Lably
Skip to content

Drug test

Technical analysis of a biological specimen

  • 26 min read
  • 6 chapters

Related on Lably

Through Urine, Hair and Blood

A drug test may also refer to a test that provides quantitative chemical analysis of an illegal drug, typically intended to help with responsible drug use.

Detection periods

The detection windows depend upon multiple factors: drug class, amount and frequency of use, metabolic rate, body mass, age, overall health, and urine pH. For ease of use, the detection times of metabolites have been incorporated into each parent drug. For example, heroin and cocaine can only be detected for a few hours after use, but their metabolites can be detected for several days in urine. The chart depicts the longer detection times of the metabolites. In the case of hair testing, the metabolites are permanently embedded into hair, and the detection time is determined by the length of the hair sample used in the analysis. The standard length of head hair used in the test is 1.5", which corresponds to about 3 months. Body/pubic hair grows slower, and the same 1.5" would result in a longer detection time.

Oral fluid or saliva testing results for the most part mimic that of blood. The only exceptions are THC (tetrahydrocannabinol) and benzodiazepines. Oral fluid will likely detect THC from ingestion up to a maximum period of 6–12 hours. This continues to cause difficulty in oral fluid detection of THC and benzodiazepines.

Breath air for the most part mimics blood tests as well. Due to the very low levels of substances in the breath air, liquid chromatography–mass spectrometry has to be used to analyze the sample according to a recent publication wherein 12 analytes were investigated.

Rapid oral fluid products are not approved for use in workplace drug testing programs and are not FDA cleared. Using rapid oral fluid drug tests in the workplace is prohibited in only:

The following chart gives approximate detection periods for each substance by test type.

Sign in to keep reading

5 more chapters are free with a Lably account.

More in Health