With more than half of the states and some U.S. Territories permitting the use of marijuana to treat specific medical conditions, employers are left to wonder what happens following a positive test result. For the Department of Transportation (DOT), the use of state-authorized marijuana will not be permitted as a valid excuse for a federal drug test. In most cases, employers should utilize the services of a federally licensed Medical Review Officer (MRO) to review laboratory-confirmed positive drug test results before reporting back to the employer. If a plan is not already in place, now is the time to enact one by contacting the MRO, service provider or Third-Party Associate (TPA) to clearly understand the scope of their role and what requirements remain.