Substituted, adulterated, and invalid specimens

Identification and handling of substituted, adulterated, and invalid specimens; refusals to test; required follow-up testing under direct observation.

A commercial driver is notified by the Medical Review Officer (MRO) that their recent urine drug test result was reported by the laboratory as an "Invalid Result." The MRO and the laboratory certifying scientist have already conferred and agreed that no further testing of the primary specimen is necessary. During the interview, the driver denies any attempt to tamper with the specimen but is unable to provide a medical explanation or a valid prescription that could account for the laboratory's findings. What is the MRO's most appropriate next step?

A.Report the test to the employer as a refusal to test because the driver failed to provide a valid specimen and lacks a legitimate medical explanation.

B.Cancel the test and report to the employer that no further action is required unless a negative result is specifically needed for a pre-employment or return-to-duty event.

C.Cancel the test and direct the employer to conduct an immediate recollection under direct observation, recommending the use of an alternate specimen type if practicable.

D.Refer the driver for a medical evaluation by a licensed physician with expertise in the issues raised to determine if a physiological condition exists before reporting the result.