Interviews, urinalysis, and hair assay were conducted with eighty-eight juvenile arrestees in Cleveland over a two-month period. Hair assay revealed that fifty of the eighty-eight subjects (56.8%) had used cocaine; concentration levels were generally moderate to high. In sharp contrast, urinalysis results identified only seven subjects (8%) as having recently used cocaine. Crosstabulations of urinalysis and sectioned hair assay results indicate that the two detection methods are in greatest concordance for subjects who were heavy users of cocaine and who used cocaine in the last thirty days (as determined by hair assay). Even for these subjects, however, concordance is modest. The data show that self-reports of drug use yield severe underestimates of the prevalence of cocaine use in this population. Implications of the general lack of concordance of the two testing methods are discussed, especially in terms of intervention.
Collecting daily self-reports of injection drug use via automated telephone interviewing