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Drug Testing Methods

How Many Different Types Are Used? What Is the Accuracy for the Different Types?


There are several different types of tests given to detect drug use. If current drug use is suspected, a blood or breath test often is administered. If previous drug use is suspected, a urine or hair test may be used. These tests look for chemical metabolites, or traces, that the drug leaves behind after it is eliminated from the body.

While hair tests are usually used as a secondary test or in cases of criminal offenses, there is a growing number of schools and businesses that are using hair tests instead of urine tests. If the method is hair testing, it is much more likely that a nonuser will test positive, especially if the test subject is a person of color. Just walking through a room where there is marijuana smoke could result in a positive hair test. Coarser hair absorbs and maintains the tell-tale signs much more than fine hair.

The accuracy of a given drug test is determined by:

  • The technology used in the test (accuracy varies considerably among types of tests)
  • The chemical nature of individual drugs (varies considerably from drug to drug)
  • The skills and abilities of the testing organization.
  • The procedures used to ensure proper handling and processing of samples.

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