How do drug tests work hair
How Do Drug Tests Work Hair for Reliable Long-Term Substance Detection
How do drug tests work hair? Hair follicle drug tests detect drug metabolites embedded in the hair shaft, providing a detection window of up to 90 days. Samples are collected at authorized sites and analyzed by national labs with results reviewed by certified Medical Review Officers. Call (877) 731-6362.
How do hair drug tests work in substance detection?
Hair drug tests work by analyzing a small sample of hair for drug metabolites that have entered the hair shaft from the bloodstream. When a person uses drugs, metabolites circulate in the blood and incorporate into the hair as it grows.
This method provides a longer detection window than urine or saliva testing, typically up to 90 days, depending on hair length. Hair follicle drug tests are used by employers, courts, and probation agencies to detect past drug use reliably.
How is hair collected for a drug test?
A trained collector cuts a small sample of hair, usually about 1.5 inches long and the diameter of a pencil, from the crown or another head area. If head hair is unavailable, body hair can be used but with a shorter detection window.
AMH Nationwide directs test requesters to a collection site affiliated with one of five national lab networks: Quest Diagnostics, LabCorp, Omega Labs, United States Drug Testing Labs, or ExperTox. There is no online ordering; all collections are in-person.
How do hair follicle drug tests work in the lab?
Once collected, the hair sample is sent to one of the national labs for analysis. The lab washes the hair to remove external contaminants, then uses specialized techniques like immunoassay screening followed by confirmatory testing via gas chromatography-mass spectrometry (GC-MS) or liquid chromatography-tandem mass spectrometry (LC-MS/MS).
Every non-negative screen undergoes review by a certified Medical Review Officer (MRO) to verify results and rule out legitimate medical explanations.
What is the detection window for hair follicle drug testing?
Hair follicle drug tests detect drug use from approximately 7 days after use up to 90 days prior. This is because hair grows about 0.5 inches per month, and the typical 1.5-inch sample reflects about three months of growth.
Short-term or very recent drug use may not be detected immediately, as the metabolites need time to reach the hair shaft. This makes hair testing useful for identifying longer-term patterns of drug use rather than recent consumption.
| Time Since Use | Detection Likelihood |
|---|---|
| Less than 7 days | Low to none |
| 7 to 90 days | High |
| More than 90 days | Unlikely |
Need a Hair Follicle Drug Test?
Contact AMH Nationwide to schedule your hair drug test collection at an authorized site. Call (877) 731-6362 for assistance and detailed information.
How do hair follicle drug tests differ from other drug tests?
Hair follicle drug tests differ from urine, saliva, or blood tests mainly in their longer detection window and collection process. They do not detect very recent drug use but are less invasive and harder to adulterate.
Unlike DOT-regulated urine tests, hair testing is generally used for non-DOT employment roles, legal cases, or individual testing. Urine tests are preferred for federally regulated safety-sensitive positions due to specific protocol requirements.
How reliable are hair follicle drug test results?
Hair follicle drug tests are highly reliable when conducted by accredited labs following strict protocols. AMH Nationwide works with SAMHSA-aligned, CAP, and CLIA-certified labs ensuring accuracy and chain-of-custody standards.
The involvement of certified Medical Review Officers reviewing all non-negative results adds an additional layer of oversight to prevent false positives or misinterpretation.
Common Questions
Hair follicle drug tests detect many common drugs including marijuana, cocaine, opiates, amphetamines, and PCP. The specific panel tested varies by request, so call (877) 731-6362 for details on available drug panels.
Hair follicle tests detect drug metabolites from about 7 days after use up to 90 days prior. Very recent drug use may not be detected because metabolites take time to incorporate into growing hair.
Passive exposure is unlikely to cause a positive hair drug test because the lab washes hair samples before analysis and tests for metabolites rather than just drug presence.
No. DOT-regulated safety-sensitive testing requires urine testing under federally certified protocols. Hair testing is for non-DOT roles and other testing purposes.
Collection is performed by trained professionals at authorized sites following strict chain-of-custody procedures to protect privacy and ensure sample integrity.
Pricing varies by test panel and detection window. Contact AMH Nationwide at (877) 731-6362 for a personalized quote.
Ready to get started?
AMH Nationwide provides the lab order and arranges collection nationwide. Every non-negative result reviewed by a certified Medical Review Officer. Call (877) 731-6362 or contact us.