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Standards and Guidelines - Forensic Science Communications - January 2005


January 2005 - Volume 7 - Number 1

Standards and Guidelines

Scientific Working Group for the Analysis of Seized Drugs Glossary

Scientific Working Group for the Analysis of Seized Drugs (SWGDRUG)

Revised November 2003

The following definitions were developed and adopted by the Scientific Working Group for the Analysis of Seized Drugs core committee from a variety of sources including the United Nations International Drug Control Programme's Glossary of Terms for Quality Assurance and Good Laboratory Practices, United Nations, 1995.

Accreditation is the procedure by which an accreditation body formally recognizes that a laboratory or person is competent to carry out specific tasks.

Accreditation body is an independent science-based organization that has the authority to grant accreditation.

Accuracy is composed of trueness and precision.

Analysis is the technical operation to determine one or more characteristics of, or to evaluate the performance of, a given product, material, equipment, physical phenomenon, process, or service according to a specified procedure.

Analyst is a designated person who

  • Independently has access to unsealed evidence in order to remove samples from the evidence for examination.

  • Examines and analyses seized drugs or related materials or directs such examinations to be done.

  • As a consequence of such examinations, signs reports for court or other purposes.

Audit is a review conducted to compare the various aspects of the laboratory's performance with a standard for that performance.

Blank is a specimen or sample not containing the analyte.

Calibration is a 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.

Certified reference material is 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.

Certifying body is an independent science-based organization that has the competence to grant certification.

Chain of custody are procedures and documents that account for the integrity of a sample by tracking its handling and storage from the point of collection to final disposition.

Control sample is a standard of comparison for verifying or checking the findings of an experiment.

Controls are 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 analyzed samples. When possible, controls should be matrix-matched to samples and calibrators.

Correlated techniques are those that have the same fundamental mechanism of characterization. For example, this would prevent the choice of two gas chromatographic tests both based on a partition mechanism (e.g., methylsiloxane and phenylmethylsiloxane) or two thin layer chromatographic systems both based on an adsorption mechanism.

Deficiency of analysis is any erroneous analytical result or interpretation or any unapproved deviation from an established policy or procedure in an analysis.

False positive is a test result that states a drug is present when, in fact, such a drug is not present in an amount less than a threshold or designated cut-off concentration.

Health and safety manager is a designated person who is responsible for maintaining the laboratory's health and safety program (including an annual review of the program) and who monitors compliance with the program.

Independent test result is a result obtained in a manner not influenced by any previous results on the same or similar material.

Laboratory is a facility where analyses are performed by qualified personnel using adequate equipment.

Limit of detection is the smallest measured content from which it is possible to deduce the presence of the analyte with reasonable statistical certainty.

Limit of quantitation is the lowest concentration of analyte that can be determined with an acceptable level of precision and trueness.

Linearity defines the ability of the method to obtain test results proportional to the concentration of the analyte.

Method is a detailed, defined procedure for performing an analysis. See Procedure

Procedure is a specified, documented way to perform an activity.

Proficiency testing is the ongoing process in which a series of proficiency samples, the characteristics of which are not known to the participants, are sent to laboratories on a regular basis. Each laboratory is tested for its accuracy in identifying the presence (or concentration) of the drug using its usual procedures.

Qualitative analysis is a test that determines the presence or absence of specific drugs in the sample.

Qualitative test See Qualitative analysis

Quality assurance is a system of activities whose purpose is to provide, to the producer or user of a product or a service, the assurance that it meets defined standards of quality with a stated level of confidence.

Quality assurance manager is a designated person who is responsible for maintaining the quality management system and who monitors compliance with the program.

Quality management is that aspect of the overall management function that determines and implements the quality policy.

Quality manual is a document stating the general quality policies, procedures, and practices of an organization.

Quantitative analysis is a procedure to determine the quantity of drug present in a sample.

Quantitative test See Quantitative analysis

Range is a set of concentrations of the analyte in which the error of a method is intended to lie within specified limits.

Reference material is a material or substance, one or more properties of which are sufficiently well established to be used for calibrating an apparatus, assessing a measurement method, or assigning values to materials.

Repeatability is the closeness of the agreement between the results of successive measurements of the same measurand carried out under the same conditions of measurement.

Report is a document containing a formal statement of results of tests carried out by a laboratory.

Representative sample is statistically, a sample that is similar to the population from which it was drawn. When a sample is representative, it can be used to make inferences about the population. The most effective way to get a representative sample is to use random methods to draw it. Analytically, it is a sample that is a portion of the original material selected in such a way that is possible to relate the analytical results obtained from it to the properties of the original material.

Reproducibility is the closeness of agreement between the results of successive measurements of the same analyte in identical material made by the same method under different conditions (e.g., different operators and different laboratories and considerably separated in time).

The robustness of an analytical procedure is a measure of its capacity to remain unaffected by small but deliberate variations in method parameters and provides an indication of its reliability during normal usage.

Sample is a portion of the whole material to be tested. Statistically, it is a set of data obtained from a population.

Sampling is analytically the whole set of operations needed to obtain a sample, including planning, collecting, recording, labeling, sealing, and shipping. Statistically, it is the process of determining properties of the whole population by collecting and analyzing data from a representative segment of it.

Selectivity is the extent to which a method can determine particular analyte(s) in a mixture without interference from the other components in the mixture. A method that is perfectly selective for an analyte or group of analytes is said to be specific.

Specificity See Selectivity

Standard operating procedures are written documents that detail the methods of an operation, analysis, or action whose techniques and procedures are thoroughly prescribed and that is accepted as the method for performing certain routine or repetitive tasks.

Supervisory chemist is a designated person who has the overall responsibility and authority for the technical operations of the drug analysis section.

Technician or assistant analyst is a person who analyses evidence but does not issue reports for court purposes.

Technical support personnel are people who perform basic laboratory duties but do not analyze evidence.

Test See Analysis

Traceability is the property of a result of a measurement whereby it can be related to appropriate standards, generally international or national standards, through an unbroken chain of comparisons.

Traceable is the ability to trace the history, application, or location of an entity by means of recorded identification. See also Chain of custody

Trueness is the closeness of agreement between the average value obtained from a large set of test results and an accepted reference value.

Uncertainty is a parameter associated with the result of a measurement that characterizes the dispersion of the values that could reasonably be attributed to the measurand.

Validation is confirmation by examination and provision of objective evidence that the particular requirements for a specific intended use are fulfilled.

Verification is confirmation by examination and provision of objective evidence that specified requirements have been fulfilled. (A method works in any laboratory as well as in the laboratory where it was validated.)