Understanding If a Hair Follicle Test Can Go Back 6 Months for Drug Detection

Can a hair follicle test go back 6 months?

A hair follicle test cannot reliably detect drug use going back 6 months. Standard hair follicle drug testing examines approximately 1.5 inches of hair closest to the scalp, representing about 90 days of growth. Hair grows roughly half an inch per month, so the test window is limited to about three months.

Longer hair can be segmented and tested to extend the detection window. However, testing beyond 90 days is uncommon and less reliable due to hair treatments, environmental factors, and sample integrity. Most labs, including the five national networks AMH uses, focus on the 90-day window for accuracy and consistency.

For employer or court-ordered testing, the 90-day window is standard and accepted. Contact AMH at (877) 731-6362 to discuss your specific testing needs.

How does a hair follicle drug test work?

A hair follicle drug test detects drug metabolites deposited in hair shafts from the bloodstream after drug use. A small sample of hair, typically from the scalp, is collected and sent to a lab for analysis.

Labs segment the hair to isolate the portion closest to the scalp, representing recent drug exposure. Testing is performed by certified laboratories including Quest Diagnostics, LabCorp, Omega Labs, United States Drug Testing Labs, and ExperTox, ensuring standardized and reliable results. Every non-negative result is reviewed by a certified Medical Review Officer as part of quality control.

What drugs can a hair follicle test detect within 6 months?

While hair testing can theoretically analyze longer hair segments to detect drug use beyond 3 months, most standard panels do not routinely test for periods up to 6 months due to decreased accuracy.

Common drugs detected include:

AMH directs test requests to labs that follow strict protocols, but for detection windows longer than 90 days, the reliability and acceptance of results diminish. Call (877) 731-6362 for test options and guidance.

Can a hair follicle drug test go back 6 months reliably?

Testing hair beyond 90 days is technically possible by segmenting longer hair samples, but results become less reliable and are rarely used in standard employment or legal testing.

Factors affecting reliability include hair damage, cosmetic treatments, environmental exposure, and variability in hair growth rates. Because of these factors, labs do not commonly offer 6-month detection tests as a standard service.

For DOT-regulated safety-sensitive positions, hair testing is not approved; urine testing under 49 CFR Part 40 is required. Hair testing is primarily for non-DOT roles.

How do I arrange a hair follicle test with AMH Nationwide?

AMH Nationwide provides lab orders and directs individuals to one of 20,000+ nationwide collection sites affiliated with Quest Diagnostics, LabCorp, Omega Labs, United States Drug Testing Labs, and ExperTox.

There is no online ordering. To arrange testing, call (877) 731-6362 to receive your lab order and collection site details.

Pricing varies by test panel and detection window. Call for a quote and specific information.

What happens after a hair follicle test sample is collected?

After collection, the hair sample is sent to the lab for analysis according to established protocols. All non-negative results undergo review by a certified Medical Review Officer (MRO) to confirm findings and assess any legitimate medical explanations.

Test results are generally available within several days to a week depending on the lab and test panel. AMH Nationwide can assist with interpreting results or next steps.

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