--- title: "Hair drug test" description: "Learn how far back a hair drug test can detect drug use. Accurate hair follicle drug screens with certified review. Call (877) 731-6362 to schedule." author: "AMH Nationwide" date: "2026-08-28" tags: ["hair drug test", "hair drug test | hair follicle drug test near me | how far back does a hair test go back | how far back will hair drug test go | how far can a drug test go back with hair | hair follicle test | hair follicle drug screen | how far back does a drug hair test go | how far back does a hair drug test go back | drugs detected in hair"] canonical: "https://amhnationwide.com/hair-drug-test/" last_updated: "2026-08-28" --- # Hair drug test **By AMH Nationwide** | August 28, 2026 Learn how far back a hair drug test can detect drug use. Accurate hair follicle drug screens with certified review. Call (877) 731-6362 to schedule. --- A hair drug test detects drug use by analyzing hair follicles for substance metabolites, typically covering up to 90 days prior. This test identifies multiple drugs with high accuracy and is reviewed by a certified Medical Review Officer. For scheduling or lab locations, call (877) 731-6362. OVERVIEW ## What is a hair drug test? A hair drug test is a laboratory analysis that detects drug metabolites deposited in hair strands. Unlike [urine](https://amhnationwide.com/urine-drug-testing/) or saliva tests, it identifies drug use over a longer period, usually up to 90 days. The test involves collecting a small sample of hair, usually from the scalp, which is then sent to one of five national lab networks for analysis: [Quest Diagnostics](https://www.questdiagnostics.com/), [LabCorp](https://www.labcorp.com/), Omega Labs, United States Drug Testing Labs, or ExperTox. Every non-negative result undergoes review by a certified Medical Review Officer to ensure accuracy and compliance with regulations. Collection sample: Hair strands from the scalp [Detection window](https://amhnationwide.com/hair-follicle-drug-test-detection-window/): Up to 90 days of drug history Lab networks: Quest Diagnostics, LabCorp, Omega Labs, United States Drug Testing Labs, ExperTox Result review: Certified Medical Review Officer AMH Nationwide directs the requester to a certified collection site; there is no online ordering. Call (877) 731-6362 to arrange testing. DETECTION WINDOW ## How far back does a hair drug test go back? A hair drug test typically detects drug use within the past 90 days. This is because hair grows approximately one half inch per month, and labs often analyze the most recent 1.5 inches of hair closest to the scalp. The test can reveal drug metabolites embedded in the hair shaft, reflecting cumulative use rather than recent or single use. This long detection window makes it suitable for employment screening, legal cases, and [probation](https://amhnationwide.com/hair-follicle-drug-test-probation/) monitoring. Standard detection window: 90 days Hair growth rate: ~0.5 inch per month Sample length analyzed: Usually 1.5 inches Detects chronic and past drug use For specific cases, detection windows might vary slightly based on hair length and testing panel. Contact AMH at (877) 731-6362 for detailed information. DRUGS TESTED ## What drugs can be detected in a hair drug test? Hair follicle drug tests detect a broad range of substances by identifying drug metabolites in hair strands. Commonly screened drugs include: Amphetamines Cocaine Marijuana (THC) Opiates (e.g., heroin, morphine) Phencyclidine (PCP) Methadone Benzodiazepines Barbiturates MDMA (Ecstasy) The exact drugs included depend on the testing panel selected. Call (877) 731-6362 to confirm available panels and pricing. TESTING PROCESS ## How is a hair follicle drug test performed? The test requires collecting about 100-120 strands of hair from the scalp or another body area if scalp hair is unavailable. The sample is sealed and sent to one of the accredited national labs. Testing involves washing the hair to remove external contaminants, then chemically analyzing it for drug metabolites. The entire process complies with strict chain-of-custody protocols to ensure result integrity. Sample collection: 100-120 hair strands Collection sites: Nationwide through AMH Laboratories: Quest Diagnostics, LabCorp, Omega Labs, United States Drug Testing Labs, ExperTox Result review: Certified Medical Review Officer AMH Nationwide does not offer online ordering. To schedule a hair follicle drug test near me or for other questions, call (877) 731-6362. ## Schedule Your Hair Follicle Drug Test Today To arrange a hair drug test with certified lab analysis and Medical Review Officer oversight, call (877) 731-6362. AMH Nationwide will direct you to a nearby collection site. [Call (877) 731-6362](tel:+18777316362)[Contact Us](https://amhnationwide.com/contact-us/) DOT & REGULATORY ## Is a hair drug test accepted for DOT-regulated testing? Hair drug testing is not accepted for Department of Transportation (DOT) safety-sensitive positions. DOT regulations require urine drug testing following the federally certified urine protocol under [49 CFR Part 40](https://www.transportation.gov/odapc/part40). Hair follicle tests are used for non-DOT roles where longer detection windows are desired. Employers must follow proper protocols and use authorized laboratories for compliance. DOT testing: Urine only, per 49 CFR Part 40 Hair tests: Non-DOT roles only Lab review: Certified Medical Review Officer standard AMH labs: Quest Diagnostics, LabCorp, Omega Labs, United States Drug Testing Labs, ExperTox For DOT-regulated testing, contact AMH at (877) 731-6362 to arrange urine drug testing services. COMMON QUESTIONS ## Can a hair drug test detect one-time or passive drug exposure? Hair drug tests are designed to detect drug metabolites that accumulate in hair after drug use. One-time or very infrequent use may be less likely to produce detectable levels, but it depends on the drug and amount used. Passive exposure, such as being in a smoky environment, generally does not result in a positive hair test because external contaminants are removed during lab washing procedures. The test focuses on internal metabolites incorporated into hair. One-time use: May be detected depending on dosage and drug Passive exposure: Usually not detected due to lab washing Test sensitivity: High, but varies by substance and panel For specific concerns about detection limits, call AMH at (877) 731-6362 to discuss testing options. AMH Reviewed & Maintained By AMH Nationwide Customer Service AMH Nationwide is BBB A+ accredited and routes every order through Quest Diagnostics, LabCorp, Omega Labs, United States Drug Testing Labs, or ExperTox, all of which use multiple lab certification agencies and standards such as [SAMHSA](https://www.samhsa.gov/workplace/drug-testing)-aligned laboratory protocols, the ANSI National Accreditation Board for forensic testing and calibration, the College of American Pathologists (CAP), and Clinical Laboratory Improvement Amendments (CLIA). Every non-negative screen is reviewed by a certified Medical Review Officer as part of standard processing before a result is released, and chain-of-custody documentation is maintained on every collection. This page does not constitute medical or legal advice. **Last updated:** July 2026 You May Also Need [Nail Drug TestingNo head or body hair available? A 5-panel fingernail test covers a similar look-back window.Learn more →](https://amhnationwide.com/5-panel-fingernail-drug-test/)[ChildGuard: Environmental ExposureConcerned about a child or loved one? ChildGuard screens for exposure to drugs in their environment.Learn more →](https://amhnationwide.com/5-panel-hair-drug-test-environmental-exposure-childguard/)[Shorten the Detection WindowShortened options like 30 and 60 day hair panels are also available, useful when a urine test’s 1-3 day window is too short.Learn more →](https://amhnationwide.com/30-day-hair-drug-test/)[Hair ETG Alcohol TestAlso need alcohol testing? The hair ETG test screens for alcohol use, and can be added to the same collection.Learn more →](https://amhnationwide.com/etg-and-peth/) Frequently Asked Questions ## Common Questions Results typically take 3 to 5 business days after the lab receives the hair sample. Timing can vary by lab and test panel. Hair tests detect many common drugs, but not all substances are included in every panel. Contact AMH to confirm which drugs are tested. Hair collection is painless and non-invasive, involving cutting a small sample close to the scalp. Hair treatments like dyeing or bleaching may reduce metabolite concentrations but do not guarantee a negative result. Body hair can be used as an alternative, but detection windows may differ due to slower growth rates. Hair tests offer a longer detection window and are less susceptible to short-term adulteration, but urine tests detect very recent use more effectively. Sources • [SAMHSA – Mandatory Guidelines for Federal Workplace Drug Testing Programs](https://www.samhsa.gov/workplace/drug-testing) • [U.S. DOT – 49 CFR Part 40 – Procedures for Transportation Workplace Drug and Alcohol Testing Programs](https://www.transportation.gov/odapc/part40) • [CDC – National Center for Health Statistics – Drug Use FastStats](https://www.cdc.gov/nchs/fastats/drug-use.htm) • [Quest Diagnostics – Employer Solutions, Hair Testing Methodology](https://www.questdiagnostics.com/) • [LabCorp – Occupational Testing Services](https://www.labcorp.com/) ## 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. [Call (877) 731-6362](tel:+18777316362)[Contact Us](https://amhnationwide.com/contact-us/) --- **Need a drug, alcohol, HIV or STD test?** AMH Nationwide is a national lab testing agency operating since 2004, with more than 20,000 collection sites across the United States. Hair, urine, fingernail and blood testing, panels from 5 through 19, for individuals and employers. - Call: (877) 731-6377 - Find a collection site: https://amhnationwide.com/locations/ - Full page: https://amhnationwide.com/hair-drug-test/