For a negative result: 1–3 business days after lab reporting, or 2–4 days total from collection. Positive results take longer — the MRO must contact you first. Here is the full timeline, step by step.
Order a DOT Drug Test →An MRO (Medical Review Officer) is a licensed physician trained and certified under 49 CFR Part 40 to review all DOT drug test laboratory results. The MRO is not part of the collection process — they receive results directly from the SAMHSA-certified lab and are the final decision-maker on every result.
The MRO exists to protect donors from false positives. If a test comes back positive from the lab, the MRO contacts you privately to determine whether a legitimate medical explanation exists — a valid prescription, for example — before reporting the result to the employer. The employer sees only the final MRO determination, not the raw lab result.
Federal regulations prohibit the lab from reporting directly to the employer. The MRO is the only authorized party to report a verified result — positive or negative — to the DER (Designated Employer Representative).
From collection to reported result — what happens at each stage and how long each takes.
Donor provides observed or unobserved urine specimen at a DOT-certified collection site. Collector completes the federal custody and control form (CCF). Specimen is sealed, labeled, and shipped to a SAMHSA-certified laboratory — usually same-day or overnight.
The lab runs an initial immunoassay screen on all 5 substances. Negative screens go directly to the MRO for review. Non-negative screens proceed to GC/MS confirmatory testing before going to the MRO — this adds 1 additional business day.
The MRO calls you directly — not your employer — to discuss the result privately. You may provide documentation of a valid prescription or medical condition. The MRO evaluates whether the explanation is legitimate under DOT rules.
The MRO issues the final determination — negative, positive, cancelled, or test not performed — to the employer's DER. If positive, the result is also reported to the FMCSA Clearinghouse. A positive triggers immediate removal from safety-sensitive duties and the start of the Return to Duty process.
Yes. You have the right to contact the MRO directly. Request their contact information from the collection site or your employer's DER. The MRO may not discuss a positive result before the donor interview is complete, but can confirm whether your result is still under review.
Call back as soon as you can. The MRO will note the time of each contact attempt. You do not need to answer immediately, but delaying the callback extends the review period and — if you remain unreachable — the MRO will eventually involve your employer's DER to locate you.
No. A non-negative initial screen goes to GC/MS confirmation. GC/MS is far more specific and can rule out cross-reactivity that caused the initial screen to flag. Some initial screens come back non-negative but confirm as negative after GC/MS — this is reported to the employer as a negative.
Every DOT specimen is split into two bottles (A and B) at collection. If the MRO reports a confirmed positive, adulterated, or substituted result, you have 72 hours to request that the B bottle be sent to a second SAMHSA-certified lab for re-testing. This is your right under federal regulations. Request it immediately through the MRO — the 72-hour clock starts when the MRO notifies you of the result.
For a negative result, the employer is typically notified at the same time or just after you. For a non-negative, the MRO must attempt to contact you privately first — the employer's DER is only contacted if the MRO cannot reach you after reasonable attempts. The MRO does not report a positive to the employer until the donor interview is resolved.
Pre-employment, random, return-to-duty, or follow-up. Results reported through a certified MRO. Nationwide collection sites.
5-panel urine · DOT chain of custody · SAMHSA-certified lab · MRO-reviewed