| 알파벳 | 내용 | | A | - absolute error : See error.
- acceptance criteria for specimens or samples : Procedures for acceptance or rejection of specimens or samples arriving at the analytical laboratory. Such procedures are focused on assessing the adequacy of the chain of custody [1].
- accreditation : Procedure by which an accreditation body formally recognizes that a laboratory or person is competent to carry out specific tasks.
- accreditation body : Independent science-based organization that has the authority to grant accreditation.
- accuracy : Ability to get the true result [2]. For quantitative tests the accuracy expresses the closeness of agreement between the true value and the value obtained by applying the test procedure a number of times. It is affected by systematic and random errors,
- action limit : See limit.
- aliquot : Portion of a liquid sample or solution.
- alternative hypothesis : See hypothesis testing.
- analysis : See test.
- analysis of variance (ANOVA) : Statistical technique that can be used to separate and estimate the different causes of variation [3].
- analyte or target analyte : Substance to be identified or measured [4] .
- surrogate analyte : Well-characterized substance that is taken as representative of the analyte [5].
- analftical batch : See barch.
- analytical method : See test.
- archive : Collection of documents and records purposefully stored for a defined period of time [6].
- arithmetic mean or average : Sum of the individual values in a set divided by the number of values [7].
- assay : Quantitative measurement of an analyte.
- assigned value : See value.
- average : See arithmetic mean.
| | B | -
batch or analytical batch : Group of one or more specimens or samples that are analysed under conditions approaching repeatability. Usually it should contain calibrators and quality control specimens or samples in addition to the samples to be analysed.
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best fit : See goodness-of-fit.
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bias : Difference between the expectation of the test result and an accepted reference value. There may be one or more systematic error components contributing to the bias [5].
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binomial distribution : See distribution.
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blank : specimen or sample not containing the analyte.
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blind specimen or sample : specimen or sample that is analysed by an operator who is unaware at the time of the analysis that the sample is for control purposes (based on [8]).
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blunder : Big mistake, especially one that seems to be the result of carelessness or stupidity [6]. See outlier. | | C | - calibration : Set of operations that establishes, under specified conditions, the relationship between values indicated by a measuring instrument or measuring system, or values represented by a material measure, and the corresponding known values of a measurand [9].
- calibration curve : Relationship between the signal response of the instrument and
various concentrations of analyte in a suitable solvent or matrix [7].
- calibration laboratory : laboratory that performs calibrations [91.
- calibration method : Defined technical procedure for performing a calibaration [9].
- calibrator : Pure analyte in a suitable solvent or matrix, used to prepare the calibration curve.
- certification : procedure by which a certifying body formally recognizes that a body, person or product complies with given specifications.
- certified reference material (CRM) : A reference material one or more of whose property values have been certified by a technical procedure, accompanied by or traceable to a certificate or other documentation that has been issued by a certifying body [9].
- certifying body : Independent science-based organization that has the competence to grant certifications.
- chain of custody : Procedures and documents that account for the integrity of a specimen or sample by tracking its handling and storage from its point of collection to its final disposition (adapted from [1]).
- chirality : Property of a molecule not superimposable on its mirror image. Due to asymmetry in their structures, chiral molecules can exist as different isomers and will have special optical and biological properties.
- chi-square distribution : See distribution.
- clerical error : See error.
- cochran test : See outlier
- coeffcient of variation or relative standard deviation : Measure used to compare the dispersion or variation in groups of measurements. It is the ratio of the standard deviation to the mean, multiplied by 100 to convert it to a percentage of the average[7], [10].
- collaborative studies or interlaboratory test comparisons : Organization, performance and evaluation of tests on the same or similar items or materials by two or more different laboratories in accordance with predetermined conditions. The main purpose is validation of analytical methods or establishment of reference methods [11].
- comparison-of-means test : See significance test.
concentration : Amount of a substance, expressed in mass or molar units, in a unit volume of fluid.
- confidence coefficient : See confidence level.
- confidence interval : Range of value that contains the true value at a given level of probability. This level of probability is called the confidence level.
- confidence level or confidence coefficient : Measure of probability, α, associated with a confidence interval, expressing the probability of the truth of a statement that the interval will include the parameter value [12].
- confidence limits : The extreme values or end values in a confidence interval. See limit.
- confirmatory test : Second test by an alternative chemical method for unambiguous identification of a drug or metabolite (adapted from [2]).
- consensus value : See value.
- contractor : Organization that provides a service under contractual conditions. It should be ensured that the contractor provides services in line with specified criteria of competence.
- control chart : plot of test results with respect to time or sequence of measurements, with limits drawn within which results are expected to lie when the analytical scheme is in a state of statistical control [5].
- cusum chart : In a cusum chart each result is compared with a reference, usually the assigned or target value. The differences from the reference are then accumulated, respecting the sign, to give a cumulative sum of differences from the standard. The cusum chart has the advantage of identifying small persistent changes in the analytical scheme faster than the shewhart chart [7].
- Shewhart chart : chart where the variable of interest is plotted against batch or time. The observed values are compared with the expected or true value. Lines corresponding to the mean value obtained from repficate analysis of reference material and warning and action limits are inserted to provide objective criteria for the interpretation of the chart [5],
- control limit : see limit.
controls : specimens or samples used to determine the validity of the calibration, that is, the linearity and stability of a quantitative test or determination over time. Controls are either prepared from the reference material (separately from the calibrators, that is, weighed or measured separately), purchased, or obtained from a pool of previously analysed specimens or samples. where possible, controls should be matrix-matched to specimens or samples and calibrators [1].
- positive control : Control that contains the analyte at a concentration above a specified limit.
- negative control : Control that contains the analyte at a concentration below a specified limit. Usually a drug-free specimen or sample (blank) is used as a negative control.
- corrective action : Action taken to eliminate the causes of an existing deviation, defect or other undesirable situation in order to prevent recurrence.
- correlation coefficient : Number showing the degree to which two variables are related. Correlation coefficients range from 0 (no correlation) to -1 or +1 (perfect correlation).
- cross-reacting substance : In immunoassays, a substance that reacts with antiserum produced for the target analyte [2].
- cusum chart : See control chart.
- cut-off concentration : Concentration of a drug in a specimen or sample used to determine whether the specimen or sample is considered positive or negative [13]. In some circumstances it is recommended that the cut-off concentration should be set equal to the limit of detection. See threshold.
| | D | - degrees of freedom : Number of independent comparisons that can be made between the members of a sample [12].
- detection limit : See limit.
- deviation : Departure from what is considered normal [6]. See standard deviation.
- discrimination : Ability to recognize and understand the differences between two things [6].
- distribution : A ranking, from lowest to highest, of the values of a variable and the resulting pattern of measures or scores when they are plotted on a graph (adapted from [10]). A frequency distribution, for example, gives the possible values of a parameter versus the number of times each value occurred in the sample or population. In many instances it refers to the spread of the individual values of a sample or population around the mean.
- binomial distribution : Based on the idea that if only one of two possible outcomes can occur on any one occasion, then the theoretical distribution of the different combinations of outcomes that could occur can be worked out if the number of occasions is known. One characteristic of this distribution is that it consists of a limited or finite number of events, n. When n becomes very large, tending to infinity, the binomial distribution becomes the normal distribution
- chi-square distribution : This distribution may be considered as that of the sum of squares of v independent normal variates in standard form. The parameter v is known as the number of degrees of freedom [12].
- F-distribution : Theoretical distribution used to study population variance. It is the distribution of the ratio of two independent variables each of which has been divided by its degrees of freedom [10].
- normal distribution : Purely theoretical continuous probability distribution in which the horizontal axis represents all possible values of a variable and the vertical axis represents the possible of those values occurring. The scores on the variable are clustered around the mean in a symmetrical, unimodal pattern known as the bell-shaped (normal) curve. In a normal distribution, the mean, median and mode are all the same [10]. The normal distribution is obtained when the number of events in the binomial distribution n, becomes very large, tending to infinity.
probability distribution : Distribution giving the probability of a value of x as a function of x or, more generally, the probability of joint occurrence of a set of variates x1,….,xp as a function of those quantities [12].
- t-distribution : Theoretical probability distribution used in hypothesis testing. Like the normal distribution, the t-distribution is unimodal, symmetrical and bell-shaped [10].
- theoretical probability distribution : Number of times it can be expected to get a particular number of successes in a large number of trials [10]. Important theoretical probability distributions are the normal, t-, chi-square and F-distributions .
- z-distribution : Normal distribution in which the scores are the z-scores[10].
- distribution function : The distribution function F(x) of a variate x is the total frequency of members with variate values less than or equal to x. As a general rule, the total frequency is taken to be unity, in which case the distribution function is the proportion of members bearing values less than or equal to x [12].
- dixon test : See outlier.
- double blind procedure : Means of reducing bias in an experiment. In the clinical context, for example, such a procedure ensures that both those who administer a treatment and those who receive it do not know (are blind to) which subjects are in the control group and which are in the experimental group, that is, who is and is not receiving the treatment (adapted from [10]).
- duplicate samples or specimens : Two aliquots of a sample or specimen analysed at the same time.
- dynamic range : Range over which a relationship exists between analyte concentration and assay response [14].
| | E | - Error : Something done that is considered to be incorrect or wrong [6].
- absolute error : Difference between the analytical result and the true value[15].
- clerical error : Mistake made during routine jobs in an office or laboratory, e.g. a transcription error, a specimen misidentification or a fling error.
- maximum tolerable error : Extreme values of an error permitted by specifications, regulations etc. for a given determination. [16].
- random error : Component of the total error of a measurement that varies in an unpredictable way. This causes the individual results to fall on both sides of the average value [3], [17].
- relative error : Absolute error of a measurement divided by the assigned value of the analyte [16]. See coefficient of variation and relative ,standard deviation.
- systematic error : Component of the total error of a measurement that varies in a constant way. This causes all the results to be in error in the same sense [3], [16].
- total error : Sum of random and systematic errors.
- type I error : Error made by wrongly rejecting a true null hypothesis[10]. If the null hypothesis is that the sample should be negative, a type I error will generate a false positive result.
- type ll error : Error made by wrongly accepting a false null hypothesis [10]. If the null hypothesis is that the sample should be negative, a type ll error will generate a false negative result.
- estimate value : See value.
- evaluation : Systematic examination of the extent to which a product, process or service fulfiles specified requirements [11].
- expert witness : Knowledgeable person, for example, a forensic scientist, familiar with the testing and the interpretation of test results and able to give an expert opinion based on scientific fact or evidence, e.g. in court or at a hearing (adapted from [18]).
- expiration date : Date after which the specified characteristics of a reagent, solution, specimen, control etc. can no longer be guaranteed.
| | F | - false negative : Test result that states that no drug or metabolite is present when, in fact, such a drug or metabolite is present in an amount greater than a threshold or designated cut-off concentration (adapted from [19]).
- false positive : Test result that states that a drug or metabolite is present when, in fact, it is not present or is present in an amount less than a threshold or designated cut-off concentration (adapted from [19]).
- F-distribution : See distribution.
- F-test : See significance test.
| | G | - geometric mean : See mean.
- good laboratory practices (GLP) : Organizational process and conditions under which laboratory studies are planned, performed, monitored, recorded and reported. Includes a system of protocols (standard operating procedures) recommended to be followed so as to avoid the production of unreliable and erroneous data (adapted from [20] and [21]).
- goodness-of-fit : How well a model, a theoretical distribution or an equation matches actual data [10].
- Grubbs test : See outlier.
| | H | - harmonization : Bringing about agreement on terminology, concepts etc. so that different entities can interact based on the same terms of reference.
- hypothesis test : See significance test.
- hypothesis testing or significance testing : Process of assessing the statistical significance of a finding. It involves comparing empirically observed sample findings with theoretically expected findings, expected if the null hypothesis is true (see significance test). This comparison allows one to compute the probability that the observed outcomes could have been due to chance alone [22]. See non-parametric test.
- alternative hypothesis : Hypothesis that must be accepted if the null hypothesis is rejected [22].
- null hypothesis (H0 ) : Any hypothesis to be tested. The term null implies that there is no difference between the observed and known values other than that which can be attributed to random variation (adapted from [3) and [22]].
| | I | - Imprecision : See precision.
- independent test result : result obtained in a manner not influenced by any previous results on the same or similar material [5].
- influence quantity : Quantity, e.g. an environmental condition, that is not the subject of measurement but that influences the result (adapted from [16]).
- in-house reference material : See screening test.
- initial test : See screening test.
- instrument linearity : Straight-line relationship between concentrations of analyte and instrument response, in which a change in concentration causes a proportional change in response [19].
- interfering substance : Substance other than the analyte that gives a similar analytical response or alters the analytical result [2].
- interlaboratory test comparisons : See collaborative studies.
- internal standard : Addition of a fixed amount of a known substance that is not already present as a constituent of the specimen or sample in order to identify or quantify other components [18]. The physico-chemical characteristics of the internal standard should be as close as possible to those of the analyte.
- Interpretation : Explanation of what analytical results mean based on chemical, pharmacological, toxicological and statistical principles.
- intralaboratory test comparisons : Organization, performance and evaluation of tests on the same or similar items or materials within the same or laboratory in accordance with predetermined conditions [11].
| | L | - laboratory : Facilities where analyses are performed by qualified personnel using adequate equipment.
- laboratory Information Management System : See LIMS.
- least-squares : Statistical method of determining a regression equation, that is, the equation that best represents the relationship among the variables [10].
- level of significance : Probability that a result would be produced by chance alone, i.e. the probability of incorrectly rejecting the null hypothesis. It is, therefore, the probability of making a type 1 error.
- limit: Prescribed or specified maximum or minimum amount, quantity or number[23].
- action limit : Corresponds to a ±3 standard deviation front the mean. If an observed value falls outside the action limit, the cause must be identified immediately and remedial action taken.
- confidence limit : The limits of the confidence interval.
- control limit : The limits, on a control chart, that are used as criteria for action or for judging whether a set of data does or does not indicate lack of statistical control.
- detection limit : Smallest measured content from which it is possible to deduce the presence of the analyte with reasonable statistical certainty [17], [24].
- quantitation limit : The smallest measured content from which it is possible to quantitate the analyte with an acceptable level of accuracy and precision.
- warning limit : Corresponds to a ±2 standard deviation from the mean. Even if the method is under statistical control, approximately 5 per cent of results may be expected to fall outside the warning limits.
- LIMS (Laboratory Information Management System) : Software package for collating, calculating, controlling and disseminating analytical data. It can perform a variety of functions, from specimen or sample registration and tracking to processing captured data, quality control, financial control and report generation [25].
- linear regression : Method of describing the relationship between two or more variables by calculating a best-fitting straight line or graph [10].
- logbook : Book that records laboratory activities, e.g. instrumentation, maintenance of instrumentation, sample preparation and reagents.
| | M | - maintenance : Activity of keeping something such as facilities, machines or instrumentation in good condition by regularly checking it and doing necessary repairs [6].
- matrix : Material that contains the analyte, e.g. urine or blood.
- maximum tolerable error : see error.
- mean : When not otherwise specified, refers to arithmetic mean [10].
- geometric mean : The nth root of the product of n individual values.
- median : Middle value of a ranked set of data [7].
- metabolite : Compound produced in the body as a result of biochemical processes.
- method : Detailed (defined) procedure for performing an analysis. See test procedure.
- method traceability : Property of a method whose measurements give results that can be related, with a given uncertainty, to a particular reference, usually a national or International standard, through an unbroken chain of comparisons (adapted from[5]).
- mode : In statistics, the value or values occurring most frequently in a set of data[7].
| | N | - negative : Indicates that the analyte is absent or below a designated cut-off concentration. "Not detected" Is sometimes used as a synonym for negative, although this Is not recommended.
- negative control : See control.
- none detected : Indicates the absence of an analyte within the specifications of the test(s) performed.
- non-parametric test : Statistical method that makes no assumptions about the distribution of the population from which the sample data are taken (adapted from [3]).
- one-tail test : Hypothesis test stated so that the chances of making a type 1 error are located entirely in one tail of a probability distribution, e.g. it is applicable if we wish to test only whether method A is more precise than method B and not whether method B is more precise than method A (adapted from [10]).
- two-tail test : Statistical test in which the critical region (the region of rejection of the null hypothesis) is divided into two areas at the tails of the sampling distribution, e.g. it is applicable if we wish to test whether methods A and B differ in their precision (adapted from [10]).
- normal distribution : See distribution.
- not detected : The use of this term as a synonym for negative is not recommended.
- null hypothesis : See hypothesis testing.
| | O | - one-point calibration : Simplified calibration procedure using a single calibrator and a blank.
- one tail test : See non-parametric test.
- organization : Company, corporation or institute (or part thereof, e.g. a laboratory), private or public, that has its own functions and administration. Some of the international organizations dealing with quality assurance are the International Association of Forensic Toxicologists (TIAFT), the International Federation of Clinical Chemistry (IFCC), the International Olympic Committee (lOC), the International Organization for Standardization (ISO), the International Programme on Chemical Safety (IPCS), the International Union of Pure and Applied Chemistry (lUPAC), and the Organization for Economic Co-operation and Development (OECD).
- outlier : Result that appears to differ unreasonably from the population of the other results. Tests for outliers include the following:
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