How much hair is required for a drug test
How Much Hair Is Required for a Drug Test to Ensure Accurate Results
How much hair is required for a drug test depends on the test type, but typically hair follicle testing requires about 1.5 inches of hair, roughly the length of a standard pencil. This length covers approximately 90 days of drug use history. AMH Nationwide routes collections through five national labs and reviews all non-negative results with a Medical Review Officer. Call (877) 731-6362.
How much hair is required for a hair follicle test?
For a hair follicle drug test, approximately 1.5 inches of head hair is required. This length corresponds to the typical detection window of about 90 days, as hair grows roughly half an inch per month. The sample is usually taken from the crown of the head to ensure consistency.
If head hair is not available, body hair may be used, but the detection window and results can vary due to different growth rates.
How much hair is needed in terms of quantity for testing?
The amount of hair needed for a follicle drug test is typically about 100 strands or roughly the diameter of a pencil eraser. This quantity allows the lab to conduct multiple tests if necessary and confirm results reliably.
AMH Nationwide directs collection at one of five national lab networks, ensuring proper sample size and handling for accurate testing.
What happens to the hair sample after collection?
Once collected, the hair 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. These labs analyze the hair for drug metabolites embedded in the hair shaft.
All non-negative results undergo review by a certified Medical Review Officer (MRO) to verify findings and rule out legitimate explanations.
How does the length of hair relate to the detection window?
The 1.5-inch hair length corresponds to about 90 days of drug use history because hair grows approximately 0.5 inches per month. Longer hair can provide a longer detection window, but most tests standardize on 1.5 inches for consistency.
Shorter hair samples may only show recent use, and if hair is too short or absent, alternative specimen types like urine or oral fluid may be used.
Need to Know How Much Hair Is Required for a Drug Test?
Contact AMH Nationwide to schedule your hair follicle drug test or get answers about sample requirements. Call (877) 731-6362 today.
Can insufficient hair length affect test results?
Yes, if the hair sample is shorter than the required 1.5 inches, the detection window shortens and some drug use history may not be detected. In cases where hair length is insufficient, the collector may request a different specimen type.
Collection sites directed by AMH Nationwide follow strict protocols to ensure enough hair is collected to meet testing standards.
How do I arrange a hair follicle drug test and hair collection?
AMH Nationwide provides the lab order and directs the requester to a nearby collection site from its network of over 20,000 nationwide locations. There is no online ordering; to arrange testing and collection, call (877) 731-6362.
Collection sites are trained to gather the proper hair length and quantity, following regulatory and lab requirements.
Common Questions
Yes, body hair can be used if head hair is unavailable or too short. However, body hair grows at different rates and may provide a less precise detection window. Labs assess suitability on a case-by-case basis.
If hair is too short or absent, a hair follicle test may not be possible. Alternative specimen types like urine or oral fluid tests may be recommended for drug screening.
Hair follicle testing detects drug metabolites incorporated into the hair shaft from the bloodstream, not from external contamination. Passive exposure typically does not produce a positive result under standard testing protocols.
Once the hair sample reaches the lab, results typically take 3 to 5 business days. All non-negative results are reviewed by a Medical Review Officer before reporting.
Pricing varies based on the testing panel and detection window. Contact AMH Nationwide at (877) 731-6362 for a custom quote and details.
No, DOT-regulated testing requires the federally certified urine protocol under 49 CFR Part 40. Hair follicle tests are 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.