Agreement between urinalysis and self-reported drug use.

One hundred fifty-eight drug users received an interview that included self-reported drug use. Opiate/cocaine use in the prior 48 hours was assessed by urinalysis. Fifty-five subjects received a urine test after the interview and 103 were tested before. Chi-square tests were performed to determine if agreement between self-reported drug use and urine test results was associated with timing of urine testing. The rate of agreement was 58% when the urine test was performed after the interview and 93% when performed before the interview (chi2 = 28.6, p < .001). Conducting urine tests before an interview can increase the accuracy of self-reports.