The MRO is a physician who needs to have knowledge of drug abuse disorders, pharmacology and toxicology, laboratory techniques for screening and confirmation, forensic collection techniques, and the relevant rules and regulations regarding drug testing. The MRO has several specific responsibilities; these include the interpretation of laboratory test results and the consideration of alternative medical explanations to explain positive tests. The MRO must also prepare a complete and legible written record regarding the reporting of positive results. A broader role may include policy consultation, assessment and action on suspicious results, the preliminary assessment of those who test positive, and return-to-work evaluations. This position offers the opportunity to be in the forefront of current drug policies and an agent of change to reduce drug abuse and its consequences in the United States. 8 references (Author abstract modified)