Validity testing of the TDX® cocaine metabolite assay with human specimens obtained after intravenous cocaine administration
Clinical specimens obtained from human subjects after intravenous cocaine administration were analyzed by the TDx® Cocaine Metabolite Assay (TDx) and by GC/MS for benzoylecgonine. The TDx results were significantly correlated with results by GC/MS assay with no evidence of bias in the TDx assay. All cocaine metabolite positive specimens (300 ng/ml) were confirmed by GC/MS. Detection times to the last positive specimen by TDx assay and GC/MS assay for four subjects after a 20-mg intravenous dose of cocaine ranged from 29.3 to 39.1 h and 27.9 to 36.6 h, respectively. Overall, the TDx assay was found to be highly specific and accurate for the detection and measurement of benzoylecgonine in urine.