ELISA detection of clonazepam and 7-aminoclonazepam in whole blood and urine

The ability of five commercially available enzyme-linked immunosorbent assay (ELISA) benzodiazepines to detect clonazepam and 7-aminoclonazepam in blood and urine was investigated. To determine the cross-reactivity of various ELISA assays, drug free blood and urine were fortified with clonazepam and 7-aminoflunitrazepam at concentrations of 1, 2.5, 5, 10, and 25microg/dl. The cross-reactivity, with respect to oxazepam, for clonazepam was 16, 37, 80, 93, and 109% with Immunalysis, Diagnostix, Neogen, OraSure, and Cozart, respectively; for 7-aminoclonazepam, none of the five ELISA assays showed any cross-reactivity above 10%.