Terminology

Terminology in drug testing is not standardized. New terms are being used to help describe important phenomena. The following is a review of terms that could be helpful:

Analyte: The substance (drug or molecule) being tested for (i.e. EtG, EtS, alcohol, benzoylecognine, etc)

Matrix (pl matrices): The tissue, body fluid, or substance being tested. Any tissue or substance can be tested but the most common matrices are urine, hair, blood, saliva, and fingernails.

Innocent positive:  Implies a positive test not the result of intentional use of the analyte (incidental or accidental exposure)

False positive: 1. Refers to a test that reports positive when the substance was not actually present. or 2. A positive test that is an innocent positive (ie the person didn't actually use knowingly use the substance.)
 
Cutoff: 1. The number which if exceeded in the sample tested causes a positive report to be made. (Determined by lab based on limits of equipment, test linearity, government regulations, or agreement with client. or 2. The number which if exceeded in the sample tested indicates that the presence of the analyte was likely from intentional use and not from incidental exposure. (Sometimes called the secondary cutoff. Determined after testing large populations with many ages, sexes, illnesses, etc, utilizing different sources of incidental exposure, to determine if a cutoff can distiquish between incidental exposure and actual use.) (Note: This study has not been performed for new alcohol markers - EtG and EtS therefore the secondary cutoff is not known.)

Incidental Exposure: Environmental or other exposure to an analyte not typically thought of as a method of use of the drug (e.g. hemp oil contains marijuana, poppy seeds contain opium, mouthwash contains ethanol - none of the products are typically used to "get high" yet they contain the analyte and can "accidentally" cause a positive test).
   

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