Workplace Drug Testing—Prevalence of Positive Test Results, Most Common Substances, and Importance of Medical Review

Abstract Recent data indicate that the use of controlled substances is increasing in working life, which can negatively affect work environment, performance, and safety. Many employers have an alcohol and drug policy that describes routines for preventive measures and early detection of illicit drug use. This often includes drug tests that provide objective information about recent use, and can be done routinely, randomly, and on suspicion. For some substances, however, a positive drug test may also result from prescription as