Analysts use a number of terms relating to the chemistry, analysis and reporting of controlled substances. The glossary terms below are from the Scientific Working Group for the Analysis of Seized Drugs (SWGDRUG).
Accuracy - Closeness of agreement between a test result or measurement result and the true value.
Analyst - A designated person who examines and analyzes seized drugs or related materials, or directs such examinations to be done; independently has access to unsealed evidence in order to remove samples from the evidentiary material for examination and as a consequence of such examinations, signs reports for court or other purposes.
Analyte - The component of a system to be analyzed.
Audit - Systematic, independent and documented process for obtaining audit evidence and evaluating it objectively to determine the extent to which audit criteria are fulfilled.
Bias - The difference between the expectation of the test results and an accepted reference value.
Blank - Specimen or sample not containing the analyte or other interfering substances.
Byproduct - A secondary or incidental product of a manufacturing process.
Calibration - The act of checking or adjusting (by comparison with a standard) the accuracy of a measuring instrument. 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.
Capacity - The amount of finished product that could be produced, either in one batch or over a defined period of time, and given a set list of variables.
Catalyst - A substance whose presence initiates or changes the rate of a chemical reaction, but does not itself enter into the reaction.
Certified reference material (CRM) - Reference material characterized by a metrologically valid procedure for one or more specified properties, accompanied by a certificate that provides the value of the specified property, its associated uncertainty, and a statement of metrological traceability.
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.
Clandestine - Secret and concealed, often for illicit reasons
Control - Material of established origin that is used to evaluate the performance of a test or comparison.
Detection limit - The lowest concentration of analyte in a sample that can be detected, but not necessarily quantitated under the stated conditions of the test.
False negative - Test result that states that an analyte is absent, when, in fact, it is present above the established limit of detection for the analyte in question.
False positive - Test result that states that an analyte is present, when, in fact, it is not present or, is present in an amount less than a threshold or designated cut-off concentration.
Finished product - A manufactured product ready for use.
Intermediate - Substance that is manufactured for and consumed in or used for chemical processing to be transformed into another substance.
Limit of quantitation - The lowest concentration of an analyte that can be determined with acceptable precision (repeatability) and accuracy under the stated conditions of the test.
Linearity - Defines the ability of the method to obtain test results proportional to the concentration of analyte.
Pharmaceutical identifiers - Physical characteristics of tablets, capsules or packaging indicating the identity, manufacturer, or quantity of substances present.
Population - The totality of items or units of material under consideration.
Precision - Closeness of agreement between independent test/measurement results obtained under stipulated conditions.
Precursor - A chemical that is transformed into another compound, as in the course of a chemical reaction, and therefore precedes that compound in the synthetic pathway.
Procedure - Specified way to carry out an activity or process.
Proficiency testing - Ongoing process in which a series of proficiency specimens or 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. An accreditation body may specify participation in a particular proficiency testing scheme as a requirement of accreditation.
Qualitative analysis - Analysis in which substances are identified or classified on the basis of their chemical or physical properties, such as chemical reactivity, solubility, molecular weight, melting point, radiative properties (emission, absorption), mass spectra, nuclear half-life, etc. See also A.2.29 quantitative analysis.
Quantitative analysis - Analyses in which the amount or concentration of an analyte may be determined (estimated) and expressed as a numerical value in appropriate units. Qualitative analysis may take place without quantitative analysis, but quantitative analysis requires the identification (qualification) of the analytes for which numerical estimates are given.
Random sample - The sample so selected that any portion of the population has an equal (or known) chance of being chosen. Haphazard or arbitrary choice of units is generally insufficient to guarantee randomness.
Reagent - A chemical used to react with another chemical, often to confirm or deny the presence of the second chemical.
Repeatability (of results of measurements) - Closeness of the agreement between the results of successive measurements of the same measurand carried out subject to all of the following conditions: the same measurement procedure; the same observer; the same measuring instrument, used under the same conditions; the same location; repetition over a short period of time.
Reproducibility (of results of measurements) - Closeness of the agreement between the results of measurements of the same measurand, where the measurements are carried out under changed conditions such as: principle or method of measurement; observer; measuring instrument; location; conditions of use; time.
Sample - Subset of a population made up of one or more sampling units.
Sampling - Act of drawing or constituting a sample.
Sampling plan - A specific plan which states the sample size(s) to be used and the associated criteria for accepting the lot.
Sampling procedure - Operational requirements and/or instructions relating to the use of a particular sampling plan; i.e., the planned method of selection, withdrawal and preparation of sample(s) from a lot to yield knowledge of the characteristic(s) of the lot.
Sampling scheme - A combination of sampling plans with rules for changing from one plan to another.
Traceability - Ability to trace the history, application or location of that which is under consideration.
Trueness - Closeness of agreement between the expectation of a test result or a measurement result and a true value.
Validation - Confirmation, through the provision of objective evidence, that the requirements for a specific intended use or application have been fulfilled.
Verification - Confirmation, through the provision of objective evidence, that specified requirements have been fulfilled.