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False-negative results for bromazepam use observed by the EMIT II Plus benzodiazepine assays
, A.M. Al-Amri, H.S. Ali
Published in
Volume: 25
Issue: 2
Pages: 88 - 91
During our extensive routine analyses of drugs of abuse and other drugs such as benzodiazepines using both immunoassays and gas chromatography-mass spectrometry (GC-MS), we have noticed that the EMIT II benzodiazepine assays for urine samples sometimes gave false-negative results for bromazepam use or abuse. The negative benzodiazepine immunoassays and positive GC-MS results for bromazepam in urine could be explained by the absence (or below the detection limit) of 3-hydroxybromazepam (3HB) and the presence of 2-amino-3-hydroxy-5- bromobenzoylpyridine (AHBBP), which are the two major metabolites of bromazepam. 3HB cross-reacted with the antibody contained in the EMIT II, but AHBBP did not, due to their structural characteristics. To avoid such false-negative results for bromazepam, AHBBP screening by GC-MS is recommended. The false-negative results observed for bromazepam are probably not limited to the EMIT II kit; the same phenomena may be also true for other commercially available kits that are based on immunochemical reactions. © 2007 Japanese Association of Forensic Toxicology.
About the journal
JournalForensic Toxicology