Drug of abuse testing is a process of identification of illegal drugs in blood, urine, saliva and others. The drugs include cocaine, opiates, marijuana, methamphetamine, benzodiazepine, methadone, ecstasy, amphetamine, barbiturates, PCP and others. Drug of abuse testing is a qualitative process and mostly performed in clinical settings. In drug of abuse testing, sample collection is a critical process and requires high integrity. Urine is the most preferable sample for the drug of abuse testing due to the high window of detection and 75% of the clinical settings use urine for testing.