What do hair follicles test for
What Do Hair Follicles Test For? Reliable Drug Detection Over Months
What do hair follicles test for? Hair follicle tests detect drug metabolites deposited in hair strands, identifying drug use up to 90 days prior. They reveal substances such as cocaine, marijuana, opiates, amphetamines, and PCP. This method provides a longer detection window than urine tests and is used by employers and courts. Call (877) 731-6362 to arrange testing.
What do hair follicles test for?
Hair follicle tests detect drug metabolites embedded in the hair shaft, providing a historical record of drug use. The primary substances tested include cocaine, marijuana (THC), opiates (such as heroin and morphine), amphetamines, methamphetamines, and phencyclidine (PCP).
Hair follicle testing is valued for its longer detection window compared to urine or saliva tests, typically identifying drug use within the past 90 days. This makes it useful for employers, courts, and probation officers who require evidence of longer-term patterns of substance use.
How is a hair follicle test performed?
A small sample of hair, usually about 1.5 inches long and the width of a pencil, is collected close to the scalp. This sample represents roughly 90 days of hair growth and drug exposure.
The sample is sent to one of AMH Nationwide’s five national lab partners: Quest Diagnostics, LabCorp, Omega Labs, United States Drug Testing Labs, or ExperTox. Each lab analyzes the hair for drug metabolites using validated scientific methods.
Non-negative results undergo review by a certified Medical Review Officer (MRO) to confirm findings and rule out legitimate medical explanations.
What drugs do hair follicles test for?
Hair follicle testing detects a range of commonly abused substances. The standard testing panels typically include: cocaine, marijuana (THC), opiates (including heroin, codeine, morphine), amphetamines (including methamphetamine), and phencyclidine (PCP).
Some labs offer expanded panels that may include benzodiazepines, barbiturates, MDMA (ecstasy), or synthetic cannabinoids, but these are less common and require specific requests.
Hair follicle tests measure drug metabolites, which are chemical byproducts formed when the body processes drugs, making the test highly reliable for confirming actual drug use rather than external contamination.
Contact AMH Nationwide to discuss specific drug panel options. Call (877) 731-6362 for details.
How long do hair follicle tests detect drug use?
Hair follicle tests typically detect drug use for up to 90 days prior to sample collection, depending on hair length and growth rate. This is significantly longer than urine tests, which usually detect recent drug use within days to weeks.
The detection window begins roughly 7-10 days after drug ingestion, as it takes time for metabolites to be incorporated into new hair growth. Therefore, hair tests do not detect very recent drug use within the past week.
Because hair grows approximately 0.5 inches per month, a 1.5-inch hair sample can provide a 90-day history of drug exposure. Longer hair samples may extend detection further but are less commonly used for standard testing.
Schedule a Hair Follicle Drug Test Today
To arrange hair follicle testing through AMH Nationwide and one of our five national lab networks, call (877) 731-6362. Our staff will direct you to a nearby collection site and explain the next steps.
Can hair follicle tests be affected by passive exposure or external contamination?
Hair follicle tests measure drug metabolites inside the hair shaft, which requires ingestion and metabolism of the drug. This significantly reduces the chance of false positives from passive exposure to drug smoke or environmental contamination.
Labs use washing procedures to remove external contaminants before analysis. Additionally, the presence of metabolites rather than parent drugs indicates actual drug use.
Because of these scientific safeguards, hair follicle testing is considered highly reliable and resistant to attempts to cheat or evade detection through external means.
Who uses hair follicle drug testing and why?
Hair follicle drug testing is commonly used by employers for pre-employment screening and ongoing workforce testing, especially when a longer drug use history is needed.
Courts and probation departments use hair testing to monitor compliance with drug-free conditions over extended periods.
Individuals may also request hair follicle tests for personal reasons or legal matters.
DOT-regulated safety-sensitive positions require federally certified urine testing under 49 CFR Part 40; hair testing is used for non-DOT roles only.
Common Questions
Typically, about 1.5 inches of hair closest to the scalp is collected, roughly the width of a pencil. This length covers approximately 90 days of drug use history.
Standard hair follicle drug tests do not detect alcohol. Separate specialized tests are required to detect alcohol metabolites in hair.
Hair color and type can slightly influence drug incorporation, but labs use scientifically validated methods to ensure accurate and consistent results regardless of hair characteristics.
Results from hair follicle testing typically take 3 to 5 business days after the lab receives the sample. Non-negative results undergo additional review by a Medical Review Officer.
Yes, hair follicle tests can detect even single instances of drug use since metabolites are deposited during hair growth, but detection depends on timing and hair length.
No, DOT-regulated safety-sensitive testing requires federally certified urine testing under 49 CFR Part 40. Hair follicle testing is used for non-DOT roles only.
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.