--- title: "How reliable are hair follicle drug tests" description: "How reliable are hair follicle drug tests? Hair follicle drug testing offers a detection window of up to 90 days and high accuracy. Call (877) 731-6362 to schedule." author: "AMH Nationwide" date: "2026-08-28" tags: ["how reliable are hair follicle drug tests", "how reliable are hair follicle drug tests | how reliable is hair drug testing | are hair follicle drug tests reliable | how reliable is hair follicle drug test | how reliable is hair follicle drug testing | is a hair follicle drug test reliable"] canonical: "https://amhnationwide.com/how-reliable-are-hair-follicle-drug-tests/" last_updated: "2026-08-28" --- # How reliable are hair follicle drug tests **By AMH Nationwide** | August 28, 2026 How reliable are hair follicle drug tests? Hair follicle drug testing offers a detection window of up to 90 days and high accuracy. Call (877) 731-6362 to schedule. --- How reliable are hair follicle drug tests? Hair follicle drug tests are highly reliable for detecting drug use within approximately 90 days prior to collection, with results reviewed by certified Medical Review Officers. These tests are less susceptible to short-term fluctuations than urine tests. For accurate testing through national labs, call (877) 731-6362. OVERVIEW ## How reliable is hair follicle drug testing for detecting drug use? Hair follicle drug testing is considered reliable for detecting drug metabolites deposited in hair shafts over a period of up to 90 days. The test analyzes a small hair sample, typically about 1.5 inches in length, which reflects drug intake during that time frame. This method is less vulnerable to short-term drug use fluctuations compared to [urine](https://amhnationwide.com/urine-drug-testing/) or saliva tests. At AMH Nationwide, all hair follicle drug tests are processed through one of five national lab networks: [Quest Diagnostics](https://www.questdiagnostics.com/), [LabCorp](https://www.labcorp.com/), Omega Labs, United States Drug Testing Labs, and ExperTox. Each non-negative result undergoes review by a certified Medical Review Officer (MRO), ensuring accuracy and proper interpretation. [DETECTION WINDOW](https://amhnationwide.com/hair-follicle-drug-test-detection-window/) ## What is the detection window for hair follicle drug tests? Hair follicle drug tests detect drug use within an approximate 90-day window. This is because hair grows roughly 0.5 inches per month, and a standard 1.5-inch hair sample represents about three months of growth. Drugs and their metabolites are incorporated into the hair shaft from the bloodstream during this time. Detection window: up to 90 days Sample length: standard 1.5 inches of hair Effective for detecting long-term or repeated drug use Not suitable for detecting very recent drug use (within 7 days) ACCURACY ## Are hair follicle drug tests reliable in terms of accuracy? Hair follicle drug tests are highly accurate when performed by certified labs following standardized protocols. The use of advanced analytical methods such as immunoassay screening followed by confirmatory testing with gas chromatography-mass spectrometry (GC-MS) or liquid chromatography-tandem mass spectrometry (LC-MS/MS) minimizes false positives. AMH Nationwide ensures that all testing is conducted through [SAMHSA](https://www.samhsa.gov/workplace/drug-testing)-certified labs with CAP and CLIA accreditation, further supporting test reliability. FALSE POSITIVES AND LIMITATIONS ## Can hair follicle drug tests produce false positives or false negatives? While hair follicle drug tests are generally reliable, false positives can occasionally occur due to environmental contamination or certain cosmetic hair treatments. However, confirmatory testing and review by a Medical Review Officer help reduce these occurrences. False negatives may happen if the hair sample is too short, chemically treated, or if the individual has very light or no hair in the tested area. Additionally, hair tests do not detect very recent drug use within about 7 days since drugs take time to incorporate into hair. ## Schedule Reliable Hair Follicle Drug Testing Today To arrange accurate hair follicle drug testing through certified national labs, call AMH Nationwide at (877) 731-6362. Our staff will assist with lab orders and collection site referrals. [Call (877) 731-6362](tel:+18777316362)[Contact Us](https://amhnationwide.com/contact-us/) WHO ORDERS ## Who typically orders hair follicle drug testing and why? Employers, legal entities, [probation](https://amhnationwide.com/hair-follicle-drug-test-probation/) officers, and individuals seeking long-term drug use history often choose hair follicle drug testing. It is particularly useful for safety-sensitive roles where knowledge of drug use over several months is required. Because hair testing is not accepted for Department of Transportation (DOT) safety-sensitive positions, urine testing under [49 CFR Part 40](https://www.transportation.gov/odapc/part40) is mandated for those roles. TESTING PROCESS ## How does AMH Nationwide handle hair follicle drug testing? AMH Nationwide provides the lab order and directs the requester to one of over 20,000 nationwide collection sites. We do not offer online ordering. Collected samples are sent to one of the five national lab networks for analysis. Every non-negative hair follicle drug test result is reviewed by a certified Medical Review Officer as part of standard processing to ensure accurate interpretation and reporting. 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-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 Hair follicle drug tests are not reliable for detecting drug use within the past 7 days because it takes time for drugs to incorporate into hair strands. For recent use, urine or saliva testing is more appropriate. Certain hair treatments like bleaching, dyeing, or perming can reduce drug metabolite concentrations in hair, potentially affecting test results. However, certified labs account for this during analysis. Labs use a two-step process: initial immunoassay screening followed by confirmatory testing using GC-MS or LC-MS/MS. Additionally, Medical Review Officers evaluate all positive results to rule out false positives. Hair follicle drug tests commonly detect substances including amphetamines, cocaine, marijuana (THC), opioids, phencyclidine (PCP), and benzodiazepines, among others. AMH Nationwide provides lab orders and directs clients to authorized collection sites nationwide. We do not perform collections ourselves. Pricing varies based on the test panel and detection window. For a quote and detailed information, call (877) 731-6362. 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/how-reliable-are-hair-follicle-drug-tests/