Cloned enzyme donor immunoassay (CEDIA) for drugs-of-abuse screening.

Large numbers of specimens (5000-18,000) were screened for amphetamines, barbiturates, cocaine, marijuana, opiates, and phencyclidine by RIA (Roche), Emit II (Syva), and a new immunoassay, CEDIA (cloned enzyme donor immunoassay, Microgenics). All immunoassays performed equivalently for cocaine, opiates, and phencyclidine. All immunoassays detected the same amphetamine/methamphetamine-positive specimens, but all also detected numerous specimens containing cross-reacting sympathomimetic amines. CEDIA detected 100%, Emit II 93%, and RIA 82% of the barbiturate-positive specimens. Emit II and CEDIA detected 86-88% of the specimens found by RIA to be marijuana positive. A subset of specimens was additionally screened by OnLine (Roche) and TDx (Abbott) for amphetamines, cocaine, and marijuana. OnLine and TDx also detected all of the amphetamine-positive specimens and numerous specimens containing cross-reacting sympathomimetic amines. All immunoassays performed equivalently for cocaine, and the four nonisotopic tests detected 86-89% of the marijuana positives found by RIA. Interfering sympathomimetic amine drug compounds can be eliminated by using an oxidizing agent, thus decreasing the number of unconfirmable amphetamine presumptive positives. The CEDIAs for all of the major drugs of abuse are reliable and effective for large-volume urine screening programs.

Method comparison of EMIT 700 and EMIT II with RIA for drug screening.

The EMIT 700 and EMIT II assays for marijuana, cocaine, opiates, barbiturates, and phencyclidine, as performed on a Hitachi 717 Analyzer, were compared with Roche Abuscreen RIA tests for high-volume drug abuse screening. The EMIT II kits offer some advantages over the EMIT 700 kits for testing large work loads. The EMIT II marijuana test in particular exhibits a calibration curve that promises improved ability to separate negative from positive samples due to the increased absorbance rate separation between the negative and cutoff calibrators. Both EMIT formulations are preferable in terms of speed and ease of analysis in comparison with our laboratory's current RIA procedures. Over 50,000 urine samples were screened by EMIT 700 and RIA and by EMIT II and RIA. The performance of both EMIT assays was approximately equivalent to RIA in terms of their ability to detect urine samples that confirmed positive for cocaine and opiates. Both EMIT assays detected approximately 90% of the urine samples screened positive by RIA and confirmed positive for marijuana. Both EMIT assays performed better than RIA in detecting confirmed-positive barbiturate samples.

Method comparison of EMIT II and online with RIA for drug screening.

The newest formulation of the EMIT assay for drugs of abuse, EMIT II, and a new immunoassay, OnLine, using the kinetic interaction of microparticles in solution methodology, were evaluated for marijuana, cocaine, opiates, barbiturates, and phencyclidine. Both types of immunoassays were performed on an Hitachi 717 analyzer. Calibration curves, the degree of separation between negative and cutoff calibrators, precision, probability of carryover from positive to negative samples, and overall ease and speed of analysis were evaluated. EMIT II and OnLine were compared with RIA tests for the five drugs to determine each assay's ability to detect samples which confirm positive by GC/MS. The RIA and OnLine marijuana tests detected > 99% of confirmed positive samples while EMIT II detected about 90%. All three immunoassays performed equivalently for cocaine and opiates, each assay detecting at least 98% of positives. Barbiturates showed the greatest disparity with OnLine detecting 96%, EMIT II 85%, and RIA 79% of confirmed positive samples. Too few phencyclidine positive samples were detected for a method comparison study. The fully automated EMIT II and OnLine assays are preferable for a variety of reasons to our laboratory's current semi-automated RIA tests for large volume urine testing. The immunoassays offer comparable performance for some drugs but not for others.

Enzyme immunoassay, kinetic microparticle immunoassay, radioimmunoassay, and fluorescence polarization immunoassay compared for drugs-of-abuse screening.

The newest formulation of the Syva EMIT assay for drugs of abuse, EMIT II, and a new immunoassay, OnLine (Roche), utilizing the kinetic interaction of microparticles in solution (KIMS) methodology, RIA tests, and TDx fluorescence polarization immunoassay (FPIA) procedures were compared for marijuana, cocaine, opiates, and barbiturates. Both EMIT II and OnLine immunoassays were performed with a Hitachi 717 analyzer. Calibration curves, the degree of separation between negative and cutoff calibrators, precision, likelihood of carryover from positive to negative samples, and overall ease and speed of analysis were evaluated. RIA and OnLine detected 99% of gas chromatography/mass spectrometry (GC/MS)-confirmed marijuana samples; TDx, 95%; and EMIT II, 88%. All four immunoassays detected approximately 99% of confirmed cocaine-positive urines. RIA, OnLine, and TDx all detected 100% of opiate-confirmed samples; EMIT II, 97%. Barbiturate assays exhibited the greatest disparity, with OnLine and TDx detecting 100% of confirmed positives; EMIT II, 88%; and RIA, 78%. For a variety of reasons, we prefer the fully automated EMIT II and OnLine assays for high-volume urine testing, in comparison with our laboratory's semiautomated RIA tests and the limited-throughput TDx system. The four immunoassays investigated delivered comparable performance in terms of detection rates for GC/MS-confirmed positives for some drugs but not for others.