Patterns of concordance between hair assays and urinalysis for cocaine: longitudinal analysis of probationers in Pinellas County, Florida.

This chapter reports on a field trial involving the application of hair assays to a probation population. The objectives were to evaluate the general reactions of probation officers and probationers to the collection of hair samples, to compare the outcomes of the hair samples with the outcomes of urinalyses (which the probationers undergo routinely), to note and react to differences in the prevalence as indicated by the two assay types, and to assess the general monitoring potential for hair assays in a correctional setting. In general, hair assays showed an increased capability of detecting cocaine exposure when compared to urinalysis. The detection of cannabis was, however, problematic for hair. The hair assays, using urine as a comparator, appeared to result in several apparent false negatives for cannabinoids. There were no false negatives for cocaine, and an approximately fourfold increase in the detection rate when compared to urine. The collection of hair samples was not difficult and the cooperation of the probationers was quite good. Probation officers appear to prefer the use of hair specimens to urine specimen collection, and appeared enthusiastic about the potential use of hair analysis in their routine monitoring of clients.