COMPARISON BETWEEN THE CEDIA AND EMIT-II IMMUNOASSAYS FOR THE DETERMINATION OF BENZODIAZEPINES

We evaluated a new, qualitative immunoassay for benzodiazepines in uri ne using CEDIA technology on the Hitachi 747 and compared its performa nce to an immunoassay using EMIT II methodology on the same instrument . A total of 500 urine samples received for routine drug screen analys is were prospectively examined for benzodiazepines by both methods. Sa mples producing positive results by either immunoassay method were ana lyzed by gas chromatography-mass spectrometry (CC-MS). Available medic al records were reviewed for patients whose samples produced discrepan t immunoassay results or that were positive in both immunoassays but n egative by GC-MS. Samples that produced negative results in both immun oassays were not subjected to CC-MS analysis. Therefore, identificatio n of an immunoassay result as a false negative only occurred when the sample produced a positive value in only one of the two immunoassays a nd was confirmed as positive by either CC-MS or medical record review. Following initial immunoassay screening and confirmation by CC-MS, a medical record review and reanalysis of GC-MS data was performed. Afte r this in-depth analysis of the data, the CEDIA method produced 60 tru e-positives, 7 false positives and no false negatives. The EMIT IT met hod produced 47 true positives, 1 false positive, and 13 false negativ es. These differences appear to be due to the CEDIA assay being more s ensitive for detection of lorazepam. (C) 1998 Elsevier Science B.V.