--- title: "Can a hair follicle test go back 6 months" description: "Can a hair follicle test go back 6 months? Hair testing can detect drug use up to 90 days. Learn more about detection windows. Call (877) 731-6362." author: "AMH Nationwide" date: "2026-08-28" tags: ["can a hair follicle test go back 6 months", "can a hair follicle test go back 6 months | can a hair follicle drug test go back 6 months"] canonical: "https://amhnationwide.com/can-a-hair-follicle-test-go-back-6-months/" last_updated: "2026-08-28" --- # Can a hair follicle test go back 6 months **By AMH Nationwide** | August 28, 2026 Can a hair follicle test go back 6 months? Hair testing can detect drug use up to 90 days. Learn more about detection windows. Call (877) 731-6362. --- Can a hair follicle test go back 6 months? Hair follicle drug tests typically detect drug use within a 90-day window, not 6 months. The test analyzes the segment of hair closest to the scalp, reflecting recent months only. For precise detection windows and testing options, call (877) 731-6362. [DETECTION WINDOW](https://amhnationwide.com/hair-follicle-drug-test-detection-window/) ## Can a hair follicle test go back 6 months? A hair follicle test cannot reliably detect drug use going back 6 months. Standard hair follicle drug testing examines approximately 1.5 inches of hair closest to the scalp, representing about 90 days of growth. Hair grows roughly half an inch per month, so the test window is limited to about three months. Longer hair can be segmented and tested to extend the detection window. However, testing beyond 90 days is uncommon and less reliable due to hair treatments, environmental factors, and sample integrity. Most labs, including the five national networks AMH uses, focus on the 90-day window for accuracy and consistency. Hair growth rate: ~0.5 inch per month Standard test length: 1.5 inches of hair Typical detection window: up to 90 days Longer hair can be tested but results beyond 90 days are less reliable For employer or court-ordered testing, the 90-day window is standard and accepted. Contact AMH at (877) 731-6362 to discuss your specific testing needs. TESTING BASICS ## How does a hair follicle drug test work? A hair follicle drug test detects drug metabolites deposited in hair shafts from the bloodstream after drug use. A small sample of hair, typically from the scalp, is collected and sent to a lab for analysis. Labs segment the hair to isolate the portion closest to the scalp, representing recent drug exposure. Testing is performed by certified laboratories including [Quest Diagnostics](https://www.questdiagnostics.com/), [LabCorp](https://www.labcorp.com/), Omega Labs, United States Drug Testing Labs, and ExperTox, ensuring standardized and reliable results. Every non-negative result is reviewed by a certified Medical Review Officer as part of quality control. DETECTION DETAILS ## What drugs can a hair follicle test detect within 6 months? While hair testing can theoretically analyze longer hair segments to detect drug use beyond 3 months, most standard panels do not routinely test for periods up to 6 months due to decreased accuracy. Common drugs detected include: Amphetamines Cocaine Opiates Phencyclidine (PCP) Marijuana (THC) Benzodiazepines Barbiturates AMH directs test requests to labs that follow strict protocols, but for detection windows longer than 90 days, the reliability and acceptance of results diminish. Call (877) 731-6362 for test options and guidance. LIMITATIONS ## Can a hair follicle drug test go back 6 months reliably? Testing hair beyond 90 days is technically possible by segmenting longer hair samples, but results become less reliable and are rarely used in standard employment or legal testing. Factors affecting reliability include hair damage, cosmetic treatments, environmental exposure, and variability in hair growth rates. Because of these factors, labs do not commonly offer 6-month detection tests as a standard service. For DOT-regulated safety-sensitive positions, hair testing is not approved; [urine](https://amhnationwide.com/urine-drug-testing/) testing under [49 CFR Part 40](https://www.transportation.gov/odapc/part40) is required. Hair testing is primarily for non-DOT roles. ## Need a Hair Follicle Test? Call (877) 731-6362 to arrange a hair follicle drug test or discuss detection windows with an AMH representative. [Call (877) 731-6362](tel:+18777316362)[Contact Us](https://amhnationwide.com/contact-us/) ORDERING ## How do I arrange a hair follicle test with AMH Nationwide? AMH Nationwide provides lab orders and directs individuals to one of 20,000+ nationwide collection sites affiliated with Quest Diagnostics, LabCorp, Omega Labs, United States Drug Testing Labs, and ExperTox. There is no online ordering. To arrange testing, call (877) 731-6362 to receive your lab order and collection site details. Pricing varies by test panel and detection window. Call for a quote and specific information. RESULTS ## What happens after a hair follicle test sample is collected? After collection, the hair sample is sent to the lab for analysis according to established protocols. All non-negative results undergo review by a certified Medical Review Officer (MRO) to confirm findings and assess any legitimate medical explanations. Test results are generally available within several days to a week depending on the lab and test panel. AMH Nationwide can assist with interpreting results or next steps. 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 Yes, chemical treatments like bleaching or dyeing can damage hair and potentially reduce detectable drug metabolites, but labs account for this during analysis. Yes, hair follicle testing is widely accepted for employment and legal purposes, especially when a longer detection window than urine testing is needed. Typically, about 1.5 inches of hair closest to the scalp is required, representing approximately 90 days of growth. Passive exposure is unlikely to produce a positive hair test because drug metabolites must be incorporated into the hair from the bloodstream. Hair testing for DOT safety-sensitive positions is not approved; urine testing under 49 CFR Part 40 is required for those roles. If scalp hair is too short, body hair may be collected, but detection windows and interpretation can vary. Contact AMH at (877) 731-6362 for guidance. 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/can-a-hair-follicle-test-go-back-6-months/