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Cloned Enzyme Donor Immunoassay (CEDIA ... - Clinical Chemistry

Cloned Enzyme Donor Immunoassay (CEDIA ... - Clinical Chemistry

Cloned Enzyme Donor Immunoassay (CEDIA ... - Clinical

CLIN. CHEM. 41/1, 92-98 (1995) #{149} Drug Monitoring and Toxicology Cloned Enzyme Donor Immunoassay (CEDIA) for Drugs-of-Abuse Screening David A. Armbruster,’ Edward C. Hubster, Melvin S. Kaufman, and Monica K. Ramon Large numbersofspecimens(5000-18 000) were screened for amphetamines,barbiturates, cocaine,manjuana,opiates, and phencyclidine by RIA (Roche),EmitII(Syva), and a new immunoassay,CEDIA (clonedenzyme donorimmunoassay, Microgenics). Allimmunoassaysperformedequivalently for cocaine, opiates, and phencydidine. All immunoassaysdetected the same amphetamine/methamphetamine-positive specimens,but all also detected numerousspecimenscontainingcross-reacting sympathomimetic amines.CEDL detected 100%, Emit1193%, and RIA 82% ofthebarbituratepositive specimens. EmitIIand CEDIA detected86-88% of the specimensfound by RIA to be manjuana positive. A subset of specimens was additionally screened by OnUne (Roche) and TDx (Abbott) for amphetamines, cocaine, and marijuana. OnLine arid 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% ofthe marijuana positives foundby AlA. 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. Indexing Terms: marijuana/cocaine/opiates/amphe famines/barbit urates/phencyclidine/intermethod comparison/urine Testing urine specimens for drugs of abuse is routinely performed by private industry in workplace drug-testing programs; such testing is mandatory for federal employees. A two-tiered approach is used: All specimens are screened with an immunoassay and the screen-presumptive positives are confirmed by gas chromatography-mass spectrometry (GC-MS).2 The screening test detects the presence of drug and (or) drug metabolite(s) at or above a stated administrative cutoff concentration, and the GC-MS procedures, using separate cutoff values, specifically confirm the presence of the drug. Screening immunoassays are ideally simple, rapid, inexpensive, and capable of automation for large-volume testing. Immunoassays must be accurate Armstrong Laboratory Drug Testing Division, Human Systems Center (AFMC), 2601 West Road, Suite 1, Brooks AFB, TX 78235- 3219. 1 Corresponding author. Fax 210-536-3219. 2Nonstandard abbreviations: GC-MS, gas chromatographymass spectrometry; DOD, Department of Defense; EIA, enzyme immunoassay; and CEDIA, cloned enzyme donor immunoassay. The opinions expressed herein are those of the authors alone and do not necessarily reflect the views of the Department of Defense or of the US Air Force. Received May 31, 1994; accepted October 7, 1994. 92 CLINICALCHEMISTRY,Vol.41, No. 1, 1995 and precise to detect the majority of positive specimens and be reliable to serve as an effective deterrent of drug abuse. We previously evaluated the most commonly used screening tests, including the most recent enzyme immunoassay (EIA) from Syva, Emit II, and a new family of screening tests, Roche’s OnLine assays, based on the kinetic interaction of microparticles in solution (1-3); our purpose was to determine whether these nonisotopic assays would be suitable replacements for the RIA tests currently required by the Department of Defense (DOD) for the military drug-testing program. Another family of immunoassays-based on the cloned enzyme donor iimnunoassay (CEDJA) methodolo-has recently been developed by Microgenics Corporation, and we report here our experience with them. We screened many thousands of specimens for amphetamines, barbiturates, cocaine, marijuana, opiates, and phencycidine, using our routine RJA tests, Emit II, and CEDIA. All specimens that gave positive results by these assays (“presumptive positive”) were tested by GC-MS for confirmation. Most of the specimens screening positive for marijuana, cocaine, and amphetamines were also tested with the OnLine tests and the Abbott TDx fluorescence polarization immunoassay. Materials and Methods Immunoassay Screen Procedure Batches of 200 urine specimens submitted to our laboratory from Air Force units in this country and around the world were tested by routine RIA procedures in accordance with the DOD drug-testing program. Each batch was analyzed for marijuana, cocaine, and a third drug-either amphetamines, barbiturates, opiates, or phencycidine, the selection rotating monthly. After allquots were released from the forensic chain of custody, they were analyzed for the same drugs with a Hitachi 717 analyzer (Boehringer Mannheim, Indianapolis, IN) and Emit II and CEDIA reagents. Aliquots were tested for the same drugs with both types of nonisotopic tests at the same time. Presumptive positives detected by any immunoassay were submitted for GC-MS confirmation. Because of the impracticality of screening all specimens by five different immunoassays, only the presumptive positives detected by RIA, Emit II, or CEDIA were tested with OnLine and TDx assays. DOD screening immunoassay and GC-MS cutoff values are listed in Table 1. Note that some DOD screen cutoffs differ from those mandated by the Department of Health and Human Services National Laboratory Certification Program.

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