Follow up drug testing is performed a period of time after an employee returns to work. This test is usually done in conjunction with a return to work drug test to ensure the employee has not continued to violate any company drug and alcohol policies.

Follow-up testing also has specific guidelines that are followed by companies with safety-sensitive employees that are federally mandated. After a return to work drug test is complete an employee is subject to at least 6 follow up tests within one year’s time after they return to work. The substance abuse professional usually sets the number of tests required.