Oral fluid (saliva) analysis is increasingly popular as a forensic drug testing matrix because samples can be easily collected, collection is non-invasive, and samples are less susceptible to substitution or adulteration. Saliva drug tests can detect drug usage within a few hours up to 2 days and can be used to test for alcohol, barbiturates, benzodiazepines, cocaine, ecstasy, marijuana (THC), opiates, amphetamines, phencyclidine (PCP), and methamphetamines.