My Driver Says He Took a Prescription. What Do I Do?

This article is for the owner or designated employer representative (DER) of a small fleet. Drivers often bring up a prescription at the collection site or call the boss when they're worried. Your job is smaller than you think.

What you do

Tell him to save it for the MRO. He doesn't need to tell the collector, and the collector doesn't write it on the custody form.
Make sure the MRO can reach him. If the lab result is positive, the MRO calls the driver for a private verification interview (40.131, 40.137). Confirm we have a working phone number for him.
If the MRO can't reach him, you'll be asked to help. You tell the driver to call the MRO, and nothing else. He has 72 hours. After that, the MRO can verify the result without hearing from him (40.133).
Wait for the MRO's result. Don't act on the lab's result, on the driver's story, or on a pill bottle he shows you.

What happens with a valid prescription

The MRO asks for the prescription and the prescribing doctor. If the medication explains the result, the MRO reports it to you as negative. You aren't told the drug, the doctor, or the condition. There is no violation and no Clearinghouse report.

When you'll hear more: the safety concern

Sometimes a medication is legal but could make the driver unsafe, like a strong opioid or a sedative. The MRO can give the driver five days to have his doctor call. If the concern remains, the MRO reports it to you along with the negative result (40.135(e), 40.327).

That's not a drug violation. It's a medical question. Keep the driver off the road and send him back to his DOT medical examiner, who decides whether he's qualified to drive under 49 CFR 391.41.

What doesn't count as a prescription

Someone else's pills. A spouse's or a friend's prescription is not a legitimate explanation. The result is verified positive.
An old or expired prescription. Only the MRO decides, and an expired prescription is one common reason the MRO does not change the result to negative.
A medical marijuana card. Whether the drug is legal isn't the issue. Safety is. In April 2026 the Justice Department moved state-licensed medical marijuana to Schedule III. DOT said in May 2026 that this changes nothing: DOT still tests for marijuana, and a state card does not excuse a positive.
CBD products. DOT does not accept CBD use as an explanation for a marijuana positive.
Cough syrup or mouthwash on an alcohol test. A prescription doesn't excuse a breath alcohol result. At 0.02 to 0.039 the driver is off duty for 24 hours. At 0.04 or higher, it's a violation.

The rule behind it

Under 49 CFR 382.213, a driver may use a controlled substance only if a licensed doctor prescribed it, knows his medical history and duties, and told him it won't affect his driving.

What TrueTest does

Gets the driver's contact information to the MRO so the interview happens fast.
Passes along the MRO's request if the driver can't be reached, so you know exactly what to tell him.
Sends you the final result once the MRO is done, not the raw lab result.

Questions DERs ask

Should I ask my driver what medication he's taking?

Not for the test. The MRO handles it confidentially, and you get a negative if it's legitimate.

Will a prescription show up as a positive?

It can show positive at the lab. The MRO reviews it, and a legitimate prescription is reported to you as negative.

Does a medical marijuana card excuse a positive DOT test?

No. DOT confirmed in May 2026 that marijuana's partial move to Schedule III doesn't change DOT testing.

What is an MRO safety concern?

A report that a legally prescribed medication may make the driver unsafe. It's not a violation. The driver sees his DOT medical examiner before driving again.