How far back will hair drug test go
How Far Back Will Hair Drug Test Go for Reliable Drug Detection
How far back will hair drug test go depends on the length of the hair sample, typically up to 90 days. Hair follicle drug tests analyze drug metabolites embedded in hair shafts, providing a longer detection window than urine tests. Call (877) 731-6362 to arrange testing through AMH Nationwide.
How far back can a hair strand drug test go?
A hair strand drug test can detect drug use for approximately 90 days prior to collection. This is because hair grows about half an inch per month, and a standard test analyzes 1.5 inches of hair closest to the scalp. Longer hair samples can extend the detection window proportionally.
Hair follicle tests detect drug metabolites deposited in the hair shaft from the bloodstream, making it possible to review drug history over months rather than days.
How far back can a hair follicle test go compared to other tests?
Hair follicle tests provide a longer detection window than urine or saliva tests. While urine tests typically detect recent drug use within 1 to 4 days, hair follicle tests can detect drug metabolites for up to 90 days or more.
This extended detection window makes hair follicle testing suitable for employers, courts, and probation agencies requiring a comprehensive drug use history.
| Test Type | Typical Detection Window |
|---|---|
| Urine Test | 1 to 4 days |
| Saliva Test | 1 to 3 days |
| Hair Follicle Test | Up to 90 days |
What happens during hair drug testing at AMH Nationwide?
AMH Nationwide routes hair drug test specimens through five national lab networks: Quest Diagnostics, LabCorp, Omega Labs, United States Drug Testing Labs, and ExperTox. Each lab analyzes the hair sample for drug metabolites using scientifically validated methods.
All non-negative results are reviewed by a certified Medical Review Officer (MRO) to ensure accuracy and proper interpretation. This standard process supports reliable reporting.
Are hair drug tests regulated differently for DOT and non-DOT roles?
DOT-regulated safety-sensitive positions require urine drug testing under the federally certified protocol defined in 49 CFR Part 40. Hair testing is not authorized for DOT drug screening.
Hair drug tests are typically used for non-DOT workplace testing, legal cases, or individual requests where a longer detection window is needed.
Schedule Your Hair Drug Test Today
To learn how far back a hair drug test can go for your specific needs, call (877) 731-6362. AMH Nationwide will guide you to a convenient collection site and ensure accurate testing with certified lab networks.
Can hair drug tests detect one-time or passive drug exposure?
Hair drug tests detect drug metabolites incorporated into the hair during active drug use. One-time use can be detected if sufficient drug metabolites are present in the hair sample.
Passive exposure is unlikely to produce a positive hair test result because the testing methods differentiate between environmental contamination and actual drug ingestion.
How do I get a hair drug test through AMH Nationwide?
AMH Nationwide provides the lab order and directs you to the nearest collection site nationwide. There is no online ordering available. To schedule or inquire about hair drug testing, call (877) 731-6362.
Pricing varies by test panel and detection window. Contact AMH Nationwide for a personalized quote and assistance.
Common Questions
A hair follicle test typically detects drug use up to 90 days prior to the test date by analyzing 1.5 inches of hair closest to the scalp.
Yes, hair drug tests can detect one-time drug use if the drug metabolites are present in the hair sample at detectable levels.
No, DOT-regulated testing requires urine drug tests under the federally certified protocol. Hair drug testing is used for non-DOT testing purposes.
Passive exposure is unlikely to cause a positive hair drug test because labs differentiate between environmental contamination and drug ingestion.
A small sample of hair, typically 1.5 inches from the scalp, is cut from the head. If head hair is unavailable, body hair may be used with some limitations.
All non-negative hair drug test results are reviewed by a certified Medical Review Officer to confirm accuracy and interpret findings.
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.