The DOT regulation 49 CFR section 40.153, provides the requirement for an MRO to notify an employee of their right to a test of the split specimen for a non-negative laboratory confirmed result. Specifically, section 40.153(b) states, “You must inform the employee that he or she has 72 hours from the time you provide this notification to him or her to request a test of the split specimen.” Note however the MRO has broad discretion to all the retest to be requested after the 72-hour period has elapsed.
