For regulated drug testing, such as that required by the Department of Transportation (DOT), five illicit drugs are mandated, including amphetamines, THC, cocaine, opiates, and phencyclidine. SAMHSA guidelines also specify cutoff levels for each of the drugs. Many private employers are not limited in the number of substances that can be tested for. Additional drugs may include barbiturates, benzodiazepines, and hallucinogens, among others. For private employers, cut-off levels are determined by state law, the nature of the company, and company culture. Some mandatory state laws also exist that allow for specific testing.
