- Measured portion of a whole having the same composition. general term referring to part of a solution, sample, mixture, etc.
- A part of a larger thing, especially a sample of somethi...
|allowable total error, tea|
An analytical quality requirement that sets a limit for both the imprecision (random error) and inaccuracy (systematic error) that are tolerable in a single measurement or single test result.
|analytical measurement range.|
|analysis of variance, anova|
A statistical technique by which the observed variance can be divided into components, such as within-run and between-run variance which make up the total variance observed for an analytical metho...
- The substance to be measured. clsi recommends using the term “measurand” “for a particular quantity subject to measurement.”
- A substance measured in the laboratory. a chemical for w...
|analytic process, system|
Refers to the part of the total testing process that involves measurement and analysis, as opposed to the pre-analytic part that deals with all the steps prior to performing the test and the post-...
Difference between the estimated value of a quantity and its true value. this difference (positive or negative) may be expressed either in the units in which the quantity is measured, or as a perc...
|analytical measurement range, amr|
Defined by cap (college of american pathologists) as the range of numeric results a method can produce without any special specimen pre-treatment, such as dilution, that is not part of the usual a...
|analytical quality assurance (aqa)|
Used with charts of operating specifications (opspecs charts) to indicate the level of assurance for detecting critical sized errors. for example, 90% aqa(se) means there will be at least a 90% ch...
|analytical quality requirement|
Used here to refer to a quality requirement in the form of an allowable total error (tea). often defined on the basis of proficiency testing criteria for acceptable performance, such as the clia r...
Generally defined by clia as an 8 hour to 24 hour interval during which control materials must be analyzed. according to clsi c24, a run is “an interval (i.e., a period of time or series of measur...
The ability of an analytical method to detect small quantities of the measured component. numerically characterized by determination of detection limit.
The ability of an analytical method to measure only the sought-for analyte or measurand. numerically characterized by determination of interferences and non-specific responses to other analytes or...
Refer to those properties of a method which determine whether the method can be implemented in the particular laboratory of interest, assuming the method will perform acceptably. characteristics s...
|assayed control material|
A control solution or control material for
Used here to represent the bias of a measurement procedure relative to a comparative method or a comparative group in proficiency testing.
|biological limit of detection, bld|
An older term that was commonly used to refer to an estimate of detection limit calculated from replicate measurements of a blank sample and replicate measurements of a low concentration sample. t...
The display of paired-data from a comparison of methods experiment by plotting the differences between the test and comparative results on the y-axis versus the average of the test and comparative...
“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 laboratory’s ...
|college of american pathologists.|
|centers for disease control|
cdc; centros de control y prevención de;
|certified reference material, crm|
“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 certifyi...
clinical laboratory improvement amendments of 1988;
|clinical laboratory improvement amendments of 1988|
|clinical quality requirement|
Used here for a quality requirement that states the medically important change in a test result or describes the gray zone or decision interval for interpreting a test result.
|clinical reportable range, crr|
Defined by cap (college of american pathologists) as the lowest and highest numeric results that can be reported after accounting for any specimen dilution or concentration that is used to extend ...
|clinical sensitivity, diagnostic sensitivity|
A measure of how frequently a test is positive when a particular disease is present. generally given as a percentage of individuals with a given disease who have a positive test result. ideally, a...
|clinical specificity, diagnostic specificity|
A measure of how frequently a test is negative in the absence of a particular disease. generally given as the percentage of individuals without a given disease who have a negative test result. ide...
|clinically significant, clinically significant difference|
Used in method validation to describe a difference or error that is larger than allowable for the clinical or medical use of a test. an important conclusion when judging the acceptability of a met...
clinical laboratory and standards institute, formerly national committee for clinical laboratory standards (nccls);
|clinical laboratory and standards institute, formerly national committee for clinical laboratory standards (nccls)|
|centers for medicare and medicaid services|
Центры служб "medicare" и "medicaid" cms; центры служб "medicare" и "medicaid"; центры служб;
|coefficient of variation, cv|
The relative standard deviation, i.e., the standard deviation expressed as a percentage of the mean [cv=100(s/x)]
|originally, commission for office laboratory accreditation|
|combined standard uncertainty|
Standard uncertainty of the result of a measurement when that result is obtained from the values of a number of other quantities, equal to the positive square root of a sum of terms, the terms bei...
|comparative method, comparative analytical method|
Used here to indicate the analytical method to which the test method (the one under study) is compared in the comparison of methods experiment. this term make no inference about the quality of the...
|comparison graph, comparison plot|
Used here to refer to the display of paired test results in which the test method values are plotted on the y-axis versus the comparison method values on the xaxis.
|comparison of methods experiment|
A method validation experiment in which a series of patient samples are analyzed both by the test method (the one under study) and a comparison method (an established method). the purpose is to as...
|confidence interval, confidence range|
The interval or range of values which will contain the population parameter with a specified probability.
|constant systematic error, ce|
An error that is always the same direction and magnitude even as the concentration of analyte changes.
- "a graphical method for evaluating whether a process is or is not in a `state of statistical control.` the determinations are made through comparison of the values of some statistical measure(...
|control material, control product|
A control solution that is available, often commercially, liquid or lyophilized, and packaged in aliquots that can be prepared and used individually.
|control measurements, control observations|
The analytical results obtained for control solutions or control materials (that are analyzed for purposes of quality control).
|control procedure, qc procedure|
The protocol and materials that are necessary for an analyst to assess whether the method is working properly and patient test results can be reported - that part of an analytical process that is ...
A decision criterion for interpreting control data and making a judgement on the control status of an analytical run. symbolized here by al, where a is the abbreviation for a particular statistic ...
|correlation coefficient, r|
A statistic that estimates the degree of association between two variables, such as the measurement result by a test method and the measurement result by a comparison method. a value of 1.000 indi...
|criteria for acceptability|
Clia`s term for the decision criteria applied to assess the validity of an analytical run. another name for qc procedure, with emphasis on definition of the decision criteria or control rules for ...
|critical random error, recrit|
The size of random error that causes a 5% maximum defect rate for the analytical process. calculated as (tea- biasmeas)/1.65smeas , where tea is the allowable total error, biasmeas is the inaccuracy, and smeas is the imprecision (standard deviation) of the measurement procedure.;
|, where tea is the allowable total error, biasmeas is the inaccuracy, and smeas is the imprecision (standard deviation) of the measurement procedure.|
critical random error, recrit; critical systematic error, secrit;
|critical systematic error, secrit|
The size of the systematic error that needs to be detected to maintain a defined quality requirement. calculated as [(tea - biasmeas)/smeas] - 1.65 , where tea is the allowable total error, biasmeas is the inaccuracy, and smeas is the imprecision (standard deviation) of the measurement procedure.;
A power function graph on which is imposed the critical-error that needs to be detected. facilitates the estimation and comparison of the probability for error detection by different qc procedures...
Churchill research range clinically reportable range; churchill research range;
|clinically reportable range|
|cumulative control limits|
Control limits calculated from estimates of the mean and standard deviation that represent a time period longer than a month. common practice is for laboratories to calculate monthly control stati...
|coefficient of variation (sd divided by mean times 100)|
|decision interval, dint|
Used here to represent the gray zone, or interval of uncertainty, in interpreting a test result. an example is the ncep (national cholesterol education program) guidelines that indicate a choleste...
|decision level for critical interpretation (xc)|
See medical decision level.
|definitive method, dm|
“an analytical method that has been subjected to thorough investigation and evaluation for sources of inaccuracy, including nonspecificity.” [clsi]
|degrees of freedom, df|
This is the number of independent comparisons that can be made among n observations. it may be thought of as the number of measurements in a series minus the number of restrictions on the series. ...
An alternate regression calculation that can be employed when ordinary linear regression may not be reliable. this technique takes into account the imprecision of both the test and comparative met...
|designated comparison method, dcm|
“a fully specified method, 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 de...
- General concept meaning “the smalled test value that can be distinguished from zero.” depending on how this is determined experimentally, there are different estimates that can be made. see li...
|difference graph, difference plot|
Used here to refer to the display of paired test results in which the differences between the test values and the comparison values are plotted on the y-axis versus the comparison values on the x-...
Set of operations having the objective of determining the value or characteristics of a property. [iso]
Quantity defining an interval about the result of a measurement that may be expected to encompass a large fraction of the distribution of values that could reasonably be attributed to the measuran...
See probability for false rejection.
food and drug administration; functional demonstration and acceptance; федеральная администрация по пищевым и лекарственным продуктам, сша; fda;
- Functional demonstration and acceptance
- Abbreviation for food and drug administration. organization responsible for, among other things, laser safety.
- Food and drug admin...
|food and drug administration|
|fda-cleared or approved test system|
A test system cleared or approved by the food and drug administration through the pre-market notification (510k) or pre-market approval (pma) process for in-vitro diagnostic use.
|frequency of errors, frequency of occurrence of analytical errors, f|
A performance characteristic of a measurement procedure that describes how frequently analytical errors are expected to occur. related to the stability of the measurement procedure.
A statistical test of significance in which the difference between two variances is tested. a variance is the square of a standard deviation. the f-test is often used to compare the imprecision of...
|functional sensitivity, fs|
This term is commonly used to refer to an estimate of detection limit that is calculated from replicate measurements of low concentration patient samples. by definition, fs is the lowest concentra...
|gaussian curve gaussian distribution normal curve normal distribution|
Refers to a symmetrical bell-shaped distribution whose shape is given by a specific equation (called the normal equation) in which the mean and standard deviation are variables. it is commonly ass...
|high complexity tests|
A clia category of tests that has the most demanding qc requirements. includes any tests developed by the laboratory, modified by the laboratory, or manufacturer`s tests that have been classified ...
“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.” [clsi] ifcc has recommende...
|inherent imprecision, inherent random error|
The standard deviation or coefficient of variation of the results in a set of replicate measurements obtained when the measurement procedure is operating under stable conditions.
The place at which a line on a graph intersects the axis. in regression analysis, this statistic refers specifically to the y-intercept, a.