Workplace drug testing is generally limited to either a five-drug panel or a ten-drug panel. In 1989 when the Department of Transportation first promulgated regulations for drug testing in the transportation industries, a standard panel of five classes of drugs was defined. These drugs are sometimes still referred to as the "NIDA Five" – named after the original Federal agency involved, the National Institute for Drug Abuse. Now the involved regulatory agency is the Substance Abuse and Mental Health Services Administration (SAMHSA).

     The five drugs included in the five-panel test are: amphetamines, cocaine, marijuana, opiates, and phencyclidine (PCP). For more information about each drug go to the SAMHSA Five section.

     Some companies that do not fall under DOT regulations elect to test for ten different classes of drugs. In addition to the five drugs listed above, the additional drugs include: barbiturates, benzodiazepines, methaqualone, methadone, and propoxyphene. In the past few years additional drugs of abuse and “club drugs” have become popular. Drugs such as the synthetic opiates (hydrocodone, oxycodone, and ocycontin) and ecstasy are popular in some circles. For more information about these and other drugs go to the Drugs of Abuse chart.