What is a MRO – Medical Review Officer?

MRO in the world of drug testing stands for Medical Review Officer. A MRO is a licensed physician who receives and reviews laboratory drug test results and evaluates those results while taking into consideration the donor’s medical history and prescription usage. These physicians are specially trained in substance abuse testing and provide protection for the donor to ensure that a positive drug test result is not due to legitimate prescription usage.


MRO review, while not always required, is very common in employment drug testing in order to protect both the employee and the employer. MRO review is less common when it comes to legal or court ordered testing.

The MRO Review Process

The MRO review process begins when the laboratory has completed the drug testing process and reports their findings (results) to the Medical Review Officer. The Medical Review Officer’s team examine the entire collection process to make sure the correct test panel was performed and that the correct procedures were followed by the collector to make sure that there is no evidence of tampering or foul play that could disqualify the results.

When a drug test is reported positive by the lab, the MRO will then contact the donor to determine if there is a legitimate medical explanation for the positive lab result.  The MRO will ask the donor specific, health history and prescription usage questions and seek to validate any history or prescription information provided by the donor. In some cases. prescription medications or medical treatments can cause a positive lab test result.  In these situations, the MRO will obtain verification of a valid prescription or recent medical treatment and then finalize the drug test result and report the result as negative or positive based on their findings.

Using an MRO to review and interpret the laboratory test results provides a professional, scientific, unbiased, third party review of the results. This protects the donor’s health and medical history from parties that do not have the right to that information and also protects the entire process to insure the integrity of the testing process from collection to the final result being reported.

MRO Review For Employment Drug Testing

MRO review is required for all Department of Transportation (DOT) regulated drug testing. For unregulated testing, or non-DOT testing, MRO review is not required, but is strongly recommended given the protections it offers both the employee and the employer.

MRO Review For Legal/Court Testing

MRO review for court ordered or legal forensic drug testing is not as common. The lack of MRO review provides the court the opportunity to see the raw test results direct from the laboratory. Without MRO review, the determination if a drug test is positive due to prescription medication, medical procedures or illegal use gets placed into the hands of lawyers, judges and juries.


To learn more about what drug testing services are best suited for your needs, please call or text 843-972-3287 or email us.