Hair follicle testing shows up constantly in conversations about trucking safety. It has a longer detection window than urine testing, it's harder to defeat, and a number of large carriers have run their own hair testing programs for years. So it's a reasonable question: if hair testing is already common in the industry, why doesn't it count for DOT compliance?
The short answer is that hair follicle testing is still not an authorized specimen type under 49 CFR Part 40, the federal rule that governs all DOT drug and alcohol testing. As of 2026, DOT-regulated tests must use urine or oral fluid (saliva) – nothing else satisfies a federally mandated test, no matter how sophisticated the method.
Need a compliant collection? WorkOccMed runs DOT and non-DOT drug and alcohol testing at 15,000+ certified sites nationwide, using only federally authorized specimen types and Part 40 chain-of-custody procedures.
Why hair testing isn't DOT-authorized yet
This isn't an oversight, and it isn't FMCSA dragging its feet by choice. The path to authorizing a new DOT testing method runs through the Department of Health and Human Services (HHS), not FMCSA:
- 2015 – FAST Act. Congress passed the Fixing America's Surface Transportation (FAST) Act, which allows DOT to accept hair testing – but only once HHS publishes final Mandatory Guidelines establishing the scientific and technical standards for it (things like cutoff levels, lab certification, and specimen validity testing).
- 2020 – Proposed guidelines. HHS issued proposed hair testing guidelines for public comment, years behind the FAST Act's original one-year deadline.
- Still pending. As of 2026, HHS has not finalized those guidelines. Until it does, FMCSA has no legal authority to accept hair testing for DOT purposes – the agency has said publicly that it doesn't dispute the merits of hair testing, only that the statutory precondition hasn't been met.
Oral fluid testing followed a similar path and cleared it: HHS finalized oral fluid guidelines and, once enough labs were certified, FMCSA added it as an authorized DOT method. Hair testing is stuck earlier in that same process.
FMCSA has already said no to a workaround
In late 2022, a coalition of large truckload carriers petitioned FMCSA for an exemption that would let them report positive hair test results into the FMCSA Drug and Alcohol Clearinghouse, even without final HHS guidelines. FMCSA denied the request. The agency's reasoning was straightforward: it is bound by HHS's Mandatory Guidelines for technical and scientific testing standards, and it cannot create a Clearinghouse exception around a specimen type that hasn't cleared that process. That denial still stands.
A pending bill would change this – but hasn't moved
Legislation aimed at closing this gap has been introduced in Congress: the Drug and Alcohol Clearinghouse Public Safety Improvement Act, introduced in the House in mid-2025, would require carriers to report positive hair test results (from both pre-employment and random testing) into the Clearinghouse for vehicles over 10,000 pounds. As of 2026 the bill remains in committee with no floor action, and FMCSA has separately signaled it may pursue its own Clearinghouse data changes through rulemaking rather than waiting on Congress. Nothing has changed the underlying rule yet – employers should not build compliance programs around a bill that hasn't passed.
What this means for motor carriers today
- You can still run a hair testing program as a matter of company policy – many carriers do, especially for pre-employment and post-accident screening – but it operates entirely outside the DOT/FMCSA framework.
- It cannot replace the DOT-required test. A driver still needs a urine or oral fluid test collected under Part 40 procedures for pre-employment, random, reasonable-suspicion, post-accident, return-to-duty, and follow-up testing events. See our FMCSA drug testing rules guide for how those six DOT test types work.
- A hair test result cannot go into the Clearinghouse. Only violations tied to a DOT-authorized specimen type get reported. A driver who fails a carrier's private hair test but has no DOT-reportable violation will not show up as "prohibited" in the Clearinghouse for that result.
- Keep the records separate and the policy in writing. Because hair testing sits outside Part 40, it should be documented as a distinct, company-level program – not blended into your DOT testing records – and applied consistently to avoid discrimination exposure. Our non-DOT drug testing guide covers how to structure a defensible supplemental program.
- Don't use it to bypass a random pool obligation. Hair testing has no bearing on your random testing consortium enrollment or selection rate requirements under Part 382.
What this means for drivers
If a prospective employer runs its own hair testing program and you test positive, that result is a private employment decision by that company – it is not reported to FMCSA and does not affect your Clearinghouse status or your ability to be hired elsewhere as a matter of federal record. It can still cost you that specific job, and some carriers share hair testing data through private industry databases separate from the Clearinghouse, so the practical impact on your employability can still be real even without a federal report. If you're unsure whether a company's testing program is DOT or non-DOT, ask directly – the panel, the specimen type, and what happens to a positive result are all different depending on which one you're in.
The bottom line
Hair follicle testing is a real tool that plenty of carriers already use, but it is not – and as of 2026 still is not – a substitute for DOT-mandated urine or oral fluid testing, and it cannot legally be reported into the FMCSA Clearinghouse. That status depends entirely on HHS finalizing guidelines that have now been pending for over a decade, or on Congress passing legislation that hasn't yet made it out of committee. Build your compliance program around what's actually authorized today, and treat hair testing – if you use it at all – as a supplemental, company-level policy layered on top of, not instead of, your DOT program.
Frequently Asked Questions
Is hair follicle testing an authorized DOT drug testing method?
No. Under 49 CFR Part 40, DOT-regulated testing must use urine or oral fluid (saliva). Hair testing has never been authorized for federally mandated testing because HHS has not finalized the scientific and technical guidelines Congress required before DOT can accept it.
Can a positive hair test show up in the FMCSA Clearinghouse?
No. Only results from DOT-authorized tests (urine or oral fluid, collected under Part 40 procedures) can be reported to the Clearinghouse. FMCSA has repeatedly denied industry requests to allow hair test results into the Clearinghouse, most recently rejecting a 2022 exemption petition from a group of large carriers.
Why hasn't hair testing been approved for DOT use yet?
The 2015 FAST Act allows DOT to accept hair testing, but only once the Department of Health and Human Services publishes final Mandatory Guidelines for it. HHS issued proposed guidelines in 2020 but still has not finalized them, so FMCSA has no legal authority to approve hair testing for DOT purposes.
Can an employer require a hair test in addition to the DOT urine test?
Yes. A motor carrier can require hair testing as part of its own company policy, separate from the federally mandated DOT test. That result is a private employment record, though – it cannot replace the DOT-required urine or oral fluid test, and it cannot be reported to the Clearinghouse.
Reviewed by Chantal Gabriel, MD
Medical Director, WorkOccMed Medical Group, PLLC – FMCSA-Certified Medical Examiner. This guide is reviewed by a certified medical examiner for accuracy. It is for general educational purposes and is not legal advice.