Drugs of abuse testing in a psychiatric outpatient service

Screening for drugs of abuse in a psychiatric outpatient population plays an important role in assessing abstinence from drug use, relapse, and in evaluating the patient during the course of treatment. The advantages and limitations of testing urine or other sample matrices such as hair or sweat must be understood. Interpretation of test results is based on the pharmokinetics of the drug as well as assay sensitivity, specifity and the cut-offs used. All positive test results need confirmation testing to verify true positivity, especially when involuntary suspension from a treatment program is being considered.