristics of native matrix (eg, artificial matrix, spiked matrix, diluted matrix, stripped matrix); NOTE 2: Surrogate matrix can be true matrix from a species other than the one for which a measurement system is developed (eg, horse serum used as surrogate matrix for calibrators in an assay for a human protein).
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surrogate outcome measures in clinical trials, a surrogate end point (or marker) is a measure of effect of a certain treatment that may correlate with an actual clinical end point but does not necessarily have a guaranteed relationship NOTE: Surrogate markers are used when the primary end point is undesired (eg, death), or when the number of events is very small, thus making it impractical to conduct a clinical trial to gather a statistically significant number of end points.
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surrogate peptide peptide selected to represent a specific proteoform or proteoforms as defined by the measurand Project: C64
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surrogate sample material or combination of materials used as a substitute for body fluid or tissue taken for examination from a single human subject to study the characteristic of interest. Project: EP35, EP39
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surveillance systems or approaches to collecting, collating, and analyzing individual patient or collective laboratory or symptomatic data to permit early detection of an unusual type, number, or cluster of syndromes or diseases Project: GP36 NOTE: Approaches that rely upon symptoms are called “syndromic” surveillance, and those that rely upon agent identification, eg, culture results, are “traditional” surveillance.
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surveillance (prospective) ongoing collection of epidemiological data, with real-time analysis Project: POCT16 NOTE 1: Mortality surveillance systems usually rely on home visitors who record deaths in households on a weekly basis; NOTE 2: The systematic ongoing collection, collation, and analysis of data for public health purposes and the timely dissemination of public health information for assessment and public health response as necessary.
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surveillance isolates organisms obtained from cultures of specimens that are collected for the purpose of determining if a patient is harboring (or colonized with) a particular organism and are not from specimens that are obtained as part of the clinical evaluation of a patient’s illness Project: M39 NOTE: For example, rectal cultures are sometimes performed to determine if a patient is colonized with vancomycin-resistant enterococci or carbapenem-resistant gram-negative organisms, and nares cultures may be performed to determine if a patient is colonized with methicillin (oxacillin)-resistant Staphylococcus aureus.
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survey an investigation in which information is systematically collected Project: GP45 NOTE 1: A population survey may be conducted by face-to-face inquiry, by self-completed questionnaires, by telephone, by postal service, or in some other way; each method has its advantages and disadvantages; NOTE 2: The generalizability of results depends upon the extent to which those surveyed are representative of the entire population.
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survey a series of proficiency testing samples that are sent to participating laboratories to assess their ability to obtain the correct analytical results Project: MM14
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susceptible (S) for breakpoints, bacterial strain inhibited in vitro by a concentration of an antimicrobial agent that is associated with a high likelihood of therapeutic success (ISO 20776-1) Project: ISO 20776-1, ISO 20776-2 NOTE 1: Bacterial strains are categorized as susceptible by applying the appropriate breakpoints in a defined phenotypic system (ISO 2076-1); NOTE 2: This breakpoint can be altered due to changes in circumstances (e.g., changes in commonly used drug dosages, emergence of new resistance mechanisms) (ISO 20776-1).
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susceptible antimicrobial susceptibility test interpretive category a category that implies that isolates are inhibited by the usually achievable concentrations of antimicrobial agent when the recommended dosage is used for the site of infection
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susceptible antimicrobial susceptibility test interpretive category 1) for critical concentration, a level of susceptibility that is not significantly different from that of wild-type strains from patients who have not been treated with the drug, so that the strain is likely to show clinical responsiveness to the drug; 2) for minimal inhibitory concentration, an interpretive category that implies that an infection due to the isolate may be appropriately treated with the dosage of an antimicrobial agent recommended for that type of infection and infecting species, unless otherwise indicated, given the levels attainable with the agent at the site of infection.
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susceptible antimicrobial susceptibility test interpretive category a category that implies that an infection due to the isolate may be appropriately treated with the dosage of an antimicrobial agent recommended for that type of infection and infecting species, unless otherwise contraindicated
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susceptible antimicrobial susceptibility test interpretive category a category that implies that an infection due to the isolate may be successfully treated with the normal dosage regimen of an antimicrobial agent recommended for that type of infection and infecting species, unless otherwise indicated Project: VET05, VET04
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susceptible breakpoint the highest minimal inhibitory concentration or the smallest zone diameter value for which the interpretive category is considered susceptible Project: M39 NOTE: See interpretive category.
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susceptible-dose dependent antimicrobial susceptibility test interpretive category a category that includes isolates with antimicrobial agent minimal inhibitory concentrations (MICs) that approach usually attainable blood and tissue levels and for which response rates may be lower than for susceptible isolates
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susceptible-dose dependent antimicrobial susceptibility test interpretive category the “susceptible-dose dependent” category implies clinical efficacy when higher than normal dosage of a drug can be used and maximal possible blood level achieved
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suspension array technology as used in this document, the use of microspheres in suspension as the solid phase of ligand binding assays Project: I/LA24 NOTE: Such suspensions are usually analyzed by flow cytometry and are often multiplexed, ie, they contain multiple populations of microspheres identified by unique fluorescent or light scatter properties that can be differentiated in a single analytical pathway.
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suspension-bead microarray a three-dimensional array that uses microparticles (beads) as the solid support for the binding reaction and flow cytometry or charge-coupled device imaging for bead and associated target detection Project: MM24
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sustainability ability to maintain or support an activity or process over a long period of time
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sweat chloride test consists of stimulating sweat by pilocarpine iontophoresis; quantitative collection onto gauze, filter paper, or microbore tubing; and quantitative analysis of chloride concentration Project: NBS05 NOTE: The analysis of sweat chloride is used to confirm the diagnosis of cystic fibrosis.
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SWOT analysis an assessment tool used to analyze a process or system’s major strengths, weaknesses, opportunities, and threats Project: QMS14
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SWOT analysis a strategic planning method used to evaluate the Strengths, Weaknesses, Opportunities, and Threats involved in a project or in a business venture. It involves specifying the objective of the business venture or project and identifying the internal and external factors that are favorable and unfavorable to achieving that objective
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symbol visually perceptible figure used to transmit information independent of language Alternate Term: graphical symbol Project: ISO CD 18113-1, ISO CD 18113-2, ISO CD 18113-3
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symbol in automation, a combination of bar code characters, including start and stop or postamble characters, quiet zones, data elements, and check characters, which form a complete reading entity Project: AUTO01, AUTO07, AUTO02, AUTO12, AUTO14
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symbol of a unit (of measurement) conventional sign designating a unit of measurement
EXAMPLES
a) m is the symbol for metre;
b) A is the symbol for ampere.
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symbol of a unit a conventional sign designating a unit of measurement (VIM93-1.8)
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symbology any one of many unique bar code systems (linear or two-dimensional) that can be used in different applications, including clinical and anatomic pathology laboratories Project: AUTO14 NOTE: A few examples of different linear bar code symbologies are Interleaved 2 of 5, Code 39, Code 128, and UPC. Two-dimensional symbologies can be either of the stacked type (eg, Code 49, Code 16K, PDF417) or matrix type (eg, Aztec, Data Matrix)
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syncope (fainting) a loss of consciousness over a short period of time, caused by a temporary lack of oxygen in the brain Project: PRE02
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syncytium a type of cytopathic effect resulting from the fusion of adjacent cells Project: M41 NOTE: Also referred to as a multinucleated giant cell.
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syngeneic a characteristic of animals with an identical genetic constitution Project: DI01
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synonymous mutation a nucleotide change that does not result in a different amino acid being incorporated into the polypeptide chain NOTE: Also referred to as a “silent” nucleotide change.
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synonymous variant a nucleotide change that does not result in a different amino acid being incorporated into the polypeptide chain Project: MM01 NOTE: Also referred to as a “silent” nucleotide change.
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synovial fluid fluid normally present in the joint space that can be increased in amount usually due to inflammatory or septic causes Alternate Term: joint fluid Project: C49 NOTE: The removal of such fluid is performed by arthrocentesis.
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system set of interrelated or interacting elements (ISO 9000) Project: ISO 9000, EP18, EP23, M52 NOTE: In M52, an instrument or product that provides microbial identification and/or antimicrobial susceptibility testing results when used according to the manufacturer’s instructions. The system normally includes panels or cards, and materials for setup, inoculation, and incubation of these disposable devices. It may also incorporate software for result compilation and interpretation as well as data storage.
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system 1) people, machines, and methods organized to accomplish a set of specific functions (ANSI/IEEE Std. 100-2000); 2) a composite, at any level of complexity, of personnel, procedures, materials, tools, equipment, facilities, and software; the elements of this composite entity are used together in the intended operational or support environment to perform a given task or achieve a specific purpose, support, or mission requirement (MIL-STD-882C) Project: AUTO08
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system the combination of processes and items that performs a complete task
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system part or phenomenon of the perceivable or conceivable world consisting of a demarcated arrangement of a set of elements and a set of relationships or processes between these elements Project: C51 NOTE: The concept “system” is used both in the sense of a phenomenon, body, or substance, such as a person or a blood sample, carrying a property, and in the combination of measuring instruments, reagents, and supplies constituting a measuring system (IUPAC § 3).
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system sum total of all organizational resources that are part of the delivery of care to patients NOTE: The system includes staff, funds, information, supplies, transport, communications, and overall guidance and direction.
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system accuracy closeness of agreement of a set of representative measurement results from a measuring system and their respective reference values (ISO 15197) Project: ISO 17593 NOTE 1: The term "accuracy of measurement," when applied to a set of meaurement results, involves a combination of random error components and a common systematic error or bias component (modified from ISO 157593); NOTE 2: Reference values are assigned by a measurement procedure traceable to a reference measurement procedure of higher order (ISO 15197); NOTE 3: System accuracy may be expressed as the interval that encompasses 95% of the differences observed between the results of the system being evaluated and their reference values. This interval also includes measurement uncertainty from the measurement procedure used to assign the reference values.
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system accuracy closeness of agreement between a set of representative results from a measuring system and their respective reference values (ISO 15197) Project: POCT06 NOTE 1: System accuracy describes the ability of a glucose monitoring system to produce measurement results that agree with true glucose values when the system is used as intended (ISO 15197); NOTE 2: The term accuracy, when applied to a set of measured values, involves a combination of random error components and a common systematic error or bias component (ISO 15197); NOTE 3: Reference values are assigned by a measurement procedure traceable to a reference measurement procedure of higher order (ISO 15197).
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system audit documented activity performed to verify, by examination and evaluation of objective evidence, that applicable elements of the system are appropriate and effective and have been developed, documented, and implemented according to and in conjunction with specified requirements Project: QMS15 NOTE: A system audit studies everything within the system (ie, the processes, products, services, and supporting groups, such as purchasing, customer service, design engineering, order entry, waste management, and training).
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system integrity the quality that a system has when it can perform its intended function in an unimpaired manner, free from deliberate or inadvertent unauthorized manipulation (NCSC-TG-004-88) Project: AUTO09
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system of quantities set of quantities together with a set of noncontradictoryequations relating those quantities (JCGM 200:2008) Project: ISO IEC Guide 99 NOTE: Ordinal quantities, such as Rockwell C hardness, are usually not considered to be part of a system of quantities because they are related to otherquantities through empirical relations only (JCGM 200:2012).
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system of quantities set of quantities, in the general sense, among which defined relationships exist (VIM93) Project: VIM93
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system of units set of base units and derived units, together with their multiples and submultiples, defined in accordance with given rules, for a given system ofquantities (JCGM 200:2008) Project: ISO IEC Guide 99
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system of units (of measurement) set of base units, together with derived units, defined in accordance with given rules, for a given system of quantities (VIM93); EXAMPLES: a) International System of Units, Si;b) CGS system of units Project: VIM93
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systematic having, showing, or involving a method, plan or pattern
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systematic difference the mathematical difference between the mean of measurement procedure results for the primary specimen and the mean of measurement procedure results for the candidate specimen Project: EP35 NOTE 1: The systematic difference is the difference of biases between the results; NOTE 2: The systematic difference should be less than a fraction of the allowable bias.
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systematic error mean that would result from an infinite number of measurements of the same measurand carried out under repeatability conditions minus a true value of the measurand (VIM93) Project: I/LA21 NOTE 1: Systematic error is equal to error (of measurement) minus random error (VIM93-3.14); NOTE 2: Like true value, systematic error and its causes cannot be completely known (VIM93-3.14); NOTE 3: For a measuring instrument, see “bias.” (VIM93-3.14).
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systematic error a component of error that, in the course of a number of analyses of the same measurand, remains constant or varies in a predictable way
(Linnet K, Boyd JC. Statistical methodologies in laboratory medicine: analytical and clinical evaluation of laboratory tests. In: Burtis CA, Bruns DE, eds. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 7th ed. Elsevier; 2023:12.) Project: EP46 NOTE 1: A reference quantity value for a systematic measurement error is a true quantity value, or a measured quantity value of a measurement standard of negligible measurement uncertainty, or a conventional quantity value (JCGM 200:2012); NOTE 2: Systematic measurement error, and its causes, can be known or unknown. A correction can be applied to compensate for a known systematic measurement error (JCGM 200:2012); NOTE 3: Systematic measurement error equals measurement error minus random measurement error (JCGM 200:2012); NOTE 4: “Measurement bias” is an estimate of “systematic measurement error.”
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systematic error of measurement See systematic error Alternate Term: systematic error; systematic measurement error Project: C51
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systematic measurement error See systematic error Alternate Term: systematic error of measurement; systematic error Project: C51
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systematic review a concise summary of the best available evidence that addresses sharply defined clinical questions Project: GP45 NOTE 1: Systematic reviews differ from other reviews, often termed narrative reviews in several ways; systematic reviews address a focused clinical question, use an explicit search strategy applied to comprehensive sources, uniformly apply criteria for the selection of sources, use rigorous critical appraisal to make evidence-based inferences; NOTE 2: Systematic reviews that use quantitative methods to summarize evidence are termed “meta-analyses.”
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systemic inflammatory response syndrome a physiologic state believed to be triggered by systemic activation of the innate immune response NOTE: Under the current definition, systemic inflammatory response syndrome is considered to be present when patients have more than one of the following clinical and/or laboratory findings: body temperature >38°C or <36°C; heart rate >90/minute; hyperventilation evidence by respiratory rate >20/minute or PaCO2 <32 mm Hg; and white blood cell count >12 000 cells/µL or <4 000 cells/µL.
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system-specified value a value assigned to a calibrator intended or recommended for use only with analytical systems that are specified
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tabletop exercise instrument intended to stimulate discussion of various issues regarding a hypothetical situation Project: GP36 NOTE 1: They can be used to assess plans, policies, and procedures or to assess types of systems needed to guide the prevention of, response to, or recovery from a defined incident; NOTE 2: During a tabletop exercise, senior staff, elected or appointed officials, or other key personnel meet in an informal setting to discuss simulated situations; NOTE 3: Tabletop exercises are typically aimed at facilitating understanding of concepts, identifying strengths and shortfalls, and/or achieving a change in attitude; NOTE 4: Participants are encouraged to discuss issues in depth and develop decisions through slow-paced problem-solving rather than the rapid, spontaneous decision-making that occurs under actual or simulated emergency conditions; NOTE 5: Tabletop exercises can be breakout (ie, groups split into functional areas) or plenary (ie, one large group).
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tactics activities and tasks to complete to meet each quality objective
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tamoxifen an antagonist of the estrogen receptor in breast tissue Project: MM19
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tandem conjugate a chemical complex of two fluorochromes arranged so that some of the energy emitted from the first is used to excite the second Project: H42, H43, H52 NOTE: In practice, the most common tandem conjugates link phycoerythrin or other fluorochromes, which can be excited at 488 nm, to a fluorochrome that normally is excited at a longer wavelength than 488 nm, and that emits in the far red part of the spectrum. Examples of tandem conjugates are PE-Cy5, PE-Cy7, and APC-Cy7.
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tandem mass spectrometry (or tandem mass spectrometer) a technique (instrument) in which an ion at a particular m/z value is isolated in one mass analyzer, caused to undergo fragmentation, and the product ions are separated and detected in a second mass analyzer Project: C50 NOTE 1: Further stages of mass selection and subsequent fragmentation of product ions from a tandem mass spectrometry experiment may also be performed. These are typically referred to as MS3 (MS/MS/MS), MS4...MSn, depending on the number of generations of product ions; NOTE 2: When the term tandem mass spectrometry is used without qualification in this document, it most likely refers to the tandem mass spectrometers using quadrupole analyzers; NOTE 3: The use of the abbreviation TMS or “tandem mass” is strongly discouraged.
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tandem mass spectrometry the acquisition and study of the spectra of the electrically charged products or precursors of m/z-selected ion or ions, or of precursor ions of a selected neutral mass loss. Tandem mass spectrometry can be accomplished using beam instruments incorporating more than one analyzer (tandem mass spectrometry in space) or in trap instruments (tandem mass spectrometry in time) (IUPAC 2006) Project: C43
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tandem mass spectrometry a technique in which an ion at a particular m/z value is isolated in one mass analyzer, caused to undergo fragmentation, and the product ions are separated and detected in a second mass analyzer Project: NBS04, NBS09 NOTE: The use of the abbreviation “TMS” for “tandem mass spectrometry” is strongly discouraged.
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target the area of the nucleic acid to be detected or amplified for detection or analysis (also called “template”) Project: MM02, MM13, MM10, MM12, MM22, MM24 NOTE: As used in microarrays, the target is the molecule in solution (new use) not attached to the microarray support (original use).
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target in expression analysis, the RNA sample or gene of interest that is being assayed Project: MM16 NOTE: For microarrays, the target is labeled and hybridized to the array. In QRT-PCR, the target RNA is labeled and hybridized.
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target a specific sequence of bases within a portion or segment of a nucleic acid molecule to be detected or amplified by analysis. Project: MM01
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target a specified number that management sets for achieving or exceeding a metric (ie, desired performance) Project: QMS12
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target condition See condition of interest
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target locus a specific position on a chromosome that the probe is intended to detect Project: MM07 NOTE: Probes may be labeled with fluorescent, radioactive, chemiluminescent, or enzymatic markers to permit visualization and quantitation of their binding to target DNA.
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target measurement uncertainty measurement uncertainty specified as an upper limit and decided on the basis of the intended use of measurement results (JCGM 200:2008) Alternate Term: target uncertainty Project: ISO IEC Guide 99
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target plate metal (usually stainless steel), nondisposable support on which spots are applied for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis Project: M58
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target population individuals for whom the test is intended Alternate Term: intended use population Project: MM09, MM17 NOTE: Group of subjects with genotypes and phenotypes representative of the population.
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target population the group of persons about whom an investigator intends to make inferences about the validity of study findings Project: GP45 NOTE: The target population may consist of all persons residing in a geographic area, persons with specific demographic characteristics, clinical characteristics, persons who receive services at specific source, or who have specific arrangements for financing or organization of care.
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target population specific populations for which measurement procedures are designed to be used Alternate Term: intended-use population Project: EP19 NOTE 1: The intended use and validation criteria are determined by the intended-use population, which may be defined in terms of age, sex, existence of comorbidities, and other issues; NOTE 2: Some test methods are designed for very specific populations, eg, newborn screening or prediction of inheritance risk of an inborn metabolic disease.
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target sequence area of nucleic acid to be detected and sequenced Project: MM09
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target slide disposable support on which spots are applied for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis Project: M58
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target value the assigned measurand content for a material to which a laboratory should compare its own measurement results Project: EP15, QMS24 NOTE 1: Depending on the particular material, the target value may be assigned by a reference material manufacturer or from the results of a multilaboratory study; NOTE 2: For quantitative tests, either the mean of all participant responses (after the removal of outliers determined by valid statistical approaches) or the mean established by reference methods acceptable for use by the proficiency testing provider; NOTE 3: The term “target value” is subsumed by the more general term “assigned value.”
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targeted testing the use of analytical techniques and methods that permit the identification of defined analytes or compounds using a definitive method Project: C63 NOTE: The term does not distinguish between the purpose of the method, eg, qualitative vs quantitative, screening vs confirmation.
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targeted therapy a treatment or medication that blocks the growth of cancer cells by interfering with specific targeted molecules needed for carcinogenesis and tumor growth, as opposed to traditional chemotherapy treatments that interfere with rapidly dividing cells Project: MM19, MM26 NOTE: Targeted cancer therapies can be more effective than current treatments and less harmful to normal cells.
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targeted variant analysis either allele-specific variant analysis or testing for either two or more specific variants in a gene Project: MM19
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target-specific polymerase chain reaction polymerase chain reaction method in which one or both primers of the pair are designed to amplify a specific sequence to determine the presence or absence of a target and/or differentiate a specific target within a mixture of target nucleic acids Project: MM22
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target-specific primer extension a solution-based, sequence-specific enzymatic reaction technology that can be used to assay multiple targets in a single tube; an enzymatic DNA polymerization reaction that determines the presence of a specific target Project: MM22
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tartrate resistant acid phosphatase isoform 5b acid phosphatase secreted by the osteoclasts whose phosphatase activity is not inhibited by L+-tartrate Project: C48 NOTE: Does not contain sialic acid, which distinguishes it from the macrophage-derived isoform tartrate resistant acid phosphatase isoform 5a
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task planning element that delineates the specific “who, what, how, and when” to accomplish a specific objective Project: QMS06, QMS14, QMS16, QMS03
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task planning element that delineates the specific “who, how, and when” to accomplish a specific objective
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taxon any named group(s) of organisms Alternate Term: taxa Project: MM18
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T-cell receptor the receptor that confers antigen specificity on T-cells; it recognizes peptides complexed with major histocompatibility complex proteins Project: I/LA26
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T-cell receptor excision circle a circular DNA structure that is formed during rearrangement of the T-cell receptor gene Project: NBS06 NOTE: Different species of T-cell receptor excision circle are formed during the sequential rearrangements that result in a T-cell receptor. The T-cell receptor delta REC-Psi J alpha rearrangement signal joint, which is produced by rearrangements that result in the formation of the alpha/beta T-cell receptor, is used to screen newborns for severe combined immunodeficiency.
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T-cells (T lymphocytes) one of the two major populations of lymphocytes that display antigen-specific receptors and are involved in cell-mediated immunity, cytotoxicity, and immune regulation Project: NBS06 NOTE: T-cell progenitors produced in bone marrow differentiate and mature in the thymus. During this process, the T-cell progenitors rearrange the regions of their genome containing variable and constant region genes to form sequences that code for the two peptides of their antigen-specific receptors (the T-cell receptor).
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t-distribution (student’s distribution) {a parametric}probability distribution of a continuous random variable (ISO 3534-1/93-1.40) Project: ISO 3534-1 NOTE: The quotient of two independent random variables, the numerator of which is a standardized normal variable, and the denominator of which is the positive square root of the quotient of a X 2 {chi-squared} random variable and its number of degrees of freedom, n, is a Student’s distribution with n degrees of freedom (ISO 3534-1/93-1.40).
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Team Management Program an anticipatory team building process that ensures the most effective and efficient organizational decision-making
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technical area space in a medical laboratory allocated for the preparation or examination of samples Project: ISO15190 (March 2002)
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technical error an error directly attributable to actions of laboratory personnel in performance of a test that leads to an unacceptable PT result NOTE: Examples include mispipetting and morphologic misinterpretation.
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technical expert person who provides specific knowledge or expertise to the audit team (ISO 9000, ISO 19011) Project: QMS15 NOTE 1: Specific knowledge or expertise relates to the organization, activity, process, product, service, discipline to be audited, or language or culture (modified from ISO 9000, ISO 19011); NOTE 2: Also called a “subject matter expert.”
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technical validation the process by which a laboratorian accepts a single observation or a set of observations that has been produced either with a manual technique or an automated one, generally under his or her control Project: AUTO16 NOTE: Technical validation ensures that observations have been obtained in conformance with defined laboratory procedures and have satisfied quality control and other technical validation criteria.
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template a metal or plastic gauge that guides the length and depth of the bleeding time incision Project: H45
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template the portion of nucleic acid that acts to provide sequence information for the synthesis of a new strand of DNA or RNA Project: MM10, MM18, MM22, MM09, MM24
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template design, mold, or pattern of an item or group of items that serves as a basis or guide for designing or constructing similar items Project: QMS02
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temporal accuracy See the definition of accuracy
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tension See partial pressure
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tension of CO2 (PCO2) the partial pressure of carbon dioxide, in blood, water, buffer, or gas NOTE: The partial pressure is in direct proportion to the substance concentration.
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terminal deoxynucleotidyl transferase a nuclear enzyme found in immature cells, principally of the lymphoid lineage, but under some circumstances, in blast cells of myeloid lineage Project: H43
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terminal subculture a subculture taken from the blood-broth mixture in blood culture bottles at the end of the routine incubation and testing period Project: M47
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terrorism unlawful use of force and violence against persons or property to intimidate or coerce a government, the civilian population, or any segment thereof, in furtherance of political or social objectives Project: GP36
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test determination according to requirements for a specific intended use or application (ISO 9000) Project: ISO 9000, EP18, EP23
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test in the clinical laboratory, a qualitative, semiqualitative, quantitative, or semiquantitative procedure for detecting the presence of, or measuring the quantity of an analyte Project: NRSCL8
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test in medicine, an examination or procedure for determining the presence or absence of a particular condition Project: NRSCL8
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test as used in CLSI document I/LA28, a test encompasses the total test concept of the performance immunohistochemistry inclusive of performance of the assay, interpretation, and reporting results Project: I/LA28
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test an operation performed in a laboratory or at the point of care, manually or on an analyzer or with the help of a device, instrument, or system, to produce one or more observations (ie, results) Project: AUTO16 NOTE: Technical validation ensures that observations have been obtained in conformance with defined laboratory procedures and have satisfied quality control and other technical validation criteria.
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test case description of a program, function, requirement, or condition being tested, the data to be entered, and the outcome expected Project: AUTO13, I/LA33 NOTE 1: Documentation specifying inputs, predicted results, and a set of execution conditions for a test item; NOTE 2: A synonym is test case specification.
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test condition recipient reagent tested under normal operating conditions with steps taken to deliberately increase the potential for a carryover effect Project: EP47 NOTE: The recipient reagent is used to establish the response in the presence of a source reagent which is added to increase the potential for significant carryover.
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test design documentation specifying the details of the test approach for a software feature or combination of software features and identifying the associated tests (modified from IEEE definition) Project: I/LA33
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test life phases model the concept that every test method has a series of phases that should be followed from inception through implementation until retirement Project: EP19, EP45 NOTE: Similarly, phases should be followed to demonstrate that the test method performs acceptably in the hands of the end-user laboratory. The model terminates when the test method is retired by the end user.
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test manufacturers commercial developers and producers of the tests used in clinical laboratories Alternate Term: reagent manufacturers Project: MM14 NOTE 1: Though not directly involved in proficiency testing/external quality assessment, their products are assessed indirectly (and in some regards directly) by these programs and the test materials in the programs; NOTE 2: Medical laboratories are considered test/reagent manufacturers of laboratory-developed tests.
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test method the method (ie, either the routine laboratory method or automated method) that is compared with the reference method Project: H20, M02, M07, VET01
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test method detailed description of a measurement according to one or more measurement principles and to a given measurement method, based on a measurement model and including any calculation to obtain a measurement result Project: EP19, EP45 NOTE 1: A qualitative test method reports nominal values, eg, the presence or absence of the analyte without quantification; NOTE 2: A quantitative test method generates a spectrum of signal responses that are directly proportional to the measurand levels. If the analyte preparations with known concentrations are available for calibration, the actual concentration of the analyte can be determined; NOTE 3: A semiquantitative test method is essentially a qualitative test method with an additional option for a response range (degree of positivity, dilution to which positive results are obtained, or comparison to a color chart), and could use an ordinal scale; NOTE 4: For CLSI EP19/CLSI EP47, test method includes the hardware, software, reagents, calibrators, and any other items needed to obtain a medically relevant result.
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test mnemonics short, understandable contractions for test names Project: AUTO01, AUTO02
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test plan documentation specifying the scope, approach, resources, and schedule of intended testing activities. It identifies test items, the features to be tested, the testing tasks, responsibilities required, resources, and any risks requiring contingency planning Project: I/LA33 NOTE: See also test design and validation protocol.
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test plasma plasma (from a patient or unknown source) that is analyzed by a specific laboratory test Project: H30, H54
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test reagent recipient reagent tested under normal operating conditions with preceding measurement on a source reagent to deliberately increase the potential for carryover Project: EP47 NOTE: The recipient sample is used to quantify any carryover effect.
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test strip unit-use physical medium containing the reagent for a specific test Project: POCT07, POCT17, POCT13
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test system a unit or device used to measure or assess the presence or absence of a particular substance, or to quantitate that substance, found in blood or body fluids Project: POCT04, M55 NOTE: A test system includes instructions and all of the instrumentation, equipment, reagents, and/or supplies needed to perform an assay or examination and generate test results.
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test system a combination of thromboplastin, coagulation instrument, and technique used for prothrombin time determination Project: H54
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test system refers to a coagulation testing system that includes the analyzer, test method, test reagents, control material, calibrators, and buffers, which together contribute to an assay in order to provide results Project: H48
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test system a unit or device used to measure or assess the presence or absence of a particular substance, or to quantify that substance, found in blood or body fluids Project: MM22, MM03 NOTE: A test system includes instructions and all of the instrumentation, equipment, reagents, and/or supplies needed to perform an assay or examination and generate test results.
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test system system that includes instructions and all the instrumentation, equipment, reagents, and/or supplies needed to perform an assay or examination and generate test results Project: M02, M07, VET01
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test tube See specimen collection container Project: AUTO02, AUTO12
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testability 1) the degree to which a system or component facilitates the establishment of test criteria and the performance of tests to determine whether those criteria have been met; 2) the degree to which a requirement is stated in terms that permit establishment of test criteria and performance of tests to determine whether those criteria have been met (IEEE 610.12-1990) Project: AUTO08
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testing platform an entire system for which a measurand is detected or quantified. The system can include a specimen processing system, sample extraction, nucleic acid isolation, and amplification/detection Project: MM19
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testing sensitivity the minimal percentage of cells with a given signal pattern that can be detected by the FISH test
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testing site the physical location where testing is performed Project: H49
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testing system includes the entirety of the testing process, including instrument, sample, personnel, reagents, supplies, and procedures NOTE: It also includes such attributes (method characteristics) as sample type, testing temperature, humidity, etc.
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tetramer See major histocompatibility complex tetramer Project: I/LA26
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tetranucleotide frequency average enumeration of nucleotide tetramers that capture species-specific characteristics of nucleotide composition Project: M64
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thalassemia a condition resulting from reduced or absent synthesis of one or more of the globin chains or occurring when a structurally abnormal hemoglobin is synthesized at a reduced rate (eg, hemoglobin E and hemoglobin Constant Spring) Project: NBS08
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therapeutic administration of an antimicrobial to an animal, or group of animals, which exhibit frank clinical disease
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therapeutic antibodies in this setting, an immunosuppressive drug containing antibodies that affect the function of immunocompetent cells Project: ILA29
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therapeutic concentration concentration of a drug that is effective in producing a desired medical effect Project: EP07
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therapeutic drug monitoring a branch of clinical chemistry that specializes in the measurement of medication levels in blood. Its main focus is on drugs with a narrow therapeutic range, eg, drugs that can easily be under- or overdosed Project: MM19
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therapy administration of an antimicrobial to an animal, or group of animals, which exhibits frank clinical disease
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thermal cycler an automated, programmable instrument used to repetitively heat and cool a set of reaction tubes to promote DNA replication, denaturation, and hybridization in the polymerase chain reaction Project: MM01, MM10, MM12, MM24
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thermally dimorphic having two morphological forms, often at different temperatures Project: M54
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thermodynamic the branch of physics concerned with the conversion of different forms of energy; it is the study of the effects of work, heat, and energy on a system Project: GP28
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thermolabile easily degraded or subject to loss of characteristic properties as a result of exposure to heat. Highly thermolabile substances can rapidly degrade at room temperatures Project: PRE04
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thin film membrane a reverse osmosis membrane constructed of a thin film of polyamide materials Project: GP40
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third-tier screen (for newborn screening) additional assay, physiological measurement, or assessment, performed as a third step in a laboratory screening algorithm on a small subset of newborns, that uses the initial screening specimen (ie, specimen re-collection not necessary) when first- and second-tier screening results are out of range Alternate Term: third-tier screening; third-tier testing Project: NBS09 Source: Newborn Screening Glossary NOTE 1: A third-tier screening test might define the final, reportable result or might be used to provide additional relevant information to health care providers; NOTE 2: In newborn screening, third-tier testing is typically molecular, usually involving gene sequencing or multigene panels; NOTE 3: See laboratory screening algorithm, screening test, first-tier screen, and second-tier screen.
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thixotropic separator gel inert material that undergoes a temporary change in viscosity during centrifugation Project: GP39, GP34 NOTE: It has a density intermediate to cells/clot and plasma/serum.
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thixotropic separator gel in blood collection, an inert material, with a density intermediate between cells and the plasma and/or serum, that undergoes a temporary change in viscosity during centrifugation, the result being that a gel forms and separates the cells and/or clot from the serum/plasma Project: H14
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thoracentesis fluid fluid obtained from removal of pleural fluid from the thoracic cavity Project: H56
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threaded transfer device quick-turn fittings that consist of a plug and a socket that connect with a half turn Project: PRE05
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threshold the level of signal above which a measured value is considered significantly different than background “noise” Project: H42, H43 NOTE: Threshold for instrument fluorescence sensitivity is the level of signal found for what is considered a nonfluorescent object. Threshold for determination of positive antibody staining is the level of signal found for cells not believed to react specifically with a given antibody reagent.
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threshold a glucose concentration above or below which a specific action is indicated Project: POCT13
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threshold an analyte concentration above or below which a specific action is indicated Project: H59 NOTE: In the case of D-dimer, the concentration below which venous thromboembolism can be excluded in the appropriate clinical setting.
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threshold a tolerance limit for performance Project: QMS12
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threshold defined level of signal that separates two populations, eg, the background “noise” Project: H52 NOTE: Threshold for instrument fluorescence sensitivity is the level of signal found for what is a nonfluorescent object. Threshold for determination of positive antibody staining is the level of signal found for cells not believed to react specifically with a given antibody reagent.
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threshold compound a compound for which a concentration has been specified, on either an administrative or scientific basis, above which the compound is deemed to be “positive” or “present” and below which the compound is deemed to be “negative” or “not detected” Project: C43
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thrombin time (thrombin clotting time) based on the principle of the addition of a weak concentration of thrombin (either bovine or human) to citrated plasma Project: H48 NOTE: The time required for the formation of a clot in seconds represents the thrombin time. This coagulation assay is used to diagnose congenital and acquired fibrinogen deficiency as well as to identify contamination by heparin and direct thrombin inhibitors, before performing additional coagulation assays (Ignjatovic V. Thrombin clotting time. Methods Mol Biol. 2013;992:131-138).
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thromboplastin a reagent containing tissue factor and coagulant phospholipids (WHO 880) Project: H54, H47 NOTE 1: Many commercial thromboplastins are crude extracts prepared from mammalian tissues, in which tissue factor is only a minor component on a weight basis, and which also contain phospholipids (WHO 880); NOTE 2: A preparation of a thromboplastin consisting of a tissue extract alone, either with or without added calcium chloride, is termed plain; when the preparation contains adsorbed bovine plasma as a source of additional factor V and fibrinogen, it is termed combined (WHO 880); NOTE 3: Thromboplastins may also be grouped into types, according to the tissue source from which they are derived (eg, human, bovine, rabbit brain or lung, or human placenta) (WHO 880); NOTE 4: The tissue-factor component of recombinant human thromboplastin reagents is produced in Escherichia coli, yeast, or insect cells by recombinant DNA techniques and then lipidated in vitro (WHO 880).
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thromboplastin a phospholipid and/or tissue factor preparation used in the prothrombin time (PT) test that binds Factor VII and VIIa NOTE: The meaning of this term has changed over the years. Originally, it was used to indicate the coagulant activity of a hypothetical lipoprotein found in tissue extracts (Factor III). In current usage, the term is applied to the commercial reagent (which is a crude extract of rabbit or human or other animal brain or lung).
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thromboplastin-specific ISI a thromboplastin international sensitivity index that is generated by the reagent manufacturer specific for the particular thromboplastin/instrument combination Alternate Term: instrument-specific ISI Project: H54, H47
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throughput a term commonly used to describe analytical systems that specify the number of tests that can be performed in a given time Project: POL1/2
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thymus an organ of the immune system, located in the anterior mediastinum where T-cell precursors from bone marrow develop into mature T-cells Project: NBS06 NOTE: T-cell development in the thymus requires both positive and negative selection of cells to create a population of T-cells capable of recognizing self-antigens, while eliminating autoreactive T-cells that may cause autoimmune diseases.
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thyroid hormone binding ratio tests techniques to mathematically adjust total hormone concentrations for binding protein effects Alternate Term: THBR tests Project: C45 NOTE 1: The terminology “thyroid hormone binding ratio” replaces outdated terms such as “T3-uptake” or “T-uptake”; NOTE 2: Thyroid hormone binding ratio tests estimate the concentration of thyroid hormone binding proteins in the serum sample; NOTE 3: According to the Law of Mass Action, a thyroid hormone binding ratio assay should measure the total “thyroid hormone binding capacity,” in which the concentration of all thyroid hormone binding proteins influences the result. In spite of this, some thyroid hormone binding ratio assays are designed to measure primarily the dominant thyroid hormone binding protein, namely thyroxine binding globulin.
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thyrotropin an anterior pituitary gland hormone that stimulates thyroid hormone (ie, thyroxine and triiodothyronine) synthesis and secretion by the thyroid gland Alternate Term: thyroid-stimulating hormone Project: NBS10 Source: Newborn Screening Glossary
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thyroxine an iodine-containing hormone, produced by the thyroid gland as a product of the cleavage of thyroglobulin, that increases metabolic rate and is used to treat thyroid diseases Project: NBS10 Source: Newborn Screening Glossary NOTE 1: Free thyroxine is the biologically active form that is not bound to a binding protein, whereas bound thyroxine attaches to proteins, preventing it from entering body tissues; NOTE 2: Laboratory tests measure total thyroxine (both the free and bound forms) or free thyroxine only, which is generally considered to more accurately reflect biological thyroid hormone status; NOTE 3: 1 µg/dL = 12.87 nmol/L.
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tight glycemic control keeping blood glucose concentrations in a patient as close to “normal” concentrations as possible Project: POCT12
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time above minimal inhibitory concentration the time that the drug concentration exceeds the minimal inhibitory concentration Project: M23
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time in transport the time during which the device is stored or transported to the laboratory once the device is used to collect a clinical specimen. It is defined by the manufacturer to ensure maximum microorganism viability Project: M40
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time of tissue factor-induced coagulation see prothrombin time
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time series a sequence of data points measured at successive times, for which each data point is associated with a specific time
Project: POCT05 NOTE: A time series reflects an underlying process at discrete time intervals. For example, continuous glucose monitoring records time series of the fluctuations in the levels of glucose over time, ie, the underlying process identified by the function G(t).
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timed specimen any specimen collected at specific clock times, or elapsed times, during a clinical diagnostic or therapeutic procedure
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time-in-therapeutic range a quality measure of therapeutic effectiveness for patients on oral anticoagulants Project: H49 NOTE: Depending on the methodology used to measure it, it represents either estimated time (days) spent in a patient-specific therapeutic range or the percent of international normalized ratios in therapeutic range.
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time-kill kinetics the time-dependent reduction in colony-forming units by a fixed concentration of antimicrobial agent Project: VET02 NOTE: This test can be useful to determine whether the agent is bacteriostatic or bactericidal.
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timeliness (of reporting) in terms of critical- and significant-risk results, a habit of reporting results at an opportune time that ensures appropriate medical action to prevent risk or harm to the patient Project: GP47 NOTE: Timeliness can be reported by recording the average number of minutes it takes for results to be communicated, then comparing this to target time frames.
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tincture of iodine an alcoholic solution of iodine and potassium iodide Project: M47 NOTE: Used as a topical agent for disinfecting the skin.
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Tiny Transport Protocol Infrared Data Association transport protocol that provides multiple, concurrent, reliable, bidirectional communication streams on an Infrared Data Association link with robust flow control Project: POCT01
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tissue any coherent collection of animal or plant specialized cells Project: ISO15190 (March 2002)
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tissue microarray an array of cores of tissue arranged in a grid in a block from which sections (slides) can be cut and stained Project: I/LA28 NOTE: The cores of tissue are extracted with a needle or punch. Formalin-fixed, paraffin-embedded tissue or frozen tissue. Core sizes typically range from 0.6 mm to 2.0 mm; however, cores larger than 2.00 mm can be used.
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titer the dilution of the antibody at which a specified percentage of the radiolabeled analyte is bound under defined conditions Project: DI01, LA15
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titer the reciprocal of the dilution factor required to produce a defined outcome in a defined system Project: I/LA23, ILA29, I/LA28 NOTE: The titer is usually proportional to the analyte concentration.
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titer the concentration of a solution as determined by titration; the minimum volume of a solution needed to reach the end point in a titration; the concentration of an antibody as determined by finding the highest dilution at which it is still able to maintain the intended result Project: H62 NOTE: Titer is accurate only for univariate analytical methods when a concentration of a substance is measured.
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titrated heparins typically, an aqueous or dry preparation of heparin salt, prepared with a fixed ratio of calcium to heparin, which minimizes changes to the concentration of ionized calcium, typically at 1.25 mmol/L Project: C31 NOTE: When using these preparations to anticoagulate whole blood, the measured ionized calcium is unchanged, provided the calcium ion concentration of the blood specimen is at or near the concentration of calcium used in the preparation. Mixtures of lithium and zinc heparin are also currently used to limit calcium chelation by heparin.
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titration a method used to determine the infectivity titer of a viral preparation Project: M41 NOTE 1: Serial dilutions (eg, twofold or tenfold) are prepared in diluent (eg, balanced salt solution) and inoculated into replicate (eg, 6 to 8) cell cultures; NOTE 2: The tissue culture infectious dose is the dilution of virus that infects 50% of the monolayers; NOTE 3: The tissue culture infectious dose is considered the endpoint dilution, and the endpoint titer is the inverse of the dilution.
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TN number of true-negative results
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tolerance interval a range that contains a specified proportion of a sampled population with a specified confidence
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tolerance limits specified limits for allowable error. Project: H44 NOTE: Limits should depend on both the effect of the error on the clinical significance of a test and on what is technically achievable.
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top management person or group of people who directs and controls a manufacturer at the highest level (modified from ISO 9000) Project: ISO/DIS 14971
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top of container the open end of the container/test tube closest to the cap Alternate Term: top of tube Project: AUTO01, AUTO07, AUTO02, AUTO12
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top of tube See top of container Project: AUTO01, AUTO02, AUTO12
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total analytical error the interval that contains a specified proportion (usually 90%, 95%, or 99%) of the distribution of differences in concentration between the test and reference method Alternate Term: error Project: GP34 NOTE 1: For example, 97.2% of the differences between the test and reference method fell within the limits of ±4 mmol/L, hence the 95% total analytical error goal was met; NOTE 2: Both “total analytical error” and “error of measurement” contain random and systematic effects.
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total analytical error consists of certain components and is quantified as a confidence interval with confidence level 90% or 95% Project: C56, EP07 NOTE 1: Conceptually the same as “inaccuracy”; NOTE 2: Seeks to estimate the largest likely error (of measurement) as defined by VIM: result of a measurement minus a true value (or accepted reference value); NOTE 3: Estimated from the distribution of differences in concentration between the test and reference measurement procedure; EXAMPLE: 97.2% of the differences between the test and reference measurement procedure fell within the limits of ±4 mmol/L; hence the 95% total analytical error goal was met; NOTE 4: The total analytical error results are usually evaluated against the total allowable error specification.
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total analytical error the interval that contains a specified proportion (usually 95% or 99%) of the distribution of analytical measurement differences between a measurement procedure operating in its stable in-control state and a comparative measurement procedure that is either a definitive reference measurement procedure or one that is traceable to one Project: POCT14, EP21, EP46 EXAMPLE: If 97.2% of the differences between the candidate and comparator measurement procedures fall within the limits of ± 4 mmol/L, the 95% total error goal would be met; NOTE: The term “total analytical difference” is sometimes used to denote cases in which the comparator measurement procedure is not a reference measurement procedure and may contribute significant variability to the total analytical error estimate. In practice, however, “total analytical error” is often used whether or not the comparator measurement procedure is a reference measurement procedure.
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total bacteria all viable aerobic and facultative anaerobic heterotrophic bacteria (in water)
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total calcium the entire calcium concentration in plasma, including ionized calcium and calcium bound to proteins or other molecules such as phosphate, bicarbonate, lactate, and citrate Project: C31
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total carbon total concentration of carbon (organic and inorganic) in a sample Project: GP40
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total carbon dioxide the combination of all of the various forms of carbon dioxide in the plasma in equilibrium with whole blood Alternate Term: Total CO2 Project: GP43 NOTE: Includes CO2 (dissolved), H2CO3, HCO3-, CO3=, protein carbamates, and ion pairs, such as NaHCO3, CaHCO3+, and NaCO3- In blood plasma only two of these species are quantitatively significant: dissolved CO2 and HCO3-.
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total CO2 the combination of all the various forms of carbon dioxide in the plasma in equilibrium with whole blood Project: C46
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total cost the addition of all costs―direct and indirect Project: GP49
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total error the sum of any set of defined errors that can affect the accuracy of an analytical result Project: EP15, EP31 NOTE: EP15 defines total error as the combination of bias and imprecision.
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total error includes all random and systematic errors that can occur during the total testing process, and includes the combined effect of all precision and bias errors that can affect the accuracy of an analytical result NOTE 1: Total error incorporates error sources from the preexamination, examination, and postexamination phases of a measurement procedure; NOTE 2: No CLSI guidelines are available for measuring total error.
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total error the combined impact of any set of defined precision and bias errors that can affect the accuracy of an analytical result Project: EP17 NOTE: Total error can be defined as a combination of bias and imprecision according to a specified error model.
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total error the sum of errors caused by all random and systematic effects that can occur during the total testing process, and includes more errors than would be measured as total analytical error (ie, occurring in the analytical phase alone) Project: EP21, EP46 NOTE 1: Total error incorporates error sources from the preanalytical, analytical, and postanalytical phases of a measurement procedure; NOTE 2: No CLSI guidelines are available for measuring total error.
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total error allowable alternate terminology with the same meaning as "allowable total error"
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total hemoglobin the total of all active and inactive forms (with respect to oxygen-binding capability) of hemoglobin Project: C46, NRSCL08
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total imprecision See and use reproducibility Alternate Term: reproducibility
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total inorganic carbon total concentration of carbon as carbonates, bicarbonates, or dissolved carbon dioxide Project: GP40
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total ion chromatogram chromatogram obtained by plotting the total ion current detected in each of a series of mass spectra recorded as a function of retention time (IUPAC 2006) Project: C43
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total nucleated cell count all nucleated cells, including white cells, nucleated red blood cells, lining cells, and other non-hematopoietic cells Project: H56
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total organic carbon total concentration of carbon in the form of organic compounds Project: GP40
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total precision Note: See and use reproducibility
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total quality management (TQM) a system of managerial programs that includes; 1) team management; 2) plans management, and 3) improvement management NOTE: These programs provide the systematic processes by which CQI can be implemented and maintained.
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total test a concept that the evaluation of the performance of clinical diagnostic testing processes should include assessment of the preanalytical, analytical, and postanalytical phases of the entire testing process Project: I/LA28
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total turnaround time (therapeutic) a time interval that encompasses the entire testing process to obtain an analytical result NOTE: This is the time from when a healthcare provider determines the need for a result to when they have the result to act upon.
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total turnaround time a time interval that encompasses the entire testing process to obtain an analytical result Alternate Term: therapeutic turnaround time Project: AST02, POCT04 NOTE: This is the time from when a health care provider determines the need for a result to when he or she has the result to act upon.
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touch preparation a preparation of cells on a microscope slide, prepared by lightly touching a tissue specimen to the slide Project: NRSCL8, MM04, I/LA28 NOTE: The cells, which are thus transferred, can then be stained after air-drying or fixation.
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toxic concentration concentration of a drug or other substance that is injurious to the patient Project: EP07
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toxic element an element that negatively affects human health Project: C38 NOTE: In some cases, an element that is essential in trace concentrations might become toxic at higher concentrations. In other cases, the presence of an element may have detrimental health consequences.
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toxicity morphologic changes and/or cell lysis occurring in monolayered cell cultures induced by the presence of toxins, pH extremes, metabolites, or other chemical compounds Project: M41
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toxin any poison produced by an organism and characterized by high molecular weight and antigenicity in certain animals
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TP number of true-positive results
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TQM interface the important interchange of information between all three functionally interrelated TQM programs of team management, plans management, and improvement management. This interface ensures synchronization of all three programs
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trace element an element that occurs at a level of 0.01 to 100 µg/g (10 µg/L to 10^4 µg/L) Project: C38
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traceability ability to trace the history, application, or location of that which is under consideration (modified from ISO 9000) Project: QMS01, GP26, I/LA28 Source: Quality Glossary NOTE: When considering a product or a service, traceability can relate to the origin of materials and parts, the processing history, and the distribution and location of the product after delivery (modified from ISO 9000).
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traceability property of the result of a measurement or the value of a standard whereby it can be related to stated references, usually national or international standards, through an unbroken chain of comparisons all having stated uncertainties (ISO 15198) Project: C45, I/LA24, H62
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traceability (metrological) property of the result of a measurement or the value of a standard whereby it can be related to stated references, usually national or international standards, through an unbroken chain of comparisons all having stated uncertainties (ISO 17511, ISO 17593) Project: C37 NOTE 1: The concept is often expressed by the adjective traceable; NOTE 2: The unbroken chain of comparisons is called a traceability chain; NOTE 3: Each comparison is achieved by a (reference) measurement procedure defined in a calibration transfer protocol (ISO 18153); NOTE 4: There are several types of traceability. Therefore the term “metrological traceability” is used in the present text (ISO 18153); NOTE 5: See ISO 17511 and ISO 18153 for examples of traceability chains pertinent to in vitro diagnostic medical devices.
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traceable metrological traceability is a property of a measurement result whereby the result can be related to a reference through a documented unbroken chain of calibrations, each contributing to the measurement uncertainty Project: EP19
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tracer a radiolabeled analyte for use in dose-response for radioimmunoassay Project: I/LA23 NOTE: The production of the tracer may use the replacement of one or more atoms in the analyte with a radioisotope or the covalent labeling of the analyte with an isotope tag, most commonly 125I.
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tracer technique used in process auditing that follows the history, application, or location of an item or activity by means of the associated records Project: QMS17
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tracing technique used in process auditing that follows the history, application, or location of an item or activity by means of the associated records Project: QMS15
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trailing growth reduced but persistent growth over an extended range of concentrations that increases with incubation time Project: M27
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training the education, instruction, or discipline of a person Project: AST03 NOTE: The term "training" is used in this document in a general sense. Training is addressed in the discussion of safety issues and in the discussion of pre- and postanalytical variables.
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training process to provide instruction for performing or improving a job function Project: QMS01, QMS16, QMS03 Source: Quality Glossary
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transcription the process of making RNA from DNA Project: MM02
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transcription mediated amplification (TMA) – an isothermal target nucleic acid amplification method that uses RNA transcription (RNA polymerase) and DNA synthesis (reverse transcriptase) to produce RNA amplicon from a target nucleic acid Project: MM10 NOTE: TMA can be used to target both RNA and DNA.
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transcription the cellular process in which RNA is synthesized from a DNA template Project: MM10, MM12, MM24
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transcription the process of enzymatically synthesizing RNA from a DNA template Project: MM01
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transcriptome 1) the complete expression profile of RNAs of an organism; 2) the full complement of RNAs or transcripts in a particular tissue at a particular time Project: MM09
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transfer the process through which the end-user laboratory implements a reference interval established elsewhere after end user verification Alternate Term: transference Project: EP45
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transfer measurement device device used as an intermediary to compare measurement standards (JCGM 200:2012) Alternate Term: transfer device Project: ISO IEC Guide 99 NOTE: Sometimes, measurement standards are used as transfer devices (JCGM 200:2012).
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transfer protocol see calibration transfer protocol
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transfer standard standard used as an intermediary to compare standards NOTE
The term transfer device should be used when the intermediary is not a standard.
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transferrin saturation the mass concentration of serum and/or plasma iron expressed as a fraction of total iron (mass concentration) binding capacity (TIBC); S Fe (%) = cFe (P) • 100 • TIBC -1. See also Fraction, Saturate Project: H17
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transferrin saturation measured as a percentage, refers to the ratio of serum iron and total iron-binding capacity, multiplied by 100 NOTE: Transferrin saturation is usually reported with total iron binding capacity, which measures the blood’s capacity to bind iron with transferrin.
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transformation zone the region of immature and mature metaplastic epithelium that lies between the original (anatomic) squamocolumnar junction and columnar epithelium of the cervix; it is the site where the vast majority of epithelial precancerous and cancerous lesions occur Project: GP15
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transformed value (of a measurand) value of measurement signal representing a given measurand
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transfusion the transfer of whole blood or blood products from one individual to another Project: NBS03
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transient congenital hypothyroidism a temporary condition in which thyroid hormone levels are low at birth but return to in range over the first months to years of life Project: NBS10 Source: Newborn Screening Glossary NOTE: “Transient” is sometimes used to refer to screen-positive results in newborns without confirmed congenital hypothyroidism, but that definition does not apply in NBS10.
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transition a defined precursor ion m/z and accompanying product ion m/z Project: C64
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transition mutation substitution of one purine base for another purine base, or one pyrimidine base for another pyrimidine base
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transitory record routine or other documents that have short-term value and are (1) not an integral part of an administrative or operational records, (2) not required to sustain administrative or operational functions, (3) not regularly filed under a standard records classification, (4) not required to meet statutory obligations, and (5) recorded only for the time required for completion of actions or ongoing records with them Project: QMS26
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translocation the fusion of two distinct DNA sequences located on different chromosomes or different parts of a single chromosome Project: MM05
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transmission See transmittance
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Transmission Control Protocol an Internet Standard protocol that reliably delivers a sequence of datagrams (discrete sets of bits) from one computer to another in a computer network (RFC 2828) Project: AUTO09
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Transmission Control Protocol a transport protocol that provides reliable, bidirectional, stream-oriented network communication Alternate Term: Internet Protocol Project: POCT01 NOTE: Transmission Control Protocol/Internet Protocol is one of the foundation protocols of the Internet.
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transmittance the ratio of radiant power transmitted by a sample to the radiant power incident on the sample Alternate Term: transmission Project: H15 NOTE: Transmittance is usually expressed as percent transmittance. An alternative term is “transmission.”
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transparency ability of a measuring instrument not to alter the measurand; EXAMPLES: a) a mass balance is transparent; b) a resistance thermometer that heats the medium whose temperature it is intended to measure is not transparent
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transport the act of moving a sample from one point to another Project: M40 NOTE 1: Usually from collection to testing site; NOTE 2: Transport may include intramural (eg, pneumatic tube system) and extramural (car, plane, bus) components; NOTE 3: Any container that is used for transporting a microbiology sample shall fall under the standards outlined in M40.
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transport and storage temperature the prevailing temperature within trucks, shipping containers, or interim storage facilities such as warehouses, which should be within the limits defined by the manufacturer and posted on the device label or packaging Project: M40 NOTE: This includes storage within the laboratory or central supply area before distribution to clinicians for use, as well as following receipt in the laboratory.
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transport conditions environmental conditions (eg, temperature, humidity, light exposure) that a product will be exposed to during the distribution period from manufacture until customer receipt Project: EP25
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transport container may be a transparent container accommodating the transport medium and the specimen containing microorganism and, in some cases, the sampling device Project: M40
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transport media nutrient-rich media used to stabilize cells in a patient specimen for a sufficient period of time to allow transport to the laboratory and storage until analysis can be performed Project: H43 NOTE: Roswell Park Memorial Institute with fetal calf serum is an example.
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transport medium liquid or semisolid medium designed to preserve and maintain the integrity of the specimen for the time period between specimen collection and laboratory processing of the sample Project: M40
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transport stability testing exposure of the product to conditions designed to simulate the extremes of environmental factors (worst-case testing) that might occur during the distribution process from manufacture to end-user storage Alternate Term: transport simulation Project: EP25, EP30
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transport swab transport swab, which may be supplied as part of the transport system, comprises a swab applicator stick(s) covered at one end with a material such as spun rayon or polyester fibers, foam (such as polyurethane), or flocked fibers Project: M40 NOTE: A transport swab may or may not have a stated claim for the maintenance of viable microorganisms, or for the preservation of antigenic or molecular components of a microorganism(s) either by itself or when used as a component of a transport system.
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transport system for the purposes of this document, a transport system is a device that ensures the integrity of a specimen and provides for safe handling during the interval between specimen collection and processing of a specimen in a laboratory and should include any wait time before culturing in the actual laboratory Project: M40 NOTE 1: The transport system may include a transport swab; NOTE 2: The transport system includes a transport container, which may or may not contain a liquid or semisolid (formulation) transport medium; NOTE 3: Manufacturers may specify that, for certain transport devices, such as flocked or foam swabs, the swab may be discarded after the specimen on the swab has been transferred to the transport medium using a method (eg, vortexing) specified by the manufacturer; NOTE 4: It does not include packaging materials that conform to various regulations pertaining to the transport of etiological agents.
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transudate as a subtype of pleural fluid, due to changes in hemodynamic pressures, typically paucicellular and low in protein; often seen in congestive heart failure
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transudate the accumulation in a body cavity of a fluid having a low concentration of protein
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transudates fluid with a low concentration of protein that has accumulated in a body cavity Project: H56
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transversion mutation substitution of a purine base for a pyrimidine base or vice versa
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trapped plasma the amount of plasma that, upon centrifugation, remains below the apparent red cell-plasma interface Project: H07 NOTES: a) It may be localized in the upper portion of the red cell column, or distributed more or less uniformly throughout the packed red cells; b) The amount of plasma trapped is often expressed as a percentage (fraction × 100) of the red cell column; c) The amount of plasma trapped is slight in macrocytic anemias and is considerable in sickle cell anemia, in spherocytosis, and in the thalassemias.
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traumatic tap contamination of body fluids by extraneous cells or fluid derived from blood or tissue during the procedure of withdrawal of fluid from a body cavity Project: H56
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travelling measurement standard measurement standard, sometimes of special construction, intended for transport between different locations (JCGM 200:2012) Alternate Term: travelling standard Project: ISO IEC Guide 99 EXAMPLE: Portable battery-operated caesium-133 frequency measurement standard (JCGM 200:2012).
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travelling standard standard, sometimes of special construction, intended for transport between different locations; EXAMPLE: a portable battery-operated caesium frequency standard
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tray a holder for one or more carriers (optional) Project: AUTO01, AUTO07, AUTO02
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treatment process by which wastes are made less hazardous, nonhazardous, nontoxic, or noninfectious, or are converted to another physical form (eg, stabilized or encapsulated) Project: GP05
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treatment administration of an antimicrobial agent to an animal, or group of animals that exhibits frank clinical disease Project: VET06
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treatment the administration of an antimicrobial agent as a remedy for an individual animal with evidence of infectious disease Project: VET03, VET01, VET09 NOTE 1: On a population basis, the administration of an antimicrobial agent to those animals within the group with evidence of infectious disease; NOTE 2: Therapeutic use of antimicrobial drugs includes treatment, control (also known as metaphylaxis), and prevention (also known as prophylaxis); NOTE 3: See breakpoint, control, and prevention//prophylaxis.
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trend 1) an upward or downward tendency, after exclusion of the random error and cyclic effects, when observed values are plotted in the order of observations (ISO3534-1/93-2.47); 2) in plots of daily quality control points, a gradual change in a particular direction of those values over a period of time Project: ISO3534-1/93-2.47, POCT04
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trend direction of movement; prevailing tendency or inclination Project: POCT05 NOTE: In statistics, a trend is a long-term movement in time series data, also defined as very low-frequency variation with wavelengths, which are greater than the length of the time series.
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trend (database) an upward or downward tendency, after exclusion of the random error and cyclic effects, when observed values are plotted in the order of observations (ISO 3534-2) Project: POCT05
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trend accuracy the ability of a continuous glucose monitoring system to correctly measure the rate and direction of changes in glucose concentration over time Project: POCT05
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triiodothyronine a biologically active metabolite of thyroxine formed by removal of an iodine atom in the outer ring of thyroxine Alternate Term: 3, 5, 3′-triiodothyronine Project: NBS10 Source: Newborn Screening Glossary NOTE: 1 ng/dL = 10 ng/L = 0.0154 nmol/L.
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trinucleotide (triplet) repeat disorders disorders caused when the number of repeating units of a trinucleotide in a particular gene expands beyond a threshold and interferes with gene expression or function
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triplet state excited state of a molecule in which the electrons in the higher-energy and lower-energy orbitals have the same spin Project: I/LA24 NOTE 1: Transitions to and from triplet states, which require changes of spin, have a low probability of occurrence; NOTE 2: Phosphorescence is the emission resulting from transition from a triplet state to a ground state.
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trophozoite the feeding, motile stage of protozoa Project: M28
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troubleshooting series of tasks designed to systematically investigate, identify, and correct the malfunctioning instrument/equipment Project: QMS13 NOTE: All necessary adjustments made to correct the problem need documenting.
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true alert rate the percentage of occasions in which the continuous glucose monitor alerted when the reference blood glucose level reached the alert setting within a prespecified time window (typically 15–30 minutes) before or after the device alerted Project: POCT05
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true negative a negative result of a test for a disease or condition in a subject in whom the disease or condition is absent Alternate Term: true-negative result Project: H20
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true positive an observation for which an event alert is accompanied by the relevant hypoglycemic or hyperglycemic event Project: POCT05 NOTE: The glucose level that determines the event must be determined by a well-accepted method independent of the device under investigation.
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true positive a positive test result for a disease or condition when the disease or condition is present Project: H20, M47 NOTE: For blood cultures, a culture that yields a microbial isolate(s) that is determined to be the cause of bloodstream infection.
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true quantity value quantity value consistent with the definition of a quantity (JCGM 200:2012) Alternate Term: true value of a quantity; true value Project: ISO IEC Guide 99, C51, C24 NOTE 1: In the Error Approach to describing measurement, a true quantity value is considered unique and, in practice, unknowable. The Uncertainty Approach is to recognize that, owing to the inherently incomplete amount of detail in the definition of a quantity, there is not a single true quantity value but rather a set of true quantity values consistent with the definition. However, this set of values is, in principle and in practice, unknowable. Other approaches dispense altogether with the concept of true quantity value and rely on the concept of metrological compatibility of measurement results for assessing their validity (JCGM 200:2012); NOTE 2: In the special case of a fundamental constant, the quantity is considered to have a single true quantity value (JCGM 200:2012); NOTE 3: When the definitional uncertainty associated with the measurand is considered to be negligible compared to the other components of the measurement uncertainty, the measurand may be considered to have an “essentially unique” true quantity value. This is the approach taken by the GUM and associated documents, where the word “true” is considered to be redundant (JCGM 200:2012); NOTE 4: For most measurands, there is no single true quantity value but rather a set of true quantity values consistent with the definition; they are expressed as a definitional uncertainty associated with a measured quantity value. If the definitional uncertainty is considered to be negligible compared to the other components of a measurement uncertainty, the measurand may be considered to have an “essentially unique” true quantity value; NOTE 5: There are multiple approaches to considering the true value.
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true value the value consistent with the definition of a given particular quantity (VIM93-1.19) NOTES: a) A value that would be obtained by a perfect measurement; b) True values are by nature indeterminant. (VIM93-1.19)
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true value (of a quantity) value consistent with the definition of a given particular quantity NOTES: 1) This is a value that would be obtained by a perfect measurement; 2) True values are by nature indeterminate; 3) The indefinite article "a", rather than the definite article "the", is used in conjunction with "true value" because there may be many values consistent with the definition of a given particular quantity.
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true value See true quantity value Alternate Term: true quantity value; true value of a quantity Project: C51
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true value of a quantity value consistent with the definition of a given particular quantity (VIM:1993,1.19) Alternate Term: true value Project: ISO 17511, ISO 15195 (March 2002) NOTE 1: This is a value that would be obtained by a perfect measurement (VIM:1993,1.19); NOTE 2: True values are by nature indeterminate (VIM:1993,1.19); NOTE 3: The indefinite article “a,” rather than the definite article “the,” is used in conjunction with “true value” because there may be many values consistent with the definition of a given particular quantity (VIM:1993,1.19); NOTE 4: The “definition of a given particular quantity” may have to include the measurement procedure applied. Therefore, a true value may depend on a specified measurement procedure; NOTE 5: ISO 3534-1:1993, instead of “a true value,” uses the concept “the accepted reference value,” which can be a theoretical (true), assigned, consensus, or procedure-defined value.
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true value of a quantity See true quantity value Alternate Term: true quantity value; true value Project: C51
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true-negative fraction See specificity Project: EP24
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true-negative ratio (TNR) the ratio of subjects who do not have a disease or condition, and whose tests are negative, to all subjects who do not have the disease; TN/(TN + FP) Project: NRSCL8 NOTE: See also Specificity and Ratio.
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true-negative result a negative result for a subject in whom the condition of interest is absent (as determined by the diagnostic accuracy criteria) Project: EP33 NOTE: In the context of EP33, a true-negative result indicates that a delta check alert did not occur when there was no change of interest to the laboratory.
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true-negative result a negative test result for a patient or specimen that is negative for the condition or constituent being investigated Alternate Term: true negative Project: MM17, MM09
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true-negative result negative test result in a subject in whom the disease is absent Project: EP24
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true-negative screening result screen-negative result in an unaffected newborn Source: Newborn Screening Glossary
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trueness (of measurement) closeness of agreement between the average of an infinite number of replicate measured quantity values and a reference quantity value (JCGM 200:2012) Alternate Term: trueness of measurement; measurement trueness Project: JCGM 200:2012, GP16, EP18, C43, H26, MM06, I/LA28, GP34, H02, EP23, EP10, C51, MM01, EP27, MM14, EP09, EP06, EP15, MM03, POCT06, EP19, MM21, H48, EP21, C64, QMS24, EP34, EP07, EP30, MM24, POCT16 NOTE 1: Measurement trueness is not a quantity and thus cannot be expressed numerically, but measures for closeness of agreement are available (JCGM 200:2012); NOTE 2: Measurement trueness is inversely related to systematic measurement error but is not related to random measurement error (JCGM 200:2012); NOTE 3: “Measurement accuracy” should not be used for “measurement trueness” and vice versa (modified from JCGM 200:2012); NOTE 4: In the case of total serum immunoglobulin E assays, the WHO IgE Standard 75/502, (1 IU = 2.42 ng) and the United States IgE Standard have been used as primary reference material to promote trueness. For immunoglobulin E antibody assays of defined allergen specificity, there are currently no universally accepted immunoglobulin E antibody standards with calibrated levels of allergen-specific immunoglobulin E. Heterologous interpolation of allergen-specific immunoglobulin E antibody results from a total immunoglobulin E dose response curve has become a universally accepted calibration method. Over the years, several research-based secondary immunoglobulin E antibody standards have been prepared with mass per volume unit estimates using antibody adsorption or depletion methods; NOTE 5: Trueness is usually expressed numerically by the statistical measure “bias,” which is inversely related to trueness; NOTE 6: The measure of trueness is usually expressed in terms of bias (ISO 17511, ISO 3534-2); NOTE 7: Closeness of agreement between the average value obtained from a large series of results of measurements and a true value (modified from ISO 17511); NOTE 8: See accuracy and bias.
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trueness (of measurement) closeness of agreement between the average value obtained from a large series of results of measurements and a true value (modified from ISO 17511) Project: ISO 15195 (March 2002), ISO 15189, ISO 17511, C45, C48, H49, C52, I/LA21, C57, C50, EP28, POCT14 NOTE 1: “Trueness of measurement” is a qualitative concept (ISO 15195); NOTE 2: The difference between the average value from a large series of measurements and the true is also called “bias” or systematic error; NOTE 3: Trueness is usually expressed numerically by the statistical measure bias that is inversely related to trueness; NOTE 4: Trueness of measurement cannot be given a numerical value in terms of the measurand, only ordinal values (eg, sufficient, insufficient); NOTE 5: The degree of trueness is usually expressed numerically by the statistical measure bias that is inversely related to trueness and is the difference between the expectation of the results of measurement and a true value of the measurand; NOTE 6: Trueness of measurement cannot be given a numerical value in terms of the measurand, only ordinal values (eg, sufficient, insufficient); NOTE 7: The degree of trueness is usually expressed numerically by the statistical measure bias that is inversely related to trueness and is the difference between the expectation of the results of measurement and a true value of the measurand.
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trueness closeness of agreement between the average value obtained from a large series of test results and an accepted reference value (modified from ISO 5725-1) Project: ISO 15197, M51, C33, C37, EP14, EP17, I/LA23, I/LA25, H54, GP20, MM10, ISO 15198, MM12, H20, ISO 17593, H26, C58, MM20, C40, H60, POCT13, EP31 NOTE 1: The measure of trueness is usually expressed in terms of bias (ISO 5725-1); NOTE 2: Trueness has been referred to as “accuracy of the mean.” This usage is not recommended (ISO 5725-1); NOTE 3: Trueness is usually expressed numerically by the statistical measure bias that is inversely related to trueness; NOTE 4: A measure of trueness is usually expressed as bias (ISO 17593); NOTE 5: See accuracy and bias.
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trueness the closeness of agreement between the expectation of a test result or a measurement result and a true value (ISO 3534-2) Project: POCT05, C62 NOTE 1: Trueness is usually expressed numerically by the statistical measure bias that is inversely related to trueness. See also accuracy and bias; NOTE 2: The measure of trueness is usually expressed in terms of bias (ISO 3534-2).
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trueness closeness of agreement between the average value obtained from an infinited series of test results and an accepted reference value Project: EP32 NOTE 1: The measure of trueness is usually expressed in terms of bias; NOTE 2: Trueness has been referred to as “accuracy of the mean.” This usage is not recommended.
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trueness control reference material that is used to assess the measurement bias of a specified quantity in a specified measuring system (ISO 17511) Project: EP32, EP30 NOTE 1: Trueness control materials are often prepared in a matrix designed to emulate the matrix of the intended human samples (ISO 17511); NOTE 2: Trueness control materials should be evaluated to establish their commutability with human samples (ISO 17511); NOTE 3: Trueness control materials may be made available by their manufacturers as certified reference materials (ISO 17511).
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trueness control material reference material that is used to assess the bias of measurement of a measuring system (ISO 17511) Project: ISO 17511, ISO 18113-1
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trueness control material a reference material with measurand value assigned by a procedure traceable to a higher-order reference system and with commutability properties suitable for use to assess bias of measurement of a specified measurement procedure (modified from ISO 17511) Project: EP23
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true-positive fraction See sensitivity Project: EP24
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true-positive ratio (TPR) The ratio of subjects who have the disease or condition, and whose test results are positive, to all subjects who have the disease; TP/(TP + FN). See also Sensitivity, Ratio
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true-positive result a positive result for a subject in whom the condition of interest is present (as determined by the diagnostic accuracy criteria) Project: EP33 NOTE: In the context of EP33, a true-positive result refers to a delta check alert that does identify the type of change of interest to the laboratory.
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true-positive result a positive test result for a patient or specimen that is positive for the condition or constituent being investigated Alternate Term: true positive Project: MM17, MM09
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true-positive result positive test result in a diseased or affected subject Project: EP24
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true-positive screening result screen-positive result in an affected newborn Source: Newborn Screening Glossary
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trunked communications system a computer-controlled radio system which provides highly reliable, flexible, and often secure voice communications options to large numbers of governmental and public service users NOTE: Such systems are current state of the art for local, regional, or state law enforcement, fire, and medical emergency communications.
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truth table (2x2) a type of mathematical table used in logic to determine whether an expression is true or whether an argument is valid or whether test results from different methods are comparable NOTE 1: The rows show each possible combination of inputs, one combination per row, and the outputs that result from each combination of inputs; NOTE 2: For comparing two different methods (A and B), the four possible entries in a 2x2 truth table are: Concordant results—A and B both positive, A and B both negative; Discordant results—A positive and B negative, A negative and B positive.
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t-test an abbreviation for the Student’s t-test, a statistical test based on the Student’s t-distribution Project: EP10 NOTE: The Student’s t-test can be applied to dependent and independent variables with equal or unequal variances. Although a robust statistic, a gaussian distribution of the data is assumed.
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tube See specimen collection container Project: AUTO01, AUTO02, AUTO03, AUTO12
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tube rigid part of the assembly that contains the specimen Project: GP39
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tube closure component that allows needle penetration into the container and that can be removed or pierced to obtain an aliquot of the specimen Project: GP39 NOTE: A tube closure is often referred to as a stopper.
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tube coating material applied to the interior surface of the tube Project: GP39
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tube interior inside surfaces of the tube and closure that come into contact with the blood specimen Project: GP39
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tumor necrosis factor alpha a proinflammatory cytokine produced by a number of cells, including activated T-cells Project: I/LA26
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tumor suppressor gene a gene that codes for a protein that can function to restrict progression through the cell cycle or promote cell death to regulate tumorigenesis Project: MM23
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turbidity the condition that exists when a liquid sample contains insoluble matter of sufficient particle size to cause part of the incident light upon the sample to be scattered Project: H15, VET04, VET03 NOTE 1: Turbidity causes erroneously high absorption measurements; the magnitude of the error depends on the optical geometry of the measuring instrument; NOTE 2: Units of measurement include, but are not limited to, McFarland units (0.5 = 80-88% transmittance, 1.0 = 67-77% transmittance, 2.0 = 46-56% transmittance, and 3.0 = 27-37% transmittance): nephelometric turbidity units with a range of 0 to 10 000 nephelometric turbidity units, or spectrophotometric units at a set wavelength.
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turbidity a condition in which lipid levels in the blood are sufficiently elevated to cause the sample to appear milky or turbid Project: C56
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turnaround time time interval that encompasses a process to determine availability of a defined outcome Project: QMS05, MM26 NOTE: Turnaround time can be calculated from multiple time points, such as the time from when a health care provider determines the need for a result to when he or she has the result to act on; the time the sample is received in the laboratory to when the result is available to the health care provider; or the time from when the sample is submitted to the referral laboratory until results are returned to the referring laboratory.
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turnkey a computer system that has been customized for a particular application Project: POCT02 NOTE 1: The term derives from the idea that the end user can just turn a key and the system is ready to go; NOTE 2: Turnkey systems include all the hardware and software necessary for the particular application.
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turnover number the number of substrate molecules converted by an enzyme to product molecules per unit time when the enzyme is saturated with substrate (under optimum conditions) Project: I/LA23, ILA29
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two-sided test statistical test of significance that is used when the alternative hypothesis does not state the direction (positive or negative) of the interference effect, such as a ±0.2 mg/dL difference at a creatinine concentration of 1.0 mg/dL Project: EP07
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two-site immunometric assay See sandwich immunoassay Project: H59
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two-tailed test the test of a given statistical hypothesis in which a value of the statistic that is either sufficiently small or sufficiently large will lead to rejection of the hypothesis tested Project: ILA29
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Type A evaluation See Type A evaluation of measurement uncertainty Alternate Term: Type A evaluation of measurement uncertainty Project: C51
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Type A evaluation of measurement uncertainty evaluation of a component of measurement uncertainty by a statistical analysis of measured quantity values obtained under defined measurement conditions (JCGM 200:2008) Alternate Term: Type A evaluation Project: ISO IEC Guide 99, C51 NOTE 1: For various types of measurement conditions, see repeatability condition of measurement, intermediate precision condition of measurement, andreproducibility condition of measurement (JCGM 200:2012); NOTE 2: For information about statistical analysis, see eg, ISO/IEC Guide 98-3 (JCGM 200:2012); NOTE 3: See also ISO/IEC Guide 98-3:2008, 2.3.2, ISO 5725, ISO 13528, ISO/TS 21748, ISO 21749 (JCGM 200:2012); NOTE 4: Although Type A and Type B evaluations are treated the same mathematically, in applications for clearance or approval of devices by regulatory agencies, Type A evaluations are generally preferred when they are practical.
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Type B evaluation See Type B evaluation of measurement uncertainty Alternate Term: Type B evaluation of measurement uncertainty Project: C51
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Type B evaluation of measurement uncertainty evaluation of a component of measurement uncertainty determined by means other than a Type A evaluation of measurement uncertainty (JCGM 200:2008) Alternate Term: Type B evaluation Project: ISO IEC Guide 99, C51 EXAMPLES: Evaluation based on information:
— associated with authoritative published quantity values,
— associated with the quantity value of a certified reference material,
— obtained from a calibration certificate,
— about drift,
— obtained from the accuracy class of a verified measuring instrument,
— obtained from limits deduced through personal experience (JCGM 200:2012).
NOTE 1: See also ISO/IEC Guide 98-3:2008, 2.3.3; NOTE 2: Although Type A and Type B evaluations are treated the same mathematically, in applications for clearance or approval of devices by regulatory agencies, Type A evaluations are generally preferred when they are practical.
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type I error an incorrect judgment or conclusion that occurs when an association is found between variables where, in fact, no association exists Project: GP45, EP31 EXAMPLE: If the experimental procedure does not have an effect, chance or random error may cause the researcher to conclude that the experimental procedure did have an effect; NOTE: Also known as “false positive” or “alpha error.”
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type I error falsely rejecting the null hypothesis when it is true Alternate Term: alpha error, false positive Project: EP12
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type I error probability of rejecting the null hypothesis when it is true Project: EP14
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type I error (alpha) probability of falsely rejecting the null hypothesis that a substance is not present when it is true, ie, a false-positive result Project: EP17
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type I hypersensitivity an allergic reaction provoked by re-exposure through ingestion, inhalation, injection, or direct contact to a specific type of antigen referred to as an allergen. It involves immunoglobulin E antibodies that bind to Fc receptors on the surface of tissue mast cells and blood basophils. Mast cells and basophils coated by immunoglobulin E are “sensitized.” Later exposure to the same allergen crosslinks the bound immunoglobulin E on sensitized cells resulting in degranulation and the secretion of pharmacologically active mediators such as histamine, leukotriene (LTC4 and LTD4), and prostaglandin that act on the surrounding tissues. The principal effects of these products are vasodilation and smooth-muscle contraction Project: I/LA34
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type II error an incorrect judgment or conclusion that occurs when no association is found between variables where, in fact, an association does exist Project: GP45, EP31 EXAMPLE: In a medical screening, a negative test result may occur by chance in a subject who possesses the attribute for which the test is conducted; NOTE: Also known as “false negative” or “beta error.”
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type II error falsely accepting the null hypothesis when it is false Project: EP12
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type II error (beta) probability of falsely accepting the null hypothesis that a substance is absent, when in fact the substance is present at the designated level, ie, a false-negative result Project: EP17
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type II error probability of failing to reject the null hypothesis when it is false Project: EP14
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type size the size of the font employed, such as 8, 10, 11, 12, and so on Project: AUTO12 NOTE: A size 10 in one font may be as large as a size 12 in another font.
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type strain populations of cells arising from a single cell that are used as the reference phenotype for a given taxon Project: M64
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type test test of one or more samples of equipment (or parts of equipment) made to a particular design, to show that the design and construction meet one or more requirements of the applicable standard (ISO 17593) Project: ISO 17593 NOTE: Statistical sampling is not required for a type test (ISO 17593).
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typeability in bacterial strain typing, the ability of a typing system to give a definite result for a given isolate (ie, to assign a type to the isolate) Project: MM11, MM24
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typeface in typography, a set of one or more fonts, in one or more sizes, designed with stylistic unity, each comprising a coordinated set of glyphs. A typeface usually comprises an alphabet of letters, numerals, and punctuation marks; it may also include ideograms and symbols, or consist entirely of them (for example, mathematical or mapmaking symbols) Project: AUTO12 NOTE 1: The term typeface is frequently conflated with font; the two terms had more clearly differentiated meanings before the advent of desktop publishing. The distinction between font and typeface is that a font designates a specific member of a type family such as roman, boldface, or italic type, whereas typeface designates a consistent visual appearance or style that can be a “family” or related set of fonts. For example, a given typeface such as Arial may include roman, bold, and italic fonts. In the metal type era, a font also meant a specific point size, but with digital scalable outline fonts; this distinction is no longer valid because a single font may be scaled to any size. (For the purposes of AUTO12, typeface as a descriptor is used to specify the sans serif classes of typefaces, which are specifically selected over serif typefaces, owing to a significant body of psychometric evidence that they have better legibility at small font sizes); NOTE 2: A type font, such as Times New Roman, Courier, Arial, and so on. The first two are examples of serif fonts, whereas the latter is an example of a sans serif font.
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ultrafiltration a process in which colloidal suspensions (sols) are purified by forcing them under pressure through filters (semipermeable membranes) of sufficiently small pore size to cause retention based on particle size of suspended impurities
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ultratrace element arbitrarily defined as an element that occurs at a level < 0.01 µg/g (< 10 µg/L) Project: C38 NOTE: From the perspective of preventing preexamination or examination contamination, issues impacting trace-level testing are more impactful to ultratrace-level testing. Classification of an element as trace or ultratrace depends on (1) the expected concentration in the sample matrix and (2) the sensitivity of the analytical method used for that element in a specific matrix. Thus, for example, while aluminum occurs in the serum of healthy persons as an ultratrace element, in a patient on dialysis who has aluminum toxicity, aluminum may be considered a trace element.
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unacceptable antigens (UA) human leukocyte antigens to which a potential recipient has developed antibodies Project: ILA29 NOTE: The unacceptable antigens must be avoided when choosing a potential donor.
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unaltered biological matrix milieu in which the analyte exists that has not been modified or changed from the normal specimen collection process Project: EP39 EXAMPLES: Serum; plasma; urine; cerebrospinal fluid; swabs stored in collection media; formalin-fixed, paraffin-embedded tissue.
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unassayed control material control material that has no assigned analyte values provided by the manufacturer Project: EP23
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unbalanced See balanced Project: EP05
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uncentrifuged specimen a blood specimen that was not centrifuged
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uncertainty (of measurement) non-negative parameter characterizing the dispersion of the quantity values being attributed to a measurand, based on the information used (JCGM 200:2012) Alternate Term: uncertainty of measurement; measurement uncertainty Project: GP26, QMS21, POCT05, POCT05, C43, POCT07, MM06, GP34, EP21, EP24, C51, MM20, C40, H60, C62, EP05, C57, EP19, QMS24, C24, EP34, MM17, EP46, QMS01 Source: Quality Glossary NOTE 1: Measurement uncertainty includes components arising from systematic effects, such as components associated with corrections and the assigned quantity values of measurement standards, as well as the definitional uncertainty. Sometimes estimated systematic effects are not corrected for but, instead, associated measurement uncertainty components are incorporated (JCGM 200:2012); NOTE 2: The parameter may be, for example, a standard deviation called standard measurement uncertainty (or a specified multiple of it), or the half-width of an interval, having a stated coverage probability (JCGM 200:2012); NOTE 3: Measurement uncertainty comprises, in general, many components. Some of these may be evaluated by type A evaluation of measurement uncertainty from the statistical distribution of the quantity values from series of measurements and can be characterized by standard deviations. The other components, which may be evaluated by type B evaluation of measurement uncertainty, also can be characterized by standard deviations, evaluated from probability density functions based on experience or other information (JCGM 200:2012); NOTE 4: In general, for a given set of information, it is understood that the measurement uncertainty is associated with a stated quantity value attributed to the measurand. A modification of this value results in a modification of the associated uncertainty (JCGM 200:2012); NOTE 5: The parameter may be, eg, a standard deviation (or a given multiple of it), or the half-width of an interval, having a stated level of confidence (modified from ISO 15195).
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uncertainty (of measurement) parameter, associated with the result of a measurement, that characterizes the dispersion of the values that could reasonably be attributed to the measurand (ISO 15195) Project: ISO 15189, ISO 15195, ISO 17511, I/LA24 NOTE 1: The parameter may be, for example, a standard deviation (or a given multiple of it), or the half-width of an interval having a stated level of confidence (ISO 15195); NOTE 2: “Uncertainty of measurement” comprises, in general, many components. Some of these components may be evaluated from the statistical distribution of the results of series of measurements and can be characterized by “experimental standard deviations.” The other components, which can also be characterized by standard deviations, are evaluated from assumed probability distributions based on experience or other information (ISO 15195); NOTE 3: It is understood that the result of the measurement is the best estimate of the value of the measurand, and that all components of uncertainty, including those arising from systematic effects, such as components associated with corrections and reference standards, contribute to the dispersion (ISO 15195); NOTE 4: The components of uncertainty are evaluated experimentally from statistical distributions (Type A) or evaluated from assumed probability distributions based on experience or other information (Type B). All components are expressed as standard uncertainties that are combined into one final expression (ISO 17511).
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uncertainty an estimate attached to a test result which characterizes the range of values within which the true value is asserted to lie (ISO 3534-1) Project: C43
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uncertainty budget statement of a measurement uncertainty, of the components of that measurement uncertainty, and of their calculation and combination (JCGM 200:2008) Project: ISO IEC Guide 99, C51 NOTE: An uncertainty budget should include the measurement model, estimates, and measurement uncertainties associated with the quantities in the measurement model, covariances, type of applied probability density functions, degrees of freedom, type of evaluation of measurement uncertainty, and any coverage factor (JCGM 200:2012).
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uncertainty of measurement parameter, associated with the result of a measurement, that characterizes the dispersion of the values that could reasonably be attributed to the measurand
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uncertified value a value of a quantity, included in the certificate of a CRM or otherwise supplied, which is provided for information only but is not certified by the producer or the certifying body (ISO Guide 30/92- 3.2)
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unclaimed microorganisms species that have been validated by the manufacturer, but are not yet approved/cleared for reporting by a regulatory organization Project: M58
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unconditional safety those aspects of the design and manufacture of a medical device that render it intrinsically safe and not dependent on the user or installer for its effectiveness (ISO Guide 63-2.13) Project: ISO Guide 63-2.13
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uncontrolled copy copy of an approved document for use within a specified time period, or for a special use (eg, approved distribution outside the facility to a regulatory or accreditation organization) and that is marked in a manner (eg, not controlled) to indicate that the copy will not be accounted for when making revisions or retiring the document Project: QMS02
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uncorrected result result of a measurement before correction for systematic error
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unexpected antibody antibody that is not an isoagglutinin or a naturally occurring antibody Project: I/LA33
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Unicode a fixed-width, 16-bit worldwide character encoding system that was developed and is maintained by the Unicode Consortium, supporting all national languages Project: AUTO01, AUTO02, AUTO03, AUTO14 NOTE 1: The Unicode Consortium is a nonprofit computer industry organization NOTE 2: The Unicode standard provides the basis for processing, storage, and interchange of text data in any language in all modern software and information technology protocols. Unicode has developed several worldwide character encoding systems that differ in how many bytes are required to represent a character in memory; NOTE 3: See UTF-8.
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Unicode Transformation Format-8 Bit (UTF-8) multibyte encoding for text that represents each Unicode character with 1 to 4 bytes, and which is backward-compatible with American Standard Code for Information Interchange (ASCII) Alternate Term: UTF-8 Project: AUTO14 NOTE: UTF-8 is the predominant form of Unicode in web pages
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unidentify a process where all information about the patient would be removed and replaced with a character such as “*” Project: AUTO09 NOTE: This would be substituted for any patient-identifiable information. It would not be possible to cross-reference these data back to a patient, if they were needed to fully document an event or problem.
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unidirectional interface involves the transfer of information in one direction only, from the laboratory information system or Blood Establishment Computer Software to the automated system or from the automated system to the laboratory information system or Blood Establishment Computer Software Project: I/LA33 NOTE: See also bidirectional interface.
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unidirectional workflow the manner in which testing personnel and patient specimens move through the molecular amplification process to minimize cross-contamination and backflow of amplified nucleic acid from previous reactions Project: MM19, MM22, MM24
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unified atomic mass unit (u) 1/12th the atomic mass of 12C (carbon-12) Project: C50 NOTE 1: The term atomic mass unit is obsolete; NOTE 2: Although there is currently no SI term/symbol for Dalton, currently, both the terms/symbols for unified atomic mass unit (u) and Dalton (Da) are equally valid in mass spectrometry.
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uniform resource identifier a type of formatted identifier that encapsulates the name of an Internet object, and labels it with an identification of the name space, thus producing a member of the universal set of names in registered name spaces and of addresses referring to registered protocols or name spaces (RFC 2828; RFC 1630) Project: AUTO09
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uniform resource locator a type of formatted identifier that describes the access method and location of an information resource object on the Internet (RFC 2828; RFC 1738) Project: AUTO09
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uniformity of coverage the consistency of coverage across a defined region of the genome Project: MM09 NOTE: Sufficient depth of coverage and uniformity of coverage are important properties for deriving high-quality sequencing data.
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uninterrupted power supply (UPS) battery backup system that safeguards against power fluctuations that can cause damage and/or loss of information by controlling the power going to equipment
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uninterruptible power source battery back-up system that safeguards against power fluctuations that can cause damage and/or loss of information by controlling the power going to equipment Project: GP36 NOTE: The uninterruptible power source usually provides power for only a short period of time, long enough for the supplied device to be powered down safely or for backup power from another source to be established or activated.
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uniplex an assay for a single target
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unique patient identifier a name or number that can uniquely identify a patient when at least two such identifiers are used Project: AUTO12 NOTE: The patient’s name is considered the primary unique patient identifier. In combination with the patient’s name, a unique number such as the medical record number, financial/account number, or episode number is also used.
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unit (of measurement) particular quantity, defined and adopted by convention, with which other quantities of the same kind are compared in order to express their magnitudes relative to that quantity
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unit a chosen reference quantity, which may be used for comparison of quantities of the same dimension; for example, millimeter for lengths, kilogram for mass, mole for amount of substance, gram per liter for mass concentration (IUPAC/IFCC197-3.3) Project: DI01
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unit equation mathematical relation between base units, coherent derived units, or other measurement units (JCGM 200:2012) Project: ISO IEC Guide 99 EXAMPLE 1: For the quantities in Example 1 of item 1.22, [Q1] = [Q2] [Q3] where [Q1], [Q2], and [Q3] denote the measurement units of Q1, Q2, and Q3, respectively, provided that these measurement units are in a coherent system of units (JCGM 200:2012); EXAMPLE 2: J := kg m2/s2, where J, kg, m, and s are the symbols for the joule, kilogram, metre, and second, respectively. (The symbol := denotes "is by definition equal to" as given in the ISO 80000 and IEC 80000 series.) (JCGM 200:2012); EXAMPLE 3: 1 km/h = (1/3.6) m/s (JCGM 200:2012).
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unit of blood the volume of blood, or one of its components, obtained from a single donor collection
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unit use (reagent) a component of a testing system that contains reagent(s) necessary to test a single sample.
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United Nations certified container packaging material (usually a cardboard box) that has passed UN manufacturing standards and is labeled by the manufacturer as such for the transport of certain dangerous goods Project: M29
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unit-use system testing system in which reagents, calibrators, and wash solutions are typically segregated as one test, without interaction of reagents, calibrators, and wash solutions from test to test, and the container in which the test is performed is always discarded after each test
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unit-use test system in vitro diagnostic medical device in which reagents, calibrators, sample conduits, vessels, and other reaction components supplied in a disposal carrier require no user preparation before the analysis and are used in the examination of a single sample Project: EP18, EP23
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universal location identifier data element in a CLSI AUTO14-compliant bar code for the laboratory that generated the first label for the specimen. See Subchapter 4.2.13 for details Project: AUTO14
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universal precautions set of precautions designed to reduce risk of transmission of HIV, hepatitis B virus, and other bloodborne pathogens in the health care setting Project: M29, GP17, QMS28 NOTE 1: All human blood; other body fluids containing visible blood; semen; vaginal secretions; tissue; and cerebrospinal, synovial, pleural, peritoneal, pericardial, and amniotic fluid are considered potentially infectious under standard precautions; NOTE 2: Universal precautions do not apply to feces, nasal secretions, saliva (except in a dental setting), sputum, sweat, tears, urine, and vomitus unless they contain visible blood; NOTE 3: Universal precautions applies to specific body fluids that are more likely to harbor blood-borne pathogens; this term was used in OSHA documents in the early 1990s and is still used in some OSHA documents; NOTE 4: Universal precautions is an approach to infection control. According to the concept of universal precautions, all human blood and certain human body fluids are treated as if known to be infectious for HIV, hepatitis B virus, and other bloodborne pathogens (21 CFR 1910.1030).
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unsatisfactory performance In proficiency testing, the failure to attain the minimum satisfactory score for an analyte, test, subspecialty, or specialty for a testing event (US CFR493 February 28, 1992).
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unshielded twisted pair the type of CAT-5 cabling used in POCT01 Project: POCT01
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unstable CGM sensor an unstable continuous glucose monitor sensor exhibits significant change in sensitivity or noise over time NOTE: A change in the output signal is not closely related to a change in the glucose concentration.
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unsuccessful performance In proficiency testing, the failure to attain the minimum satisfactory score for an analyte, test, subspecialty, or specialty for two consecutive or two of three consecutive testing events (US CFR493 February 28, 1992)
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unweighted pair group method with arithmetic mean a simple bottom-up data clustering method used in bioinformatics for the creation of phylogenetic trees Project: MM18
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upper limit of quantitation the largest amount of a substance that can be measured accurately Project: EP34 NOTE 1: It is the highest concentration value at which the measurement procedure achieves a specified level of accuracy and maintains a linear relationship between measurand values and the measurement procedure’s results; NOTE 2: The upper end of the analytical measuring interval; NOTE 3: The upper limit of quantitation is determined without dilution, concentration, or pretreatment not part of the process established to take measurements within the analytical measuring interval.
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upper limit of the measuring interval the highest measurand concentration at which all defined performance characteristics of the measurement procedure are met Project: C62, C57
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urinal a vessel for receiving urine Project: PRE05
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US Food and Drug Administration 510(k) clearance authorization by the US Food and Drug Administration to allow the sale of a device in the United States Project: M52
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US National Biological Standard a preparation that has been calibrated in international units against the World Health Organization (WHO) International Standards or Preparations Project: DI01
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USA100, USA300 two examples of pulsed-field gel electrophoresis strain types established by the Centers for Disease Control and Prevention in the United States for monitoring the spread of methicillin-resistant Staphylococcus aureus (MRSA) isolates. Although the USA strain types (designated USA100 through USA1200) were developed primarily to characterize MRSA strains, some methicillin-susceptible S. aureus isolates share the same pulsed-field patterns Project: M55
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usability the ease with which a user can learn to operate, prepare inputs for, and interpret outputs of a system or component (IEEE 610.12-1990) Project: AUTO08
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use error act or omission of an act that has a different medical device response to that intended by the manufacturer or expected by the operator (ISO 18113-1)
Project: ISO 18113-1, ISO 18113-2, ISO 18113-3 NOTE 1: Use error includes slips, lapses, and mistakes (ISO 18113-1); NOTE 2: IEC 62366:2007, Annex B and D.1.3, give a discussion and examples of use errors (ISO 18113-1).
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use error act or omission of an act that has a different medical device response than that intended by the manufacturer or expected by the operator Project: EP23 NOTE: User action or lack of user action using the medical device that leads to a different response intended by the manufacturer or expected by the user.
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use error act or omission of an act that results in an aberrant medical device response to that intended by the manufacturer or expected by the medical device operator Project: POCT13
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user the laboratory or person using the system Project: I/LA33 NOTE: For the purposes of this document, “system” refers to automated system.
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user the facility or person using the system Project: AUTO13
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user the laboratory or person using the measuring system Project: EP23 NOTE: Person interacting with (operating or handling) the medical device.
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user account an agreement allowing the use of a particular computer system, website, etc. Project: AUTO11
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user adjustment (of a measuring instrument) adjustment employing only the means at the disposal of the user
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user adjustment of blood glucose monitoring system procedure described in the instructions for use in which the user enters a number, uses a code strip or code chip, etc., so that the system achieves acceptable performance characteristics Project: ISO15197 (April 2001)
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user compliance ability and willingness of the user of a measuring system to adhere to and operate within the defined specifications of a measurement procedure (ISO 17593) Project: ISO 17593
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user manual information supplied for use with an instrument containing instructions for the proper use and for the safe and correct operation, maintenance and basic troubleshooting of the instrument (EN 592, p. 3) Project: ISO15197 (April 2001)
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user manual information supplied by the manufacturer concerning the proper use of an in vitro diagnostic medical device system, including the safe and correct operation, maintenance, and basic troubleshooting of the instrument Project: ISO 17593 (January 2002)
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utilities services, such as gas, electricity, water, drainage, telephone, and data
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utility assessment of usefulness and importance when different possible disparate outcomes are considered together allowing the attachment of values to outcome Project: ISO15196 (June 2001)
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utility value or benefit assigned to a particular outcome or state, such as clinical utility Project: GP10
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vacuole cavity in the cytoplasm of a cell that may contain ingested bacteria, yeast cells, or debris; excess vacuolization can be found in poorly preserved organisms or multiple vacuoles can be found in poorly preserved organism; vacuole contents and/or morphology may be helpful in identification of some of the intestinal protozoa (Entamoeba spp., Iodamoeba bütschlii) Project: M28
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validation verification, where the specified requirements are adequate for an intended use (JCGM 200:2012) Project: JCGM 200:2012, C34, C43, ISO 18113-1, H26, POCT07, MM06, H02, M53, MM19, NBS05, C51, MM14, EP09, C40, I/LA26, EP06, POCT06, H48, C64, EP34, MM17, M24, NBS09, NBS10 EXAMPLE 1: A measurement procedure, ordinarily used for the measurement of mass concentration of nitrogen in water, may be validated also for measurement of mass concentration of nitrogen in human serum (JCGM 200:2012); EXAMPLE 2: A measurement procedure for creatinine concentration in human serum can also be validated for the measurement of creatinine concentration in human urine (ISO 18113-1); EXAMPLE 3: A claims verification conducted by the manufacturer for the purpose of validating that the measurement procedure is fit for the purpose of quantitatively determining the concentration of a measurand in a medical laboratory setting; NOTE 1: Confirmation, through the provision of objective evidence, that the requirements for a specific intended use or application have been fulfilled (ISO 9000); NOTE 2: Validation can also be defined as the action (or process) of proving that a procedure, process, system, equipment, or method used works as expected and achieves the intended result; NOTE 3: The term “validated” is used to designate the corresponding status (ISO 9000); NOTE 4: The use conditions for validation can be real or simulated (ISO 9000); NOTE 5: A term used by the US Food and Drug Administration to describe a study that determines whether a test system meets user needs; NOTE 6: The components of validation are quality control, proficiency testing, validation of employee competency, instrument calibration, and correlation with clinical findings; NOTE 7: The intended use or user’s needs are external to the measuring system and independent of it, whereas a performance characteristic is part of the measuring system or measurement procedure, ie, it is internal to the measuring system; NOTE 8: Includes determination of performance characteristics (ie, accuracy, precision, sensitivity, specificity); NOTE 9: A one-time process completed to determine or confirm test performance characteristics before the test system is used for patient testing; NOTE 10: An external claims verification conducted by the manufacturer for the purpose of validating that the measurement procedure is fit for the purpose of quantitatively determining the concentration of a measurand in a medical laboratory setting is an example of a validation; NOTE 11: Confirmation by examination and provision of objective evidence that the particular requirements for a specific intended use can be consistently fulfilled (21 CFR 820.3); NOTE 12: Validation is the establishment and/or confirmation, through extensive testing, of the analytical and/or clinical performance characteristics of the measurement procedure; NOTE 13: It is primarily the manufacturer’s responsibility to ensure that design goals are met and performance claims are stated for a commercially developed assay or device, and a laboratory’s responsibility for a laboratory-developed test; NOTE 14: The validation of an extended measuring interval is performed through internal, analytical testing of the measurement procedure by its in vitro diagnostic test developer. This is often called “design verification”; NOTE 15: Characterizing the performance of a laboratory-developed test is a “validation” process; NOTE 16: The World Health Organization defines validation as “the action (or process) of proving that a procedure, process, system, equipment, or method used works as expected and achieves the intended result”; NOTE 17: An ongoing process that addresses the elements of maintaining a verified assay, including quality control, proficiency testing, employee competency, instrument calibration, and correlation with clinical findings; NOTE 18: Validation is required to establish the performance characteristics of a test system before use in a clinical application, if the test was not validated as part of a regulatory approval process; NOTE 19: See verification.
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validation in bacterial strain typing, the process by which the reproducibility and discriminatory power of new typing methods are shown to be appropriate for resolving epidemiologic relatedness among isolates Project: MM11 NOTE: In the context of bacterial strain typing, there is currently no consensus regarding the levels of discriminatory power and reproducibility required for this purpose or the process for demonstrating a particular level of performance; in Section 5.3 of CLSI document MM11, specific criteria are proposed.
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validation confirmation, through the provision of objective evidence, that the requirements for a specific intended use or application have been fulfilled (ISO 9000) Project: AUTO13, QMS07, QMS01, I/LA34, MM07, M33, H54, GP26, QMS13, MM13, MM10, MM03, H49, EP07, I/LA02, MM12, C24, MM01, GP40, AUTO10, AUTO08, EP10, C49, M50, C50, H58, POCT02, POCT05, MM11, I/LA21, H57, I/LA33, M55, GP33, H26, I/LA28, GP34, C58, C56, MM20, POCT05, MM22, PRE01, H60, C62, AUTO11, C57, MM23, MM21, EP33, POCT14, POCT17, QMS21, POCT04, QMS24, I/LA20, M58, EP31, C63, QMS22, EP32, QMS23, MM24, POCT16 Source: Quality Glossary NOTE 1: The word “validated” is used to designate the corresponding status (ISO 9000); NOTE 2: The use conditions for validation can be real or simulated (ISO 9000); NOTE 3: A term used by the FDA for a study used to determine whether a test system meets user needs (modified from 21 CFR Part 820); NOTE 4: Validation is also defined as the action (or process) of proving that a procedure, process, system, equipment, or method used works as expected and achieves the intended result; NOTE 5: The components of validation are quality control, proficiency testing, validation of employee competence, instrument calibration, and correlation with clinical findings; NOTE 6: Examples include validation of the process to use a new diagnostic tool, such as a new mammography instrument, automated laboratory test system or information system, automated medication dispensing system, or a new pulmonary function assessment device; information system; or evidence-based medicine; NOTE 7: a) Example: Validation of the performance of a new diagnostic tool such as an internally developed, analyte-specific method or reagents, or a laboratory-developed information system; b) Manufacturers are required to validate instruments and methods before market release (eg, FDA approval or European CE mark); NOTE 8: Manufacturers are required to validate instruments and methods before market release, eg, FDA approval or European CE mark; Example: Validation of the performance of a new diagnostic tool or a laboratory-developed information system; NOTE 9: Manufacturers are required to validate equipment before market release, eg, FDA approval or European CE mark; NOTE 10: Establishing documented evidence that provides a high degree of assurance that a specific process will consistently produce a product meeting its predetermined specifications and quality attributes (FDA); NOTE 11: Some of the components of validation are performance characteristics (eg, linear range, reproducibility, recovery, accuracy), quality control, proficiency testing, validation of employee competency, instrument calibration, and correlation with clinical findings; NOTE 12: Confirmation by examination and provision of objective evidence that the particular requirements for a specific intended use can be consistently fulfilled (FDA Quality System Regulation, 21 CFR 820.3); NOTE 13: As used in CLSI document I/LA21, validation includes performance verification; NOTE 14: Includes determination of performance characteristics (ie, accuracy, precision, sensitivity, specificity); NOTE 15: A one-time process completed to determine or confirm test performance characteristics before the test system is used for patient testing; NOTE 16: For the purpose of this guideline, validation is defined as establishing recorded evidence that provides a high degree of assurance that a specified process will consistently produce an outcome meeting its predetermined specifications and quality attributes; NOTE 17: In the context of CLSI document H26, and within the clinical laboratory environment, validation is primarily a manufacturer’s responsibility to ensure that design goals are met and performance claims are stated; NOTE 18: In the United States, the FDA has defined validation of a finished medical product in the context of the Quality System Regulation, 21 CFR § 820, as follows: 21 CFR § 820.3(z): “Validation means confirmation by examination and provision of objective evidence that the particular requirements for a specific intended use can be consistently fulfilled. (1) Process validation means establishing by objective evidence that a process consistently produces a result or product meeting its predetermined specifications. (2) Design validation means establishing by objective evidence that device specifications conform to user needs and intended use(s).”; NOTE 19: Examples include validation of the process to use a new diagnostic tool, such as an automated laboratory test system; information system; or evidence-based medicine; NOTE 20: It is primarily the manufacturer’s responsibility to ensure that design goals are met and performance claims are stated for a commercially developed assay or device, and a laboratory’s responsibility for a laboratory-developed test; NOTE 21: The process of demonstrating that the system under consideration meets, in all respects, the specification of that system; NOTE 22: Examples include validation of the process to use a new diagnostic tool, such as an automated laboratory test system or information system; NOTE 23: For the purposes of C63, establishment of the performance of a measurement procedure through the provision of objective evidence; NOTE 24: The objective evidence needed for a validation is the result of a test or other form of determination such as performing alternative calculations or reviewing documents (ISO 9000); NOTE 25: The action (or process) of proving that a procedure, process, system, equipment, or method used works as expected and achieves the intended result; NOTE 26: Validation is the establishment and/or confirmation by the developer, through extensive testing, of the analytical and/or clinical performance characteristics of the measurement procedure; NOTE 27: Validation can also be defined as the action (or process) of proving that a measurement procedure, process, system, equipment, or method used works as expected and achieves the intended result; NOTE 28: The World Health Organization defines validation as “the action (or process) of proving that a procedure, process, system, equipment, or method used works as expected and achieves the intended result”; NOTE 29: Verification, where the specified requirements are adequate for an intended use (JCGM 200:2012); NOTE 30: Validation is a phase in the Establishment Stage of the Test Life Phases Model.
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validation the activities performed at specific times to ensure that a testing system continues to give the correct results Project: POCT08, POCT15 NOTE: Because the terms “validation” and “verification” are similar in meaning, their definitions are often confused. However, because of CLSI’s commitment to global harmonization of terminology, we define the terms in the spirit of the International Organization for Standardization.
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validation a phase in the Establishment Stage of the Test Life Phases Model; verification, in which the specified requirements are adequate for an intended use (JCGM 200:2012) Project: EP12, EP25 NOTE 1: Confirmation, through the provision of objective evidence, that requirements for a specific intended use or application have been fulfilled (ISO 9000); NOTE 2: Validation is the establishment and/or confirmation by the developer, through extensive testing, of the analytical and/or clinical performance characteristics of the test method; NOTE 3: The performance evaluations performed by the developer to establish that performance is adequate for the intended use.
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validation confirmation that the specified requirements are adequate for an intended use (modified from JCGM 200:2012) Project: MM09 NOTE 1: The action (or process) of proving that a procedure, process, system, equipment, or method used works as expected and achieves the intended result; NOTE 2: Includes determination of performance characteristics (eg, accuracy, precision, sensitivity, specificity).
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validation a phase in the Establishment Stage of the Test Life Phases Model Project: EP19, EP45 NOTE: Validation is the establishment and/or confirmation by the developer, through extensive testing, of the analytical and/or clinical performance characteristics of the test method.
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validation plan a written document that describes the required validation activities and acceptance criteria Project: AUTO10, I/LA33 NOTE 1: Validation plans are customized for each type of hardware/software that needs to be validated and should be approved by the laboratory director prior to initiation; NOTE 2: Validation plans are customized for each type of hardware/software that needs to be validated and should be approved by the laboratory director prior to initiation; NOTE 3: For the purpose of this document, “hardware/software” refers to the automated system.
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validation protocol a written plan stating how validation will be conducted, including test parameters, product characteristics, production equipment, and decision points on what constitutes acceptable test results Project: I/LA33 NOTE: See test plan.
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validation summary the summarized, documented results of the validation plan Project: AUTO10, I/LA33
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validator the person who assumes the overall responsibility for the clinical validation and reporting of an order or an order group Alternate Term: clinical expert Project: AUTO16 NOTE 1: HL7® v2.5 speaks of “result principal interpreter”; NOTE 2: In HL7® Clinical Document Archictecture Release 2, this actor is playing the role of “authenticator” of the laboratory report or of a subset of this report; NOTE 3: Also “medical expert,” “biomedical scientist,” or “results principal interpreter.”
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validity the degree to which the inference drawn from a study is warranted when account is taken of the study methods, the representativeness of the study sample, and the nature of the population from which it is drawn Alternate Term: study validity Project: GP45 NOTE: Two varieties of study validity are distinguished: 1) Internal validity: The index and comparison groups are selected in such a manner that the observed differences between them on the dependent variables under study may, apart from sampling error, be attributed only to the hypothesized effect under investigation; 2) External validity (generalizability): A study is externally valid, or generalizable, if it can produce unbiased inferences regarding a target population (beyond the subjects in the study). This aspect of validity is only meaningful with regard to a specified external target population. For example, the results of a study conducted using only white male subjects might or might not be generalizable to all human males, or to human females. The evaluation of generalizability usually involves much more subject-matter judgment than internal validity.
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value an element of the organizational-wide direction phase of plans management that delineates a professional principle, ethic, or belief that is important to satisfying customer needs, including quality expectations
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value (of a quantity) magnitude of a particular quantity generally expressed as a unit of measurement multiplied by a number; EXAMPLES: a) length of a rod: 5,34 m or 534 cm; b) mass of a body: 0,152kg or 152g; c) amount of substanceof a sample of water (H2O): 0,012 mol or 12 mmol NOTES: 1) The value of a quantity may be positive, negative or zero; 2) The value of a quantity may be expressed in more than one way; 3) The values of quantities of dimension one are generally expressed as pure numbers; 4) A quantity that cannot be expressed as a unit of measurement multiplied by a number may be expressed by reference to a conventional reference scale or to a measurement procedure or to both.
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value See quantity value Alternate Term: quantity value; value of a quantity Project: C51
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value a principle, standard, or quality considered worthwhile or desirable to a person or an organization Project: QMS16
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value of a quantity See quantity value Alternate Term: quantity value; value Project: C51
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value stream mapping a lean manufacturing technique used to analyze the flow of materials and information currently required to bring a product or service to a consumer
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value transfer protocol a formal plan for carrying out the assignment of analyte values to a reference material from a reference material of higher order Project: I/LA24
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variability extent to which data points (minimal inhibitory concentration, zone diameter) over a distribution are dispersed due to technical, biological, or other factors. Technical variability may originate from both operator-dependent factors (eg, inoculum preparation, plate streaking, reading precision) and operator-independent factors (eg, variations in materials [eg, media lot, agar plate depth, antibiotic disk manufacturer] or incubation conditions) Project: M23 NOTE: Biological variability reflects the natural fluctuation of a measured parameter, such as minimal inhibitory concentration or zone diameter, around a mean value and originates from factors such as genetic background or metabolic state of the tested isolate.
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variable a quantity or function that may assume a given value and/or set of values (RHUD1.7CD)
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variable the symbol representing the quantity or function (RHUD1.7CD)
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variable air volume air supply and exhaust system in which the airflow requirements increase or decrease to provide only as much air as is required
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variable cost cost that varies depending on volume, ie, cost rises as volume increases and falls as volume decreases Project: GP49
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variable number of tandem repeats any polymorphic locus consisting of repeat units of any size (usually microsatellites or minisatellites) Project: MM12 NOTE 1: Originally, this term was synonymous with minisatellite repeats, which consist of tandemly arranged repeating units of 30 to 35 base pairs; NOTE 2: The repeat unit of a variable number of tandem repeats (minisatellite) has a variable sequence, but contains a core sequence of 10 to 15 base pairs; NOTE 3: A specific locus can be highly polymorphic, having numerous alleles which differ in the number of repeat units.
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variable number tandem repeats originally, this term was synonymous with minisatellite repeats, which consist of tandemly arranged repeating units of 30 to 35 base pairs Project: MM01 NOTE: The repeat unit of a variable number tandem repeat (minisatellite) has a variable sequence but contains a core sequence of 10 to 15 base pairs; a specific locus can be highly polymorphic, having numerous alleles that differ in the number of repeat units.
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variable region a stretch in a gene sequence known to harbor diversity (eg, between species) Project: MM18 NOTE: There can be multiple variable regions in a gene sequence, not necessarily located at the same distinct positions for all genera.
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variance a measure of dispersion of observations in a sample or population, which is the sum of the squared deviations of observations from their average divided by the degrees of freedom Project: QMS24 NOTE: Usually, the degrees of freedom equals} one less than the number of observations (ISO 3534-1-2.33); 1) corrected variance - a statistical manipulation that adjusts a variance value by subtracting components from other sources of variance.
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variance the expectation of the square of the centered random variable (ISO 3534-1 § 1.22) Project: C51 NOTE: The expected variance of measurements of the quantity x is symbolized σ 2x or σ 2(x).
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variant • benign variant – a DNA sequence that is not associated with clinically recognized disease
• pathogenic variant – a DNA sequence that is associated with a deleterious outcome
• variant // genetic variant – any alteration in a gene from its natural state (wild type) Alternate Term: genetic variant Project: NBS09 (for variant or genetic variant) NOTE 1: In NBS09, “variant” refers to a DNA sequence that varies from a reference DNA sequence in the ABCD1 gene; NOTE 2: Variants may be disease causing or benign; NOTE 3: Also called “mutation”; NOTE 4: See benign variant and pathogenic variant.
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variant any alteration in a gene from its natural state Alternate Term: genetic variant Project: MM17, MM19, MM09, NBS05, NBS10 NOTE 1: May be disease causing or benign; NOTE 2: “Variant” is also referred to as “mutant”; NOTE 3: In NBS05, a genetic variant may be cystic fibrosis–causing (pathogenic), varying clinical consequence, non–cystic fibrosis–causing (likely benign or benign), or a variant of unknown significance; NOTE 4: See benign variant, pathogenic variant, and pathogenic variant with varying clinical consequences; NOTE 5: See pathogenic variant; NOTE 6: Refers to any DNA change, regardless of clinical implication, population frequency, or origin (ie, somatic vs inherited).
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variant a DNA sequence variation, frequently producing abnormal gene function and associated with disease or predisposition to disease. Some variants are termed conservative because the amino acid substitution has little or no effect on the protein function Project: MM01 NOTE: Variants are usually distinguished from polymorphisms, which are also genetic sequence variants but are present at a frequency of at least 1% in a population. Polymorphisms may also be associated with abnormal gene expression or function.
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variant an alteration in DNA sequence, whose molecular and clinical consequences are not established, which could range from having no consequences to deleterious or beneficial consequences Project: MM24
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variant call format file computer file created in next-generation sequencing bioinformatics pipelines by variant calling software packages. It describes genetic variants by comparison with a reference genome sequence Project: MM26
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variation (due to an influence quantity) difference in indication for a given measured quantity value, or in quantity values supplied by a material measure, when an influence quantity assumes successively two different quantity values (JCGM 200:2008) Project: ISO IEC Guide 99
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vascular access device a device inserted temporarily or permanently into a vein or artery to enable access to the circulatory system for the administration of intravenous fluids or medications, or for various procedures Project: H21 NOTE: Examples include central venous lines for hyperalimentation or chemotherapy and arteriovenous shunts for hemodialysis.
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vascular access device a device inserted temporarily or permanently into a vein and/or artery to enable access to the circulatory system for the administration of fluids or medications, or for various procedures Project: GP48, PRE02
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vendor the supplier or manufacturer of the device; a supplier of automated systems and/or associated products and/or services Project: AUTO09, I/LA33 NOTE: A vendor may or may not be the manufacturer of the automated system.
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vendor the hardware/software firm or personnel responsible for development, installation, training, or maintenance of the product or service Project: AUTO13
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venipuncture puncture of a vein Project: M47
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venipuncture the puncture of a vein for surgical or therapeutic purposes, or for collecting blood specimens for analysis Project: POCT14, PRE02
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venipuncture the procedures for collecting a blood sample from a vein Project: POCT04 NOTE: This blood is called "venous blood."
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venipuncture the puncture of a vein for therapeutic purposes, or for collecting blood specimens for analysis Project: GP48
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venipuncture/venepuncture the puncture of a vein for surgical or therapeutic, purposes, or for collecting blood specimens for analysis (RHUD1.7CD) Project: H49
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venous blood deoxygenated blood found in the veins that is high in carbon dioxide having released oxygen and absorbed CO2 in the tissues Project: GP39
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venous blood sample blood collected after directly puncturing a vein, usually with a needle and syringe, or another collection device (ISO 17593) Project: ISO 17593 NOTE: Venous blood may be collected without additives such as anticoagulants or preservatives, and if so, will be inherently unstable; venouse blood may also be collected in containers containing additives or preservatives with the intent to stabilize specific components (ISO 17593).
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venous thromboembolism term commonly used for the closely linked conditions of deep vein thrombosis and pulmonary embolism Project: H49, POCT14
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venous thromboembolism a thrombus (blood clot) or embolus in the venous circulation Project: H59
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ventilation movement of air into and out of a space
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ventricular shunt fluid ventricular shunts are placed for the treatment of hydrocephalus to remove fluid from the ventricles and provide drainage to another site (eg, the peritoneal cavity) Project: H56 NOTE: The fluid that fills the shunt is designated ventricular shunt fluid.
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verification provision of objective evidence that a given item fulfills specified requirements (JCGM 200:2012) Project: QMS01, MM13, C34, I/LA33, C43, H26, MM06, H02, M53, MM19, C51, EP17, EP27, EP09, EP26, C40, I/LA26, MM09, EP06, POCT06, PRE01, H48, C64, EP34, MM17, QMS22, C49, M24, NBS09, NBS05, EP35, NBS10 Source: Quality Glossary EXAMPLE 1: Confirmation that a given reference material as claimed is homogeneous for the quantity value and measurement procedure concerned, down to a measurement portion having a 10-mg mass (JCGM 200:2012); EXAMPLE 2: Confirmation that performance properties or legal requirements of a measuring system are achieved (JCGM 200:2012); EXAMPLE 3: Confirmation that a target measurement uncertainty can be met (JCGM 200:2012); EXAMPLE 4: Results obtained from using an examination method exactly as validated by the manufacturer without any deviation; NOTE 1: When applicable, measurement uncertainty should be taken into consideration (JCGM 200:2012); NOTE 2: The item may be, eg, a process, measurement procedure, material, compound, or measuring system (JCGM 200:2012); NOTE 3: The specified requirements may be, eg, that a manufacturer’s specifications are met (JCGM 200:2012); NOTE 4: Verification in legal metrology, as defined in VIML (OIML V1:2000), and in conformity assessment in general, pertains to the examination and marking and/or issuing of a verification certificate for a measuring system (JCGM 200:2012); NOTE 5: Verification should not be confused with validation or calibration. Not every verification is a validation (JCGM 200:2012); NOTE 6: In chemistry, verification of the identity of the entity involved, or of activity, requires a description of the structure or properties of that entity or activity (JCGM 200:2012); NOTE 7: Confirmation, through the provision of objective evidence, that specified requirements have been fulfilled (ISO 9000); NOTE 8: For the purposes of I/LA33 and C64, verification is defined as confirmation by examination and provision of objective evidence that specified requirements have been met; NOTE 9: In the context of CLSI document H26, verification is the end-user laboratory’s responsibility to ensure that manufacturers’ claims are correct; NOTE 10: A one-time process completed to determine or confirm test performance characteristics before the test system is implemented; NOTE 11: An activity completed to determine or confirm examination performance characteristics before the examination system is used for examinations; NOTE 12: Verification is a process completed to confirm test performance characteristics before the test system is used for patient testing; NOTE 13: For a laboratory measurement procedure, verification is the confirmation through testing that the performance characteristics of the measurement procedure are consistent with established label claims. Verification is normally performed by the end user before measurement procedure implementation for routine use in the laboratory; NOTE 14: Although “verification” may be used to describe actions performed by either the end user or the manufacturer, eg, to demonstrate acceptable performance specifications, EP19 uses verification to refer to confirmation of acceptable performance by the end user of a measurement procedure; NOTE 15: The verification of an extended measuring interval is performed through testing in the laboratory implementing the measurement procedure; NOTE 16: Confirming the performance of a regulatory organization–cleared or –approved assay is a “verification” process; NOTE 17: The ongoing process that confirms specified requirements (predetermined by validation) are fulfilled; NOTE 18: In the context of MM06, this is an end-user (clinical laboratory) responsibility to confirm that manufacturer’s claims are met on the specific device in its hands, and also that medical needs are met; NOTE 19: Regulations require that laboratories ensure or verify performance specifications before the test system is used for clinical purposes. Although the terms validation/verification are commonly used interchangeably, the key difference with respect to MM06 is whether a test system has been validated or established by the manufacturer, cleared or approved by the US Food and Drug Administration (FDA), and implemented in a laboratory without modification. FDA-cleared or FDA-approved test systems have been validated by the manufacturer; therefore, a laboratory using this system would need to verify (or confirm) performance specifications in their laboratories. A laboratory would need to validate (or establish) performance specifications for an FDA-modified or laboratory-developed test, which would include accuracy, precision, sensitivity, specificity, and measuring range, as applicable.
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verification a phase in the Implementation Stage of the Test Life Phases Model; provision of objective evidence that an item fulfills specified requirements (JCGM 200:2012) Project: EP12, EP25 NOTE 1: Confirmation, through the provision of objective evidence, that specified requirements have been fulfilled (ISO 9000); NOTE 2: For a laboratory test method, verification confirms through testing that the performance characteristics of the test method are consistent with established claims. The Verification Phase is normally performed by the end user as part of implementation for routine use in the laboratory.
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verification the activities performed before a testing system is put into use to ensure that the testing system gives the correct results Project: POCT08, POCT15 NOTE: Because the terms “validation” and “verification” are similar in meaning, their definitions are often confused. However, because of CLSI’s commitment to global harmonization of terminology, we define the terms in the spirit of the International Organization for Standardization.
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verification a phase in the Implementation Stage of the Test Life Phases Model Project: EP19, EP45 NOTE: For a laboratory test method, verification is the confirmation through testing that the performance characteristics of the test method are consistent with established claims. The Verification Phase is normally performed by the end user as part of implementation for routine use in the laboratory.
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verification confirmation, through the provision of objective evidence, that specified requirements have been fulfilled (ISO 9000) Project: AUTO11, MM23, EP10, GP40, MM22, POCT14, MM01, POCT16 NOTE 1: A one-time process completed to determine or confirm test performance characteristics before the test system is used for patient testing; NOTE 2: The ongoing process that confirms specified requirements (predetermined by validation) are fulfilled; NOTE 3: In the context of MM22, this is an end-user (medical laboratory) responsibility to confirm that manufacturer’s claims are met on the specific device being used, and also that medical needs are met; NOTE 4: For a laboratory test method, verification is the confirmation through testing that the performance characteristics of the test method are consistent with established claims. The Verification Phase is normally performed by the end user as part of the implementation for routine use in the laboratory; NOTE 5: Provision of objective evidence that a given item fulfills specified requirements (JCGM 200:2012); NOTE 6: For example, an entity’s requirements have been correctly defined, or an entity’s attributes have been correctly presented, or a procedure or function performs as intended and leads to the expected outcome; NOTE 7: The word "verified" is used to designate the corresponding status (ISO 9000); NOTE 8: Confirmation can comprise activities such as: performing alternative calculations; comparing a new design specification with similar proven design specifications; undertaking tests and demonstrations; and reviewing the document before issue; NOTE 8: The US Food and Drug Administration defines verification as "a study used to determine whether a test system meets specifications" (21 CFR Parts 808, 812, and 820).
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verification provision of objective evidence that a given item fulfills specified requirements (JCGM 200:2012); an activity completed to determine or confirm examination performance characteristics before the examination system is used for examinations Project: GP33, MM24 NOTE 1: The ongoing process that confirms specified requirements (predetermined by validation) are fulfilled; NOTE 2: In the context of MM24, it is an end-user’s (medical laboratory) responsibility to confirm that manufacturer’s claims are met on the specific device being used and also that medical needs are met; EXAMPLE: Results obtained from using an examination method exactly as validated by the manufacturer without any deviation (JCGM 200:2012).
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verifier the equivalent of a calibrator but used to verify calibration rather than for calibration per se Project: I/LA18 NOTE: Unlike a control, a verifier should have an absolute level designated (ie, not a range of acceptable values).
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vertical exit route used to escape a fire that moves in a vertical direction, such as a stair tower
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very late antigen, number 4 also known as CD49d, ligation of this α-integrin provides costimulatory activity to T-cells Project: I/LA26
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very long–chain fatty acid fatty acid with 22 or more carbon atoms Project: NBS09 NOTE: For the purpose of NBS09, fatty acids with 20 carbon atoms are also classified as very long–chain fatty acids.
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very low birth weight a birth weight of < 1500 g Project: NBS03
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very major discrepancy (VMD) test result by the reference method interpreted as R and an AST device result of S. Another representation of the concept: NVMD × 100/NRREF where NVMD is the number of tests that result in a VMD; NRREF is the number of resistant bacterial isolates as determined by the reference method (ISO 20776-2) Project: ISO 20776-2 NOTE: The overall VMD is expressed as a percentage (ISO 20776-2).
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very major discrepancy discrepancy in a test result when a new antimicrobial susceptibility testing system result is susceptible and an existing commercial antimicrobial susceptibility testing system result is resistant; see the following equation: % VMD = NVMD • 100/NR Project: M52 NOTE 1: Another representation of the concept: NVMD • 100/NR where NVMD is the number of tests that result in a very major discrepancy; NR is the number of resistant microbial isolates as determined by the comparator device; NOTE 2: “Discrepancy” is used in M52 when two systems are in disagreement, while “error” is used when the antimicrobial susceptibility testing system result does not agree with the reference method result.
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very major error error when the reference method result is resistant and the result from the antimicrobial susceptibility testing system under evaluation is susceptible. The percentage of very major error should be calculated for the resistant isolates as determined by the reference method only; see the following equation: % VME = NVME • 100/total isolates resistant by reference method Project: M52 NOTE: “Discrepancy” is used in M52 when two systems are in disagreement, while “error” is used when the antimicrobial susceptibility testing system result does not agree with the reference method result.
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vesicle terminal swelling of a conidiophore Project: M54
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viability percentage of cells in a population that are capable of continued life, as defined by some physical or functional measurement Project: H62
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viability dye a dye that may serve to identify nonviable cells by virtue of its ability to penetrate cells with damaged membranes and subsequently bind to double stranded nucleic acid Project: H42, H43 NOTE: Propidium iodide and 7-aminoactinomycin D are the most commonly used viability dyes. These viability dyes cannot be used as an indication of viability after fixation of cells by most methods because all cells become permeable and take up propidium iodide.
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vinyl composition tile a common flooring tile that is commonly supplied in one-foot square pieces
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viral culture the infection of cell cultures by viable (infectious) viral particles, usually resulting in viral replication Alternate Term: viral isolation Project: M41 NOTE: Cellular antigen expression (eg, cytomegalovirus early antigen) or a cytopathic effect resulting from viral toxicity (eg, some adenovirus cultures) may occur in the absence of viral replication.
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viral load the quantitative level of virus or viral nucleic acid in a specimen such as blood Project: MM10, MM24
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viral load the amount of virus, reflecting replication and clearance, in a sample from an infected individual. Quantification of viral nucleic acids in blood is commonly used as a marker of viral load. Blood may be an appropriate sample for some viruses (eg, HIV type 1), but not for others (eg, human papillomavirus) Project: MM06
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viral suppressor subset of chronically HIV infected individuals who spontaneously suppress or control HIV replication in the absence of antiretroviral therapy Project: M53 NOTE: Also known as “elite controllers” or “long term nonprogressors.”
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virtual assessment a review to determine compliance with specified requirements by means other than on-site visits (eg, video live streaming, screen sharing, e-mail, or other electronic communication) Project: QMS17 NOTE: Virtual assessments can be conducted by the laboratory or an external organization.
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virtual crossmatching prediction of crossmatch results based on accurate identification of HLA antibodies, which allows one to determine unacceptable and acceptable donor antigens Project: ILA29
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virtual private network a restricted-use, logical (ie, artificial or simulated) computer network that is constructed from the system resources of a relatively public, physical (ie, real) network (such as the Internet), often by using encryption (located at hosts or gateways), and often by tunneling links of the virtual network across the real network (RFC 2828) Alternate Term: VPN Project: AUTO09, POCT02
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virus checking the process by which incoming data are screened for computer viruses; may also be referred to as virus scanning Project: POCT02 NOTE: The typical process uses an antivirus program available from several companies.
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viscosity impedance (method of clot detection) detection based on the increase of the viscosity of the plasma being tested and measured through the motion of an object Project: H48 NOTE: When reagent is added, the object oscillates and amplitude is monitored. As the clot appears, the viscosity increases and the amplitude of motion decreases.
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vision an element of the organizational-wide direction phase of plans management that delineates a broad strategy to meet the paramount future customer needs with the managerial and operational resources of tomorrow
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vitamin K antagonists a class of compounds that, when taken orally, act as vitamin K antagonists and depending on the dose administered, result in diminished levels of functional factors II, VII, IX, and X giving an in vivo anticoagulant effect Alternate Term: AVK plasma Project: H54, H47, H57, H48 NOTE 1: The broad class of compounds are referred to as coumarins; NOTE 2: Previously termed coumarin-derived oral anticoagulant therapy.
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VLDL cholesterol cholesterol bound to a very low density lipoprotein
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voice of the customer process used to capture customer requirements and/or feedback and provide best-in-class service and/or product quality NOTE: This is a proactive, innovative process used to capture the changing requirements of the customers with time.
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voided urine urine that is excreted naturally through the urethra, without the aid of a device Project: PRE05
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volts a measure of the pressure in an electrical circuit
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volume fraction volume ratio of a component to the whole; In Immunoassay
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volume fraction of erythrocytes percentage of the formed cellular elements within a whole blood sample Alternate Term: hematocrit Project: ISO 17593 (January 2002) NOTE: Hematocrit may be expressed as a percentage (eg, 39%) or as a fraction (eg, 0.39).
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volume fraction of erythrocytes in blood proportion of packed cells in a blood sample (ISO 17593) Project: ISO 17593 NOTE 1: Expressed either as a fraction, often given as a percentage (conventional) of the SI unit (ISO 17593); NOTE 2: Sometimes referred to as "haematocrit" after the instrument originally used to estimate the volume fraction of erythrocytes in blood (ISO 17593).
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von Willebrand disease (vWD) a hereditary or acquired defect in the quantity and/or function of von Willebrand factor Project: H51
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von Willebrand factor (vWF) a high molecular weight, multimeric glycoprotein present in endothelial cells, megakaryocytes, platelets, and plasma Project: H51 NOTE: This protein is present in reduced amounts and/or is abnormal in von Willebrand disease.
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von Willebrand factor antigen (vWFAg) von Willebrand factor as measured by an immunologic assay Project: H51
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warm ischemia time the elapsed time between devascularization and removal of tissue from the body Project: MM13
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warning statement that alerts the user about a situation that, if not avoided, could result in serious adverse reactions and safety hazards from the use of a device Project: ISO CD 18113-1, ISO CD 18113-2, ISO CD 18113-3 NOTE 1: The designation of a hazard alert as a "warning" is reserved for the most significant consequences; NOTE 2: The distinction between warnings and precautions is a matter of degree of likelihood and seriousness of the hazard.NOTE 3 Use includes use errors and reasonably foreseeable misuse (see ISO 14971 and IEC 62366 for a discussion of these concepts).
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warning statement that alerts users about a situation that, if not avoided, could result in hazards or other serious adverse consequences from the use of an IVD medical device
Project: ISO 18113 NOTE 1: The designation of a hazard alert as a warning is reserved for the most significant consequences; NOTE 2: The distinction between a warning and a precaution (3.53) is a matter of degree, considering the likelihood and seriousness of the hazard (3.20); NOTE 3: Use includes use errors (3.71) and reasonably foreseeable misuse. See ISO 14971 and IEC 62366 for discussions of these concepts; NOTE 4: Adapted from US Food and Drug Administration, Guidance on Medical Device Patient Labelling; Final Guidance for Industry and FDA, 19 April 2001.
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waste a discarded material, no longer usable for its original purpose Project: GP05 NOTE: It may result from household or institutional activities (eg, garbage) or from biological activities (eg, excreta).
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waste segregation the segregation of wastes immediately on generation into different management categories Project: GP05
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watt 1) In electrical terms, one watt is the power produced by a current of one ampere flowing through an electric potential of one volt; 2) The power which in one second gives rise to energy of one joule Project: GP28 NOTE 1: The SI unit of power; power is the rate at which work is done, or (equivalently) the rate at which energy is expended; NOTE 2: One watt is equal to a power rate of one joule (force per distance) of work per second of time.
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watts a measure of electrical power that is determined by multiplying the voltage by the amperage
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wave-guide a device that delivers the microwave energy from the magnetron to the microwave cavity Project: GP28
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WBC white blood cells, leukocyte Project: H20
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weapons of mass destruction chemical, biological, radiological, nuclear, or explosive agents, capable of producing mass fatalities and casualties when deployed effectively Project: GP36
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weighted regression a parametric regression analysis technique that weights the influence of individual patient results based upon a predefined criterion Project: EP09 NOTE 1: Weighted regression is often applied to both least squares (y results weighted) and Deming (x and y results weighted) regressions; NOTE 2: The weighting scheme typically assigns influence to a result that is inversely related to its expected variance.
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wellness testing any diagnostic testing intended to aid in the recognition of asymptomatic/preclinical disease, or to confirm a state of health. Project: AST03
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WHO International Biological Reference Preparation the same as WHO International Biological Standards, except that they are not covered by resolutions of the World Health Assembly (ie, use in national control is not obligatory) Project: DI01
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WHO International Biological Standards WHO-certified reference materials that, usually as a result of an international consensus evaluation, have been assigned international units for quantification of the analyte NOTE: Member states of the World Health Assembly have agreed to subject their national quality control to existing WHO International Biological Standards and the associated international units or their equivalents
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WHO International Reference Reagents WHO-certified reagents established for qualitative use as specific antisera for the identification of microorganisms or their products Project: DI01
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whole blood blood containing all its cellular components that has not been centrifuged nor had its plasma or serum removed Project: POCT04
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whole blood blood that contains all of its cellular and plasma components Project: MM13
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whole blood blood containing all of its cellular and plasma components that has not been centrifuged or had its plasma or serum removed Project: POCT14, POCT13, POCT17 NOTE 1: It may be collected in an anticoagulant solution, with or without the addition of nutrients, (WHO BS/95.1793) or it may be derived directly from a capillary puncture; NOTE 2: In the context of POCT14, whole blood refers primarily to blood collected by capillary puncture; NOTE 3: For hematocrit studies, it may be necessary to manipulate whole blood specimens by centrifugation to achieve the desired hematocrit.
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whole blood equivalent a glucose result obtained from a whole blood glucose meter system that is calibrated to yield a result on the same sample that is equivalent to the result obtained on whole blood measured on a laboratory analyzer Project: POCT12
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whole blood lysis a method of specimen preparation where antibody reagents are added to an aliquot of whole blood and, following incubation, a lysing agent added to remove red blood cells Project: H42, H43 NOTE: A subsequent wash of the sample may be used to reduce background fluorescence, but should not be performed if absolute counting beads are added. The primary advantage of the method is that it allows interaction of the antibody reagent with cells in a near native state and minimizes sample handling.
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whole exome sequencing methods and procedures that determine the DNA nucleotide sequence of the exome, the protein-coding regions (exons) present in the genome of an organism or individual Project: NBS05
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whole genome sequencing methods and procedures that determine the complete (coding and noncoding) DNA sequence of an organism or individual Project: NBS05
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wick to draw blood away from the bleeding time incision by capillary action using a sheet of absorbent filter paper Project: H45
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wild type absence of acquired resistance mechanisms to the antimicrobial agent for a given strain (ISO 20776-1) Project: ISO 20776-1
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wild type describes isolates with minimal inhibitory concentrations below the epidemiological cutoff value Project: VET05, VET04 NOTE: An isolate defined as wild-type for a species can be assumed to lack any acquired or mutational resistance mechanisms to the drug in question.
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wild-type the normal (as opposed to the variant) gene or allele Project: MM17, MM09
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wild-type describes isolates with no mechanisms of acquired resistance or reduced susceptibility for the antifungal agent being evaluated Project: M57
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wild-type distribution the distribution of minimal inhibitory concentration/minimal effective concentration values of a given species with a given antifungal agent when there are no known mutational resistance mechanisms present in any species representatives Project: M57
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wild-type organism a strain that does not harbor any acquired resistance to the particular antimicrobial agent being examined Project: M51 NOTE: The typical minimal inhibitory concentration/minimal effective concentration distribution for wild-type organisms covers three to four twofold dilution steps surrounding the modal minimal inhibitory concentration/minimal effective concentration. For disk diffusion testing, the wild-type zone diameter profile is established by parallel testing of each antimicrobial agent by both minimal inhibitory concentration/minimal effective concentration and disk diffusion methods.
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window period See seroconversion window period Project: M53
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window period the period between detectable viral load and detectable antibody (with any given test) or between exposure and test positivity Project: POCT15 NOTE: The window period for a given test, rapid or conventional, depends on the test’s analytical sensitivity, the amount of material tested, the antibody classes detected (eg, immunoglobulin G, immunoglobulin M and immunoglobulin G), and antigens or other analytes detected in the particular test.
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wipe test a wipe paper (beta: foam; gamma: paper) used to wipe a potentially radioactive-contaminated surface NOTE: The presence of a radioisotope on the wipe paper is measured by a beta or gamma counter.
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wireless data transmission without the use of cabling, direct connections, or wires Project: POCT02 NOTE: There are several wireless standards for communications, such as IEEE 802.11.
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wireless local area network wireless local area network usually refers to wireless Ethernet networks based on the Institute of Electrical and Electronics Engineers 802.11 standard Project: AUTO09
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within range quality control results that are within preset limits
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within-device precision See intermediate precision conditions. Project: EP15
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within-group design a study design in which comparisons are made within a group of study subjects at two or more time periods during which the study subjects may have different environmental exposures, clinical treatments, or use of health services Project: GP45 NOTE 1: In observational studies, comparisons are made between two time periods when study subjects have different exposures, treatments, or use different health services; NOTE 2: Observational within-group designs are used when it is not feasible or ethically permissible to control the exposures, treatments, or use of health services; NOTE 3: In experimental studies, comparisons are made between two or more time periods when study subjects have been allocated, ideally at random, to different clinical treatments or the use of specific health services; NOTE 4: Within-group designs have an advantage in that fewer study subjects are needed and study subjects can serve as their own controls; NOTE 5: Within-group designs have the disadvantages that they may take longer to complete and are subject to potential bias due to patient conditions that may change over time, carry-over effects from previous interventions, or secular changes in the healthcare system.
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within-laboratory imprecision imprecision over a defined time and operators, within the same facility and using the same equipment. Calibration and reagents may vary Project: EP15 NOTE: Formerly, the term “total precision” was used in EP15.
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within-laboratory imprecision total imprecision of a measurement system, instrument, or manual test method in a single laboratory Project: EP26 NOTE: This is usually the combined effects of repeatability and different runs, days, and operators.
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within-laboratory precision precision over a defined time and operators, within the same facility and using the same equipment; calibration and reagents may vary NOTE: Formerly, the term total precision was used in EP15.
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within-reagent lot imprecision imprecision that includes within-run, between-run, and between-day sources of variation but excludes lot-to-lot variability Project: EP26
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within-run precision See intermediate precision conditions and within device precision. Alternate Term: repeatability Project: EP15
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within-subject variation variation in analyte concentrations within an individual over time or because of differences in patient preparation Project: C48 NOTE: This includes factors such as activity, fasting status, or short-term health status.
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within-unit homogeneity variation within one unit of a property of a reference material Project: EP30
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Wood's lamp an ultraviolet lamp used to detect fluorescence emitted by skin infected with certain fungi
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Wood's lamp an ultraviolet lamp used to detect fluorescence emitted by anaerobic microorganisms Project: M56
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work order the testing of a battery or a test requested by the order filler actor to the automation manager actor Project: AUTO16
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work order step an atomic operation on one biological specimen contributing to a work order on that specimen Project: AUTO16
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work practice controls Controls that reduce the likelihood of exposure by altering the manner in which a task is performed (eg, prohibiting recapping of needles by a two-handed technique) Project: X3-R
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work practice controls precautionary measures that reduce the likelihood of exposure to bloodborne pathogens by altering the way a task or procedure is performed Project: GP48
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workflow progression of tasks, events, or interactions that comprise a work process, involve two or more persons, and create or add value to the organization’s activities; in a sequential workflow, an activity is dependent on the activity that precedes it, and in a parallel workflow, two activities can take place concurrently Project: QMS02 NOTE: The laboratory’s path of workflow is sequential.
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working distance the distance between a bar code reader and the bar code Project: AUTO14
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working interval See measuring interval Alternate Term: measuring interval Project: C51, VET04
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working measurement standard measurement standard that is used routinely to calibrate or verify measuring instruments or measuring systems (JCGM 200:2012) Alternate Term: working standard Project: ISO IEC Guide 99 NOTE 1: A working measurement standard is usually calibrated with respect to a reference measurement standard (JCGM 200:2012); NOTE 2: In relation to verification, the terms "check standard" or "control standard" are also sometimes used (JCGM 200:2012).
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working measurement standard standard that is used routinely to calibrate or check material measures, measuring instruments, or reference materials (ISO 17511) Alternate Term: working standard, manufacturer's working calibrator Project: ISO 17511
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working method method that is intended for use in routine practice, having been shown by a validation study with a reference or standardized method to be sufficiently reliable for its intended (clinical) purpose Alternate Term: recommended selected method Project: H02
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working standard standard that is used routinely to calibrate or check material measures, measuring instruments or reference materials (VIM93) Project: ILA18 NOTE 1: A working standard is usually calibrated against a reference standard; NOTE 2: A working standard used routinely to ensure that measurements are being carried out correctly is called a check standard.
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workshop type of discussion-based exercise, representing the second tier of exercises in the building-block approach Project: GP36 NOTE 1: Although similar to seminars, workshops differ in two important aspects: increased participant interaction, and a focus on achieving or building a product (eg, plans, policies); NOTE 2: A workshop is typically used to: test new ideas, processes, or procedures; train groups in coordinated activities; and obtain consensus. Workshops often use breakout sessions to explore parts of an issue with smaller groups.
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X direction the direction that a specimen travels along a transportation system Project: AUTO02 NOTE: Specimens would move along the X dimension as, for example, in transportation from station to station in a laboratory.
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X.500 Directory an ITU-T Recommendation that is one part of a joint ITU-T/ISO multipart standard (X.500-X.525) that defines the X.500 Directory, a conceptual collection of systems that provide distributed directory capabilities for OSI entities, processes, applications, and services. (The ISO equivalent is ISO 9594-1 and related standards, ISO 9594-x.) The X.500 Directory is structured as a tree (the Directory Information Tree), and information is stored in directory entries. Each entry is a collection of information about one object, and each object has a DN. A directory entry is composed of attributes, each with a type and one or more values. For example, if a public-key infrastructure uses the Directory to distribute certificates, then the X.509 public-key certificate of an end user is normally stored as a value of an attribute of type “userCertificate” in the directory entry that has the DN that is the subject of the certificate (RFC 2828) Project: AUTO09
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X.509 an ITU-T Recommendation that defines a framework to provide and support data origin authentication and peer entity authentication services, including formats for X.509 public-key certificates, X.509 attribute certificates, and X.509 certificate revocation lists (The ISO equivalent is ISO 9498-4) (See X.500 Directory) (RFC 2828) Project: AUTO09
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X-dimension (bar code module width, mil size) - in bar code technology, the X-dimension (also known as bar code module width, mil size, cell size, or module width) is the width of a single bar code module in a specific bar code Project: AUTO14 NOTE 1: The X-dimension determines the bar code’s overall density; NOTE 2: This X-dimension is usually referred to in mm, µm or mil (thousandths of an inch). For example, a linear bar code with 0.005-inch X-dimension bar width is referred to as a 5-mil bar code (equal to a module size of 127 µm). For two-dimensional bar codes with an X-dimension of 10 mil, the cell size is 10 mil × 10 mil (or 254 µm × 254 µm)
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Y direction the horizontal direction perpendicular to specimen travel along a transportation system Project: AUTO02 NOTE: Specimens could move in the Y dimension away from a transport system to be placed onto an instrument for analysis. The sample probe would move in the Y dimension as it moves out from the instrument or specimen processing and handling device to a position directly over the specimen container.
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Z direction the vertical dimension of specimen travel Project: AUTO02 NOTE 1: Specimens could be lifted in the Z dimension off a transport system for transfer between locations; NOTE 2: The center line of a container should be controlled, so it is in the Z dimension; a specimen centering device would be referenced to the Z dimension; a sample probe would follow the Z dimension as it moves downward into a specimen container to aspirate serum, blood, etc., for analysis; NOTE 3: Rotation about the Z dimension may be used to locate and read the bar-code label on a specimen container or to assess the quality of a specimen in terms of turbidity, hemolysis, icterus, etc.
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zero adjustment of a measuring system adjustment of a measuring system so that it provides a null indication corresponding to a zero value of a quantity to be measured (JCGM 200:2008) Alternate Term: zero adjustment Project: ISO IEC Guide 99
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zero error datum measurement error where the specified measured quantity value is zero (JCGM 200:2012) Project: ISO IEC Guide 99 NOTE: Zero error should not be confused with absence of measurement error (JCGM 200:2012).
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zero error (of a measuring instrument) datum error for zero value of the measurand
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zone diameter diameter (in mm) of the zone of growth inhibition around a disk containing an antimicrobial agent in an agar diffusion test (ISO 20776-2) Project: ISO 20776-2
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zones regions on an error grid plot corresponding to different magnitudes of measurement error and associated with different levels of potential patient harm Project: EP27
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zoonotic a disease or parasite that primarily affects animals, but may be transmitted to humans Project: POCT10
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zoospore motile asexual spore that uses flagellum for locomotion Project: M54
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zygospore a mucoraceous spore formed by the union of two compatible but opposite mating types
Project: M54
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