How long can drugs be detected in hair
How Long Can Drugs Be Detected in Hair Follicle Tests for Accurate Results
How long can drugs be detected in hair? Hair follicle drug tests can detect drug use for up to 90 days after use. These tests analyze hair samples collected at a certified lab network and reviewed by a Medical Review Officer. For lab-directed hair follicle testing, call (877) 731-6362.
How long can drugs be detected in hair follicle tests?
Hair follicle drug tests can detect drug metabolites in the hair shaft for approximately 90 days after drug use. This detection window is longer than urine or saliva tests, which typically detect recent use within days.
Hair grows about half an inch per month, so a 1.5-inch hair sample represents roughly three months of drug exposure. Laboratories analyze this segment to determine drug use history.
What is involved in hair follicle drug testing?
Hair follicle testing requires collection of a small hair sample, usually from the scalp. AMH Nationwide directs the requester to one of five national lab networks for collection: Quest Diagnostics, LabCorp, Omega Labs, United States Drug Testing Labs, or ExperTox.
The collected hair sample is sent to a certified laboratory where it is analyzed for drug metabolites. Every non-negative result is reviewed by a certified Medical Review Officer to ensure accuracy and proper interpretation.
Who typically orders hair follicle drug tests?
Hair follicle tests are commonly ordered by employers for pre-employment or ongoing employee drug screening, especially for positions requiring safety-sensitive roles outside of Department of Transportation (DOT) regulations.
Courts, probation officers, and individual clients may also request hair testing to verify long-term drug use. DOT-regulated testing requires federally certified urine testing under 49 CFR Part 40; hair testing is not accepted for DOT safety-sensitive roles.
How reliable are hair follicle drug tests?
Hair follicle drug tests provide a reliable detection method with a long detection window. Drug metabolites are incorporated into hair as it grows, making results less susceptible to short-term abstinence or passive exposure.
The use of five national lab networks and review by certified Medical Review Officers enhances result accuracy and reduces false positives or negatives.
Ready to Schedule Hair Follicle Drug Testing?
Contact AMH Nationwide to arrange lab-directed hair follicle drug testing through our national lab network. Call (877) 731-6362 for assistance.
What are the limitations of hair follicle drug testing?
Hair testing does not detect very recent drug use within the past 7 days because drugs take time to incorporate into hair.
Environmental contamination or cosmetic hair treatments may affect results but are considered during laboratory analysis and Medical Review Officer review.
Detection windows vary by drug type, hair growth rate, and individual metabolism.
How do I arrange hair follicle drug testing with AMH Nationwide?
AMH Nationwide provides the lab order and directs you to a collection site within its five national lab networks. There is no online ordering available.
Pricing varies depending on the drug panel selected and detection window required. Call (877) 731-6362 for a quote and to schedule testing.
Common Questions
Hair follicle tests can detect a single drug use event but only after about 7 days have passed for the drug to incorporate into the hair. The test reflects drug use over the prior 90 days.
Passive exposure is unlikely to cause a positive hair follicle test because the test detects drug metabolites inside the hair shaft, not external contamination. The Medical Review Officer reviews all non-negative results.
Since drugs take about 7 days to appear in hair, testing immediately after use may not detect the drug. Waiting at least 7 days ensures accurate detection.
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.
Hair follicle tests can detect a variety of drugs including marijuana, cocaine, opiates, amphetamines, PCP, and synthetic opioids. Panels vary by request.
Hair follicle drug tests are highly accurate when conducted through certified labs and reviewed by Medical Review Officers. They provide a reliable indication of drug use over the past 90 days.
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.