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 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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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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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 taking in or reception by physicochemical action Project: NRSCL8
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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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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 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 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 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 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 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 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, 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 (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 (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 (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 closeness of agreement between a test result and the accepted reference value (ISO 5725-1) Project: C44, C37, H44, ISO 15198, GP40, AUTO08, EP21, EP17, 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.”
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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 the ability of a microbial identification system to correctly identify the organism being tested Project: M50
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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 Section 6.5 of CLSI document 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 a process by which a substance is bound at the surface of a material (adsorbent). See also absorption Project: NRSCL8
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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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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 the force of attraction between molecules Project: I/LA30
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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 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 or calculations applied to test data that generate an interpretable or reportable result Project: MM17, I/LA28
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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 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 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 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 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 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 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 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 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 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 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 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 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 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 analytical quality goal that sets a limit 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
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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 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 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 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 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 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 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 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, 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 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 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 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, 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 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, MM23, 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 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 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 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 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 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 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, MM23, 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 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: GP41, PRE02
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anion exchange 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: GP41, 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 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 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 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 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 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 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 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 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 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 - 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 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 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 not rejecting the null hypothesis when it is false Alternate Term: type II error Project: EP07 NOTE: See power.
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beta error probability of falsely rejecting the alternative hypothesis when it is true Project: EP31
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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 an accepted reference 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 may 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 EP35, bias refers to the estimated bias at specific concentrations from a measurement procedure equivalence study; NOTE 8: In 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 (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, 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 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 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 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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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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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, animals, or their environment Project: QMS04
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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 (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 specific analyte (ie, 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 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 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 (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 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 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 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 (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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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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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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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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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, 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/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, 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 (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 minimal inhibitory concentration or zone diameter value used to categorize an organism as susceptible, susceptible-dose dependent, intermediate, resistant, or nonsusceptible Project: 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 outcome.
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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 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 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 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 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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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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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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CA membrane a reverse osmosis membrane constructed of cellulose diacetate/triacetate Project: GP40
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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, 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, correctthe quantity value and measurement uncertainty attributed to one of the measurement standards (JCGM 200:2012); NOTE 5: 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, EP32
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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 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 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 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 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 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 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 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 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 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 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 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-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 exchange 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 samples that are smeared across a glass microscope slide for subsequent staining and microscopic examination Project: MM23 NOTE: Cell cytology samples may also 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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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 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 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 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 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, 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 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 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 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 blood cells; used as a measure of specific antigen, antibody, or immune complex concentration Project: DI01
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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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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 for quantitative tests, an assessment of the amount of substance or analyte present or measured in a sample
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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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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 (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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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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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 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 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 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 cell-free tumor nucleic acid free tumor DNA circulating in plasma of patients with cancer Project: MM23 NOTE: The origin may 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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circulating tumor cell cell that has detached from a primary tumor and circulates in the bloodstream Project: MM23 NOTE: These cells may constitute seeds for subsequent growth of additional tumors (metastasis) in different tissues.
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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
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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 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, 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 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 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 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.
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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 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 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 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 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-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 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 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 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 using the individual standard measurement uncertainties associated with the input quantities in a measurement model Alternate Term: combined standard uncertainty Project: C51, EP32 NOTE 1: The symbol for a combined standard measurement uncertainty of the quantity y is uy or u(y); NOTE 2: See combined standard uncertainty.
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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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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, 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) 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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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 (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 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, EP21, 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 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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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 information that is essential 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 mutations 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 mutation and are most likely to respond favorably to specific immunotherapy agents.
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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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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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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 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 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 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 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 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 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 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 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 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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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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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, 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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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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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 based on screening test results Alternate Term: diagnostic test Project: NBS03, NBS08, NBS09, NBS05, NBS02, 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 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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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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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 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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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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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 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 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 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 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 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 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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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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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 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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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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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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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 Project: EP35 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 (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 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 (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 to monitor the status of an analysis to maintain its performance within desired limits Project: MM10, POCT04
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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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 (verb) to make a reproduction of an original Project: QMS26
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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 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 is not used for medical decision-making in patients who provide the samples Project: MM23
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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 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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corrosive a substance that can cause damage to human skin at the site of contact Project: QMS04
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corrosive having the quality of corroding or eating away; erosive (RHUD1.7CD)
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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: A coverage factor is usually symbolized k (JCGM 200:2012).
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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 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 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 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 the set of shared attitudes, values, goals, and practices that characterizes an institution or organization Project: QMS16
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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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culture medium a substance or preparation used for the cultivation and growth of microorganisms Project: M47
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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 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 all components of a health care organization where the in vitro diagnostic device is installed Project: AUTO09
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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 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 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 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 (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 (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 (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 (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 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 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 point See decision level Alternate Term: decision level; decision threshold; cutoff level Project: EP24
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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 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 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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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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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 (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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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 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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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 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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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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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 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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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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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 of an analytical method to detect small quantities of the component (IFCC-1978-QC Terminology)
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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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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 EP35 or the main text of 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 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 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 a determining agent or factor Project: NRSCL8
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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 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 or communication connection between a device and an access point Alternate Term: DAP Project: POCT02
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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 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 ability of a test system to obtain the correct result, including both sensitivity and specificity Project: MM03, MM22
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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 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 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 proportion of patients 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 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 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 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 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 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 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 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 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 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 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 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 See patient specimen Alternate Term: patient specimen; clinical specimen Project: M29
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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 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 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 agent capable of disinfecting inanimate surfaces (eg, work surfaces or medical devices) (modified from ISO 15190) Project: M29, POCT13 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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disinfectant a substance used to reduce the concentration of bacteria, fungi, or viruses on a surface Project: M47
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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 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: GP41, 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 utilizes 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 fraction of an operational cycle for which signals can be measured Project: C64
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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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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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dwell time the amount of time a mass analyzer monitors ions of a particular m/z Project: NBS04
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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 relationship between the result achieved and the resources used (ISO 9000) Project: QMS14, QMS12
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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 (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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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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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 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 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 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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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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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 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 (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 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 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 (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 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/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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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 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 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 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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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 (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 (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 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 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 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 the articles or implements used or needed for a specific purpose or activity Project: M29
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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 the condition of being equal or equivalent in value, worth, function, mean, etc. Project: EP35 NOTE: For the purpose of 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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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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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 (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 (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 (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, MM24 NOTE 1: The concept of “measurement error” can be used both a) 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 which case, the measurement error is known, and b) if a measurand is supposed to be represented by a unique true quantity value or a set of true quantity values of negligible range, in which 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 (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 (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 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 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 the determination of the performance characteristics of a new or modified measurement procedure Project: EP25
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establish define, document (in writing or electronically), and implement Project: GP26, QMS01 Source: Quality Glossary
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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 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 determines or supports the accountability, effectiveness, and efficiency of an activity or program Project: QMS16, QMS14, QMS03
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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 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 (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 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 document 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 document 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 EP35, examinations are also called measurement procedures; NOTE 8: In 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). (JCGM 2012)
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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, 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 Project: MM23 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 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 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 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 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 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 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 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) 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 which prevents their general circulation (ISO 15190) Alternate Term: fume hood Project: ISO 15190
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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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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 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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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 as a subtype of pleural fluid, due to inflammation and characterized by high protein and presence of cells
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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 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 negative an observation for which no event alarm occurs, although there is a relevant symptomatic event Project: MM19
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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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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, 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 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 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 standard data file standard for the output files generated by cytometry instruments Project: H62
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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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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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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 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 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 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 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 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 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 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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fluorometer an instrument that measures the intensity of fluorescence Project: DI01
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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, 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, 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 describes 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 the frequencies or their relative frequencies 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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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 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 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 (IVD) 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 standardization in which the calibration of two or more IVD 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 IVD medical devices (ISO 21151)
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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 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 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 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 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 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 care provider health care professional, usually in the community, who provides basic health care for an individual Project: NBS03
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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 1) the clumping of red blood cells; 2) agglutination reactions using erythrocytes. (Cf. DI1)
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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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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: GP41, 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 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 breaking down of red blood cells with liberation of hemoglobin (RHUD-1.7CD) Project: C37
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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 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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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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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 significant blood depletion as a result of volume removed for diagnostic blood sampling Project: GP42, GP41, 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 ligand-binding assay that uses a specific antigen or antibody capable of binding to the analyte Project: C45, NRSCL8
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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 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 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 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 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 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 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 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 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 the act of accomplishing some aim, executing some order, or carrying into effect Project: I/LA33
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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 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 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 the presence of random error, variability, or inconsistency Project: POCT04
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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, 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 (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 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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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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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: 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 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 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 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 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 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 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, 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 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 reagen |