How a Hair Follicle Test Is Performed for Reliable Drug Detection

What is a hair follicle test and how is it performed?

A hair follicle test is a drug screening method that detects drug metabolites embedded in hair strands. It is performed by collecting approximately 1.5 inches of hair from close to the scalp, usually from the crown area. This length represents about 90 days of drug use history.

Once collected, the hair sample is sent to one of five national lab networks: Quest Diagnostics, LabCorp, Omega Labs, United States Drug Testing Labs, or ExperTox for laboratory analysis. The results are reviewed by a certified Medical Review Officer to ensure accuracy and compliance with testing standards.

How is a hair follicle drug test performed during collection?

The collection process for a hair follicle drug test is straightforward and non-invasive. A trained collector cuts a small sample of hair approximately the diameter of a pencil from the donor’s scalp, typically from the crown area. If scalp hair is unavailable, body hair may be collected, but this can affect the detection window.

The hair sample is placed in a secure container and labeled to maintain chain of custody. The collector ensures proper documentation and seals the sample before it is sent to the designated lab network for testing. This process follows strict protocols to prevent contamination or tampering.

How do labs analyze hair follicle samples for drugs?

Labs use advanced techniques such as immunoassay screening followed by gas chromatography-mass spectrometry (GC-MS) or liquid chromatography-tandem mass spectrometry (LC-MS/MS) to detect drug metabolites in hair samples.

The analysis can detect a wide range of substances including marijuana, cocaine, opiates, amphetamines, and phencyclidine (PCP). The testing window typically covers drug use within the previous 90 days based on hair growth rates.

Every non-negative result undergoes review by a certified Medical Review Officer who evaluates the findings and any relevant medical explanations before reporting final results.

What detection window does a hair follicle test cover?

A hair follicle test generally detects drug use within the past 90 days. Hair grows approximately 0.5 inches per month, so a 1.5-inch hair sample can reveal drug metabolites deposited during that timeframe.

This extended detection window makes hair follicle testing useful for employers, courts, and probation agencies seeking long-term drug use history. It does not detect very recent use within the last 5 to 7 days because it takes time for drugs to incorporate into hair strands.

Who typically requests hair follicle drug testing?

Hair follicle drug tests are commonly ordered by employers for pre-employment, random, or post-incident screening when long-term drug use history is relevant.

Courts and probation departments may also use hair testing for compliance monitoring. Individuals may request this test for personal reasons or legal cases. AMH Nationwide facilitates all requests by providing lab orders and directing clients to nearby collection sites within our national network.

Are there special protocols for hair follicle testing?

Hair follicle testing is not regulated under the Department of Transportation (DOT) urine testing rules, which require federally certified urine collection protocols under 49 CFR Part 40.

Because hair testing is for non-DOT safety-sensitive roles, collection protocols focus on proper sample size, chain of custody, and lab accreditation. AMH Nationwide works with SAMHSA-aligned, CAP, and CLIA accredited labs to ensure reliable testing and certified Medical Review Officer oversight.

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