Status of drugs-of-abuse testing in urine under blind conditions: an AACC study.

We report results of a blind study designed to determine the accuracy of drugs-of-abuse testing in urine as done in 31 laboratories across the United States. The drugs studied were amphetamines, cannabinoids, cocaine, opiates, and phencyclidine. These laboratories confirmed all positive drug results with a different analytical method. Ten urine samples were sent to each laboratory, which resulted in 1486 trials. There were no false-positive results. The overall accuracy rate was 97%. Our study demonstrates that urine drug testing can be accurate when performed by qualified staff, using up-to-date screening and confirmation methods, appropriate quality-assurance measures, and a chain of custody.