A confirmed positive drug test reassures all the parties involved in the drug testing process that the reported positive result is an analytical true positive and as such is evidence that the individual has been exposed to the drug. That individual may not be a drug abuser and may have a valid alternative explanation for the positive result. In this context, an analytical true positive result may be a clinical false positive. There are many causes other than illicit drug use which can produce positive analytical results. These include environmental exposure, ingestion of medications containing the drugs or medications which metabolize to the target drugs, and consumption of food products containing the drug. Additional laboratory tests and a thorough medical review will ascertain the source of the drug detected and eliminate misinterpreting a clinical false-positive result to implicate that individual as an illicit drug user.