--- title: "Hair Follicle Drug Test: How It Works | AMH Nationwide" description: "Hair follicle drug test how it works involves sample collection, lab screening, confirmation, and MRO review. Understand the process. Call (877) 731-6362." author: "AMH Nationwide" date: "2026-08-27" tags: ["hair follicle drug test how it works"] canonical: "https://amhnationwide.com/hair-follicle-drug-test-how-it-works/" last_updated: "2026-08-27" --- # Hair Follicle Drug Test: How It Works | AMH Nationwide **By AMH Nationwide** | August 27, 2026 Hair follicle drug test how it works involves sample collection, lab screening, confirmation, and MRO review. Understand the process. Call (877) 731-6362. --- Hair follicle drug test how it works starts with collecting a small hair sample, which is then analyzed by national labs using screening and confirmation tests. Every non-negative result undergoes review by a certified Medical Review Officer. Call (877) 731-6362 for more information. COLLECTION ## How is a hair follicle drug test sample collected? A hair follicle drug test sample is collected by cutting a small amount of hair close to the scalp, usually from the crown or back of the head. The sample typically measures about 1.5 inches in length and weighs approximately 100 milligrams. The collection is performed at a designated site directed by AMH Nationwide. The process is non-invasive and usually takes only a few minutes. If scalp hair is unavailable, body hair may be collected as an alternative. Sample size: about 100 mg of hair, 1.5 inches long Collection site: crown or back of the head Alternative: body hair if scalp hair is insufficient Collection supervised by trained personnel at a national lab network site LAB ANALYSIS ## What happens to the hair sample at the lab? Once collected, the hair sample is 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. These labs follow strict protocols to ensure accurate analysis. The lab first performs an initial immunoassay screening to detect the presence of drugs or their metabolites embedded in the hair shaft. This screening identifies potential positive samples that require further testing. Labs involved: Quest Diagnostics, LabCorp, Omega Labs, United States Drug Testing Labs, ExperTox First step: immunoassay screening for drug presence Screening detects drugs incorporated into hair from bloodstream exposure CONFIRMATION ## How are positive hair follicle drug test results confirmed? Samples that screen positive undergo confirmatory testing using gas chromatography-mass spectrometry (GC-MS) or liquid chromatography-tandem mass spectrometry (LC-MS/MS). These methods precisely identify and quantify specific drug compounds. Confirmation testing reduces the risk of false positives and verifies the initial screening results. Only confirmed positives are reported as positives. Methods: GC-MS or LC-MS/MS for confirmation Purpose: precise identification and quantification of drugs Ensures reliability by eliminating false positives MRO REVIEW ## What role does the Medical Review Officer play in the process? Every non-negative hair follicle drug test result is reviewed by a certified Medical Review Officer (MRO). The MRO evaluates the test findings in the context of medical history, prescription medications, and other relevant information. The MRO may contact the individual to verify legitimate medical explanations before finalizing the test result. This step ensures accuracy and fairness in reporting. MRO reviews all non-negative results MRO verifies medical explanations for positive findings Adds an expert clinical layer to the testing process ## Need a Hair Follicle Drug Test? Call (877) 731-6362 to schedule a collection appointment or get detailed information about the hair follicle drug test process. [Call (877) 731-6362](tel:+18777316362)[Contact Us](https://amhnationwide.com/contact-us/) PROCESS FLOW ## What is the complete step-by-step process for a hair follicle drug test? The hair follicle drug test process begins with AMH Nationwide directing the requester to a collection site within the five national lab networks. After sample collection, the hair is analyzed through screening and confirmation phases before MRO review. This systematic approach ensures comprehensive detection and reliable results. | Step | Description | | --- | --- | | 1. Collection | Hair sample cut close to scalp at authorized site | | 2. Screening | Initial immunoassay test for drug presence | | 3. Confirmation | Positive screens tested by GC-MS or LC-MS/MS | | 4. MRO Review | Certified Medical Review Officer evaluates non-negative results | | 5. Reporting | Final test results sent to the requester | TESTING LIMITATIONS ## What are the detection windows and limitations of hair follicle drug testing? Hair follicle drug tests typically detect drug use within the previous 90 days, as drugs incorporate into hair as it grows. This makes it effective for identifying longer-term usage rather than recent use. However, hair color, cosmetic treatments, and individual metabolism can affect detection sensitivity. Hair testing does not detect very recent drug intake within the past 5-7 days. [Detection window](https://amhnationwide.com/hair-follicle-drug-test-detection-window/): approximately 90 days Not suitable for detecting very recent use (within 5-7 days) Factors affecting results: hair color, chemical treatments, growth rate 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, body hair can be collected if scalp hair is insufficient. However, body hair may have a less precise detection window due to differing growth rates. Results typically take several days to a week, depending on lab workload and confirmation testing requirements. No, hair follicle tests are not subject to DOT urine testing regulations under [49 CFR Part 40](https://www.transportation.gov/odapc/part40) and are used mainly for non-DOT roles. Commonly detected substances include marijuana, cocaine, opiates, amphetamines, PCP, and others, depending on the test panel. No, it is a non-invasive procedure involving cutting a small hair sample close to the scalp without pain. A certified Medical Review Officer reviews all non-negative results to verify any legitimate medical explanations before final reporting. 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-follicle-drug-test-how-it-works/