Improved CEDIA® Benzodiazepine Assay Eliminates Sertraline Crossreactivity

Initial experiments demonstrated that the original CEDIA (cloned enzyme donor immunoassay) benzodiazepine assay crossreacted with sertraline and sertraline metabolites. In response to this phenomenon, Boehringer Mannheim Corporation developed an improved CEDIA benzodiazepine assay in order to eliminate sertraline crossreactivity. The improved CEDIA assay was evaluated against the original CEDIA product, EMIT II (enzyme multiplied immunoassay technique) benzodiazepine assay, and electron capture negative chemical ionization (ECNCI) gas chromatography-mass spectrometry (GC-MS). Five hundred and thirty-one urine drug screens were tested by the immunoassays. Sensitivity and specificity of these immunoassays for the 5-aryl-7-chloro-1,4-benzodiazepine compounds were 92 and 98%, respectively, for the improved CEDIA assay; 92 and 93%, respectively, for the current CEDIA assay; and 87 and 98%, respectively, for EMIT II. The improved CEDIA assay performed almost identically to the EMIT II assay, both of which had a significant advantage over the original CEDIA product, which was subject to crossreactivity because of sertraline metabolites. The α3-hydroxy ketone metabolites of sertraline are identified in human urine specimens for the first time using ECNCI GC-MS.