Resources
What does an MRO do in DOT drug testing?
· All articles · Industries · FAQ
After a DOT urine or oral fluid specimen reaches the lab, a Medical Review Officer (MRO) reviews certain results before your third-party administrator or DER receives a verified report. That step protects donors with legitimate medical explanations and gives employers a consistent standard for what counts as a final result.
Collectors complete the collection and chain-of-custody paperwork; they are not the MRO and do not tell you whether to remove someone from a safety-sensitive role.
Supervisors should understand the MRO’s role so they do not react to early lab screens or rumors before the verified result arrives.
What the MRO actually does
The MRO is a licensed physician trained for federal drug testing review. For non-negative or invalid outcomes, the MRO may contact the donor in private about prescriptions and medical history, then apply DOT review standards.
When review finishes, the MRO reports a verified result to your TPA or DER path—negative, positive, refusal, or other categories your program recognizes.
That verified result is what should drive return-to-duty planning with a SAP, removal from safety-sensitive duty, or other steps your policy and counsel authorize—not a preliminary lab notification.
What employers should do—and avoid
Wait for your DER and TPA on what supervisors may hear and when. Premature discipline or hallway conversations about “a failed test” create risk even when the MRO later verifies negative.
Do not ask collectors or site leads to interpret prescriptions or argue with the MRO. Route medical questions through the process your TPA defines.
Keep the employee available for a confidential MRO call when requested; blocking contact can delay closure.
How collections fit the pipeline
We focus on qualified collections, identity checks, and specimen handling for DOT drug testing and blended sites. Lab routing and MRO assignment come from your TPA’s account setup.
If a result is non-negative, your next steps may involve SAP evaluation for return-to-duty—see our SAP guide for employers.
Official guidance
MRO qualifications and review duties for DOT programs are described in federal materials summarized by ODAPC at https://www.transportation.gov/odapc. Your TPA names the MRO on your account and can explain reporting timelines.
Put the logistics on our side
Share program type, locations, and timelines—we respond with coverage and scheduling options suited to employer operations.