Understanding What Is Tested for in a Hair Follicle Test and Its Benefits

What is tested for in a hair follicle test?

A hair follicle test screens for a variety of drugs by analyzing a small sample of hair. The primary substances tested include marijuana, cocaine, opiates, amphetamines, and phencyclidine (PCP). The test detects drug metabolites embedded in the hair shaft, reflecting use over approximately 90 days.

Hair follicle testing is often used by employers, courts, and probation officers due to its extended detection window compared to urine or saliva tests.

What drugs are tested for in a hair follicle test?

The standard hair follicle drug test panel includes multiple drug classes. Specifically, it tests for:

Additional substances may be included depending on the testing panel requested by the ordering party.

How does a hair follicle drug test work?

A technician collects a small sample of hair, usually from the crown of the head, about 1.5 inches long which reflects approximately 90 days of drug use. The sample is sent to one of five national labs: Quest Diagnostics, LabCorp, Omega Labs, United States Drug Testing Labs, or ExperTox.

The labs analyze the hair for drug metabolites using advanced methods. If the initial screen is non-negative, a certified Medical Review Officer reviews the results to verify accuracy and rule out legitimate medical explanations.

What is the detection window for drugs in a hair follicle test?

Hair follicle tests can detect drug use typically within the last 7 to 90 days. The detection window begins approximately one week after drug use since it takes time for metabolites to be deposited in hair follicles.

This extended window makes hair testing useful for identifying repeated or historical drug use rather than recent or one-time use.

Can hair follicle tests detect passive exposure or one-time use?

Hair follicle testing is designed to detect active drug use, not passive exposure. Passive exposure generally does not result in sufficient metabolite levels to trigger a positive test.

One-time or very infrequent drug use may be below detection thresholds, but repeated use will accumulate metabolites in the hair, increasing detection likelihood.

Who orders hair follicle tests and how is collection arranged?

Hair follicle tests are ordered by employers, courts, probation agencies, or individuals. AMH Nationwide provides the lab order and directs the requester to one of over 20,000 nationwide collection sites.

There is no online ordering. To arrange testing or get a quote, call (877) 731-6362. Pricing varies by panel and detection window.

Is hair follicle testing used for DOT-regulated drug screening?

Hair follicle testing is not approved for Department of Transportation (DOT) safety-sensitive roles. DOT requires urine testing under the federally certified protocol outlined in 49 CFR Part 40.

Hair testing is used primarily for non-DOT roles and situations requiring longer detection periods.

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