Quantitative urine levels of abusable drugs for clinical purposes

Urine screening by polarized fluorescent immunoassay (PFI), which can quantitate concentrations of drugs of abuse within specific ranges, has recently been developed. It is rapid and inexpensive, so it can be clinically used on a routine basis. Reported here are the urine concentrations of marijuana, cocaine, phencyclidine, and amphetamine metabolites in 790 clinical patients who either sought medical detoxification for a self-diagnosis of addiction, or a counseling and urine testing program with the self-perception that they were occasional, nonaddicted users. Mean urine concentrations of cocaine, phencyclidine, and amphetamine, but not marijuana, metabolites were significantly higher in addicted than nonaddicted patients. Sequential urine tests in addicts progressively demonstrate reduced urine concentrations for as long as several weeks if cessation of usage has occurred. Nonaddicted, occasional users usually produce a negative urine sample within 2 to 3 days. Despite some overlap in urine concentrations between addicted and nonaddicted users at the time of admission for treatment, quantitative urine testing is a valuable adjunct in the clinical diagnosis and treatment of drug abuse.