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DOT Non-Negative Result: The Process

A non-negative result reported by the laboratory may mean several different things—drugs detected in the specimen, the specimen is adulterated or substituted, or the specimen is invalid for testing. A non-negative result requires that a Medical Review Officer (MRO) must interview the donor and make a test result determination before reporting a result to the employer.

So, what happens when a non-negative result is received by the MRO from the lab? What is the process and how long does it take?

Step 1 – Making Contact

When a non-negative result is reported to the MRO from the lab, the MRO team must establish contact with the donor to conduct an interview.

The MRO must make three attempts to establish contact with the donor in the first 24 hours after receiving the non-negative result from the lab. If the contact attempts are unsuccessful, the MRO staff will ask the designated employer representative (Der) for assistance. The DER is to locate and contact the specimen donor (employee or applicant) and instruct him/her to contact the MRO within 72 hours. If the donor does not contact the MRO within 72 hours of being told to do so, the MRO reports the laboratory non-negative result. If the DER is unable to locate or contact the donor, the MRO must wait 10 days before reporting the non-negative result to the employer.

Step 2 – The Interview

The physician MRO will conduct the telephone interview with the donor. The purpose of the interview is to determine if there is an acceptable medical explanation for the laboratory findings. This is the opportunity for the donor to provide any prescription medication documentation, medical records, or other medical information that explains the drugs that were detected, the specimen adulteration or substitution findings, or why the specimen is invalid for testing. It may take 1-5 days for the MRO to review and validate any medical information and documentation provided by the donor.

Step 3 – Reporting the Result

Once the donor interview has been conducted and any medical explanations have been validated, the MRO team will report the MRO verified result to the employer.

If the MRO determines that there is a valid medical explanation for a laboratory positive drug test, it will be reported as a negative result to the employer.  If there is a medical explanation for a laboratory adulterated, substituted, or invalid test, the MRO will report a canceled test.

If the MRO determines that there is not a valid medical explanation for a laboratory positive, a verified positive result specifying the drug(s) detected will be reported to the DER.  For an adulterated or substituted specimen, the MRO will report a refusal to test. If the invalid result has no medical explanation, the MRO will cancel the test, however, will require another test to be conducted with the urine specimen collection directly observed.

The MRO verified result reported to the employer does NOT include the laboratory report or the donor interview information.

A Note on Turnaround Time

It’s important to know that non-negative results take additional time—both at the laboratory and for the MRO process. Specimens that are reported negative by the laboratory, typically are reported to the employer 1-3 days after specimen collection. Non-negative results (positive, adulterated or substituted, or invalid)  may take up to 10 days after specimen collection for the final reporting to the employer.

Learn more about the Turnaround Time