Evaluation of DRI enzyme immunoassays for drugs-of-abuse screening on the Cobas Mira.

OBJECTIVE

To establish optimal performance parameters (ratios of sample and reagents, reaction time, and distinction of absorbance values between calibrators) on the Roche Cobas Mira analyzer for the evaluation of Diagnostic Reagents Inc enzyme immunoassay reagents for urine screening of amphetamines, cannabinoids, cocaine metabolite, opiates, and phencyclidine.

SETTING

Laboratory in a physician's office.

PRACTICE DESCRIPTION

Two laboratorians analyze a daily average of 25 urine samples for employment screening purposes. PRODUCT COMPARISON: DRI reagents were compared to Syva EMIT reagents.

RESULTS

Within-run and between-run precision at the cutoff concentration for DRI reagents ranged from 1.1% to 1.6% CV and 2.2% to 5.7% CV respectively. Results (positive or negative) using DRI or Syva EMIT reagents were identical for cannabinoids, cocaine metabolite, opiates and PCP. Direct comparison for amphetamines was not possible because of different cutoff concentrations of the 2 reagents systems.

CONCLUSION

DRI reagents are acceptable alternatives to EMIT reagents for the analysis of amphetamines, cannabinoids, cocaine metabolite, opiates and phencyclidine in urine on the Cobas Mira analyzer. Utilization of DRI reagents for more than 12 months demonstrated the reliability of the reagents and allowed cost comparison.

ABBREVIATIONS

DRI = Diagnostic Reagents Inc; EMIT = enzyme multiplied immunoassay technique; d.a.u. = drugs of abuse; PCP = phencyclidine; GC/MS = gas chromatography/mass spectrometry.