Drug testing involves the two-part analysis of a biological specimen, typically urine, to determine whether traces of illicit drugs are present in the body. The first part, a screening test, involves a relatively simple analysis using thin-layer chromatography. If the sample tests positive for drugs, a more sophisticated confirmation test employing gas chromatography/mass spectrometry may be performed. In addition to urine analysis, blood and saliva may be tested, and the use of hair sample analysis has become more common. The basic drug testing “panel” includes checks for the presence of amphetamines, tetrahydrocannabinol (cannabinoids, marijuana, hash), cocaine, opiates (heroin, opium, codeine, morphine), and phencyclidine. Additional panels include legal drugs that individuals may be taking with a physician’s prescription, such as opiate pain killers and benzodiazepines tranquilizers. ...