After a DOT drug test, the sample goes to a certified laboratory, but the lab does not report the result directly to you or your employer. There's a required review step in between — here's exactly how it works and how to check your status.
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Step 1 — The lab tests the sample
The certified laboratory screens the sample and, for any non-negative screen, runs a confirmation test. A negative screen is reported as negative without further review at the lab level.
Step 2 — The Medical Review Officer (MRO) reviews it
Every result — negative or not — is reviewed by a Medical Review Officer (MRO), a licensed physician trained in DOT drug testing rules. The MRO's job is to verify the result before it's reported to anyone else. This is a federal requirement, not an optional step.
Step 3 — Non-negative results trigger a direct call to you
If your initial screen comes back non-negative, the MRO will contact you directly — not your employer — to ask if there's a legitimate medical explanation (a valid prescription, for example) before verifying the result one way or the other. This conversation is confidential.
Step 4 — The verified result is reported
Once verified, the MRO reports the final result (negative, positive, refusal, etc.) to your employer or C/TPA — not the underlying lab data, just the verified determination.
How long does it take?
- Negative results: typically available within 24–48 hours of the collection.
- Non-negative screens requiring MRO review: often 48–72 hours, sometimes longer if the MRO needs to reach you or review documentation.
How to check your result
You have a few options:
- Call your C/TPA or testing coordinator — they can tell you whether your result has been verified, though they generally can't release lab-level detail themselves.
- Wait for the MRO to call you — if your result needs review, they will reach out directly; you don't need to chase this down.
- Ask your employer's DER (Designated Employer Representative) — once a verified result is reported, your employer's DER will have it and can confirm your status for safety-sensitive duty.
What happens after a negative result?
Nothing further is required — you're cleared to continue safety-sensitive functions. Negative results are reported to your employer and, for pre-employment and other qualifying test types, may also feed into the FMCSA Clearinghouse record.
What happens after a positive result?
You are immediately removed from safety-sensitive duties. To return to work, you must complete the full SAP return-to-duty process: evaluation by a Substance Abuse Professional, any prescribed education or treatment, a negative return-to-duty test, and a follow-up testing schedule.
Frequently Asked Questions
How long does it take to get DOT drug test results?
Negative results are typically available within 24-48 hours. Results that need further review by the Medical Review Officer (a non-negative initial screen) can take longer, often 48-72 hours or more.
Who sees my DOT drug test result first?
The lab sends results to the Medical Review Officer (MRO), not directly to you or your employer. The MRO reviews and verifies the result, then reports the verified result to the employer or C/TPA.
Can I check my DOT drug test results myself?
You can call your C/TPA or testing coordinator to ask whether your result has been verified. If your result is non-negative, the MRO will contact you directly to discuss it before it is reported to your employer.
What happens if my result is positive?
The MRO will contact you to discuss any legitimate medical explanation before verifying a result as positive. If verified positive, you are removed from safety-sensitive duties and must complete the SAP return-to-duty process before driving again.
Reviewed by Chantal Gabriel, MD
Medical Director, Doctors Place, PLLC · FMCSA-Certified Medical Examiner. This guide is reviewed by a certified medical examiner for accuracy.