Occasionally, there are cases in which both a DOT pre-employment and return-to-duty negative drug test result is required, prior to the performance of covered duties. Typically, DOT does not require redundant testing. Instead, only the more stringent test need be performed, which is the directly observed return-to-duty drug test. The employer must maintain in the employee’s secure file a memorandum providing details on the use of the negative return-to-duty test as evidence pre-employment testing requirements are being met. For the purposes of MIS reporting, employers should report the results of only the test(s) performed. Do not double-report a single return-to-duty test as both a return-to-duty test and a pre-employment test.