Can an MRO Report Marijuana Positive as Negative for State-Legal Use?

No. Currently, there is no situation in which a What is a Medical Review Officer? (MRO) can verify a laboratory confirmed marijuana positive drug test result as negative when an employee claims the positive came from using a state-licensed marijuana product.

Even after rescheduling, state-dispensed marijuana does not constitute an FDA-approved drug. Without FDA approval for a controlled substance, it cannot be prescribed. A legitimate medical explanation requires the use of a legally prescribed controlled substance in compliance with Federal laws governing such a prescription (49 CFR sections 40.137(a) and 40.141(b)).

Although the MRO may be presented with documentation such as state-issued medical marijuana cards, physician recommendations, certifications, or dispensary records or receipts, these documents do not satisfy Part 40 requirements for a legitimate medical explanation. Marijuana use under state marijuana programs or other non-prescription sources does not qualify as a legitimate medical explanation under 49 CFR section 40.137(a). In addition, marijuana use is not compatible with safety-sensitive functions.

Here are some practical examples. A commercial truck driver in Colorado holds a state medical marijuana card and uses a licensed dispensary product for pain management. After a random DOT urine test returns positive for marijuana metabolites, the driver provides the card and purchase receipts to the MRO. The MRO cannot accept this as a legitimate medical explanation and must report the result as positive, triggering DOT return-to-duty requirements.

Practical Use Cases

• Commercial Truck Driver: A driver in Colorado holds a state medical marijuana card and uses a licensed dispensary product for pain management. After a random DOT urine test returns positive for marijuana metabolites, the driver provides the card and purchase receipts to the MRO. The MRO cannot accept this as a legitimate medical explanation and must report the result as positive, triggering DOT return-to-duty requirements. 
• Transit Bus Operator: An employee in a safety-sensitive public transit role tests positive after recreational use of state-legal cannabis. The employee submits a physician's recommendation and dispensary records. Under Part 40, these documents are insufficient; the MRO verifies the result as positive because state programs do not meet federal prescription standards.
• Pipeline Maintenance Technician: Following a post-accident test, a technician claims the positive came from legally purchased edibles in a recreational state. Even with proof of state-compliant purchase, the MRO has no authority to overturn the laboratory positive, as marijuana remains incompatible with safety-sensitive duties under federal rules.

Even with proof of state-compliant purchase, the MRO has no authority to overturn the laboratory positive as marijuana remains incompatible with safety-sensitive duties under federal rules.