--- title: "How much hair do they take for a drug test" description: "Learn how much hair they take for a drug test and what influences the sample size. Get accurate details and lab process info. Call (877) 731-6362 today." author: "AMH Nationwide" date: "2026-08-28" tags: ["how much hair do they take for a drug test"] canonical: "https://amhnationwide.com/how-much-hair-do-they-take-for-a-drug-test/" last_updated: "2026-08-28" --- # How much hair do they take for a drug test **By AMH Nationwide** | August 28, 2026 Learn how much hair they take for a drug test and what influences the sample size. Get accurate details and lab process info. Call (877) 731-6362 today. --- How much hair do they take for a drug test depends on the testing requirements, but typically about 1.5 inches of hair length and a small bundle roughly the size of a pencil eraser is collected. This sample size allows labs to detect drug use over a 90-day period reliably. Call (877) 731-6362 for more details or to schedule a collection. SAMPLE SIZE ## How much hair do they take for a drug test? The typical amount of hair taken for a drug test is approximately 1.5 inches in length and about 100-120 strands, which is roughly the size of a pencil eraser or a small coin. This amount provides enough material for laboratories to conduct a thorough analysis of drug metabolites over an extended [detection window](https://amhnationwide.com/hair-follicle-drug-test-detection-window/). DETECTION WINDOW ## Why is the length of hair important in drug testing? The length of hair collected, usually 1.5 inches, corresponds to about a 90-day detection window. Hair grows approximately half an inch per month, so this length captures drug use over the past three months. Shorter samples provide less historical data, while longer samples may be more difficult to collect and process. COLLECTION PROCESS ## How is the hair sample collected for drug testing? A trained collector cuts hair close to the scalp, usually from the crown or back of the head, to ensure the sample reflects recent growth. The hair is placed in a tamper-evident envelope and sent to one of five national lab networks: [Quest Diagnostics](https://www.questdiagnostics.com/), [LabCorp](https://www.labcorp.com/), Omega Labs, United States Drug Testing Labs, or ExperTox. LAB ANALYSIS ## What happens to the hair sample after collection? Once collected, the hair sample undergoes initial screening for drug metabolites. Any non-negative results are reviewed by a certified Medical Review Officer (MRO) to confirm findings and rule out potential false positives. This review is standard for all AMH Nationwide drug test processing. ## Need to Know How Much Hair Is Taken for Your Drug Test? Call (877) 731-6362 to speak with a representative who can guide you through the hair drug testing process and help you find a nearby collection site. [Call (877) 731-6362](tel:+18777316362)[Contact Us](https://amhnationwide.com/contact-us/) TESTING REGULATIONS ## Are hair drug tests regulated differently for DOT and non-DOT testing? DOT-regulated safety-sensitive testing requires [urine](https://amhnationwide.com/urine-drug-testing/) testing under federally certified protocols ([49 CFR Part 40](https://www.transportation.gov/odapc/part40)). Hair testing is used primarily for non-DOT roles because it provides a longer detection window. AMH Nationwide follows all regulatory guidelines and directs collection accordingly. PRICING FACTORS ## Does the amount of hair taken affect the cost of the drug test? The amount of hair taken generally does not affect the cost directly. Pricing varies based on the drug panel selected and the detection window required. For a precise quote, contact AMH Nationwide directly. Collection is arranged through a local site with no online ordering. 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. Hair drug tests typically analyze 1.5 inches of hair, representing about 90 days of drug use history. Generally, yes. About 100-120 strands or a pencil eraser-sized sample is standard, but it may vary slightly depending on hair thickness. Body hair can be used if scalp hair is unavailable, but detection windows and test results may vary due to different growth rates. If hair is too short, a shorter detection window is tested, or alternative tests like urine may be recommended. Hair tests detect metabolites incorporated into hair shafts; passive exposure generally does not produce positive results confirmed by an MRO. All non-negative hair drug test results are reviewed by a certified Medical Review Officer to ensure accuracy and reliability. 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-much-hair-do-they-take-for-a-drug-test/