The Validity of Injection Drug Users Self-Reported Use of Opiates and Cocaine

In a study examining the correspondence between self-reported drug use and drug urinalysis, 128 injection drug users (IDUs), who were subjects in an AIDS prevention research project, were asked to provide urine samples, which would be tested for the presence of the metabolites of opiates and cocaine. Ninety-five IDUs provided samples for testing. Of these, twenty IDUs (21.1%) who reported abstinence from opiates and cocaine for the six months prior to the completion of a follow-up questionnaire had their claims contradicted by urinalysis results. Logit regression analyses revealed that IDUs whose primary drug of choice was both crack and injected cocaine and those who were black were significantly more likely to have misrepresented their current drug use status than other groups. The implications of these findings are discussed.