Hair Drugs of Abuse Testing

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Hair Drugs of Abuse Testing

Drug detection times vary depending on the dose, sensitivity of the testing method used, preparation and route of administration, duration of use (acute or chronic), the matrix that is analyzed, the molecule or metabolite that is looked for, the pH and concentration of the matrix (urine, oral fluid), and variations in metabolic and renal clearance.2 In general, the detection time is longest in hair, followed by urine and oral fluid.2 Drugs in hair may be detectable for approximately 90 days, whereas drugs in urine are generally detectable for one to seven days or longer in chronic users and in oral fluid from five to 48 hours.2

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Hair growth rates vary; typically, head hair grows at an average of one-half inch per month. Therefore, a 1.5-inch hair sample detects drug use up to 90 days prior to testing.1

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A hair drug test with initial screen and confirmation requires 100 milligrams of hair (90 to 120 strands).

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Drug and drug metabolite(s) are incorporated into the hair matrix from the bloodstream following drug use. Hair drug testing detects drugs that are embedded in the hair.1

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2. Verstraete, AG. Detection times of drugs of abuse in blood, urine, and oral fluid. Ther Drug Monit. 2004;28(2):200-205.

Proposed revisions to Mandatory Guidelines for Federal Workplace Drug Testing Programs. Federal Register. April 11, 1988; 53:11970; amended June 9, 1994; 59:29908; September 30, 1997; 62:51118; April 13, 2004; 69:19675-19676,19679,19697- 19698.

1. Proposed revisions to Mandatory Guidelines for Federal Workplace Drug Testing Programs. Federal Register. April 11, 1988; 53:11970; amended June 9, 1994; 59:29908; September 30, 1997; 62:51118; April 13, 2004; 69:19675-19676,19679,19697- 19698.

Frequently Asked Questions