Identification procedures can identify active criminals and persons needing drug abuse treatment and health care and can monitor community trends in drug use. Methods of identification include offenders' self-reports, criminal justice records, urinalysis tests, and radioimmunoassay of hair (RIAH). In a criminal justice setting, urine testing is the most feasible and accurate method now available for screening large numbers of offenders for drug use. Self-report and record information can be effectively used to verify and extend information about the seriousness of use in persons who test positive. The newer RIAH methods offer promise for determining patterns of drug use over time if the method is valid, can be standardized, and gains acceptance from the scientific and judicial communities. Tables and 46 reference notes