Does thc show up in hair follicle drug test
Does THC Show Up in Hair Follicle Drug Test and What You Should Know
Does THC show up in hair follicle drug test? Yes, hair follicle drug tests detect THC metabolites, reflecting marijuana use over 90 days or more. They are used by employers, courts, and probation agencies for reliable long-term detection. Testing is conducted through national labs including Quest Diagnostics, LabCorp, Omega Labs, United States Drug Testing Labs, and ExperTox. Call (877) 731-6362.
Does THC show up in hair follicle drug test?
Yes, THC, the active compound in marijuana, shows up in hair follicle drug tests as a metabolite called THC-COOH incorporated into the hair shaft.
Hair follicle tests detect drug use over an extended period, typically up to 90 days, making them effective for identifying repeated or long-term marijuana use.
How long does marijuana stay detectable in a hair follicle drug test?
Marijuana use can be detected in hair follicles for up to 90 days or longer, depending on hair length and growth rate.
Hair grows approximately 0.5 inches per month, and most tests analyze 1.5 inches of hair closest to the scalp to assess drug use during the past three months.
How is the hair follicle drug test for THC conducted?
A small sample of hair, typically about 100 strands, is collected close to the scalp to maximize detection of recent drug use.
The sample is sent to one of five national lab networks: Quest Diagnostics, LabCorp, Omega Labs, United States Drug Testing Labs, or ExperTox for analysis.
All non-negative results are reviewed by a certified Medical Review Officer (MRO) to confirm accuracy and interpret findings.
Who typically orders hair follicle drug tests for THC?
Employers use hair follicle tests to screen safety-sensitive positions and pre-employment candidates for long-term drug use.
Courts and probation agencies may require hair testing to monitor compliance during supervision.
Individuals may also request testing for personal or legal reasons, although AMH Nationwide does not offer online ordering; scheduling requires calling (877) 731-6362.
Schedule a Hair Follicle Drug Test for THC
To arrange a hair follicle drug test for THC, call (877) 731-6362. AMH Nationwide directs you to one of 20,000+ collection sites and routes your sample to accredited national labs for processing.
Can hair follicle tests reliably detect weed or marijuana use?
Hair follicle tests are highly reliable for detecting marijuana use over months because THC metabolites bind to hair proteins and remain stable.
Passive exposure to marijuana smoke is unlikely to produce a positive hair test result, as detection thresholds require metabolite incorporation from actual use.
DOT-regulated safety-sensitive testing requires urine testing under 49 CFR Part 40; hair testing is used for non-DOT roles.
Are there limitations to hair follicle drug testing for THC?
Hair treatments like bleaching or dyeing can affect test results but do not guarantee evasion of detection.
One-time or very recent marijuana use may not be detected immediately as hair grows slowly and the drug metabolite needs time to incorporate.
Test panels and detection windows vary, so call (877) 731-6362 for specific information and pricing.
Common Questions
A single marijuana use may not be immediately detectable on a hair follicle test because the hair needs time to grow and incorporate THC metabolites. Typically, the detection window reflects use over the past 90 days.
Passive exposure to marijuana smoke is unlikely to cause a positive hair follicle test, as the test detects metabolites formed inside the body after actual use, not environmental contamination.
Approximately 100 strands of hair, about 1.5 inches in length from the scalp, are collected for analysis. This sample reflects drug use over roughly three months.
No. DOT-regulated safety-sensitive testing requires urine testing under federal guidelines (49 CFR Part 40). Hair follicle testing is used for non-DOT roles.
All non-negative hair follicle test results are reviewed by a certified Medical Review Officer (MRO) to verify accuracy and provide an official interpretation.
Chemical hair treatments such as bleaching or dyeing may reduce metabolite levels but do not guarantee a negative result. Labs account for such factors during testing.
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.