Validity testing of the TDX® cocaine metabolite assay with human specimens obtained after intravenous cocaine administration

Abstract 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.