Abbott phencyclidine and barbiturates abused drug assays: evaluation and comparison of ADx FPIA, TDx FPIA, EMIT, and GC/MS methods.

This study evaluated the capability of the Abbott ADx assays to test for phencyclidine (PCP) and barbiturates in urine specimens by comparison to TDx, EMIT, and gas chromatographic/mass spectrometric (GC/MS) methods. Within-run and between-run precision were determined using three control samples (35, 100, and 250 ng/mL PCP; 0.4, 0.6, and 1.0 mg/L secobarbital) tested over a two-week period. Controls were analyzed in both single assay (batch) and multiple assay (combination) modes. Within-run coefficients of variation (CVs) for the three PCP controls were 2.4, 2.6, and 2.2%, respectively; the between-run CVs were 4.0, 3.5, and 2.8%, respectively. The within-run CVs for the three barbiturate controls were 3.0, 2.7, and 2.7%, respectively; the between-run CVs were 5.6, 4.7, and 4.5%, respectively. Fifty specimens not containing PCP or barbiturates, 50 specimens containing PCP, and 50 specimens containing barbiturates were tested by ADx, TDx, EMIT, and GC/MS. The methods compared favorably and no false positive or false negative results were obtained by any immunoassay method for any assay when compared to GC/MS.