Random urine drug tests not always reliable

Random urine drug test results carry a substantial risk for error, according to results of a study done by the Children's Hospital Boston Center for Adolescent Substance Abuse.

Researchers reviewed 710 drug tests that were collected over a three-year period, from 110 patients ages 13 to 21, and compared the results with confirmatory lab tests. (All patients were prior drug users and agreed to random testing as a part of treatment.) Of the 710 drug tests, 480 (68%) were negative and 217 were positive. The positive tests were then categorized as resulting from illicit drug use or legitimate use of prescription or over-the-counter medications. Of the 217 positive tests, 45 (21%) were attributed to legitimate drug use. It was determined that out of the 710 tests, 85 (12%) were susceptible to either positive or negative misinterpretation.

The scientists conclude that given the high potential for misinterpretation, there is no justification for implementation of widespread drug testing programs, unless they are rigorously thorough with well-trained staff to observe sample collection and perform follow-up questioning. (Levy S, Sherritt L, Vaughan, BL, et al: Pediatrics 2007; 119:e843)