Improved screening for benzodiazepine metabolites in urine using the Triage Panel for Drugs of Abuse

Screening for benzodiazepines is an important component of many drug testing programs. Current immunochemical methods are limited by a lack of sensitivity to many of the 35 forms of benzodiazepines available and because the antibodies used are insensitive to the glucuronic acid conjugates that constitute the major metabolites in urine. The Triage Panel for Drugs of Abuse (Biosite Diagnostics), a new screening device, is a competitive immunoassay containing monoclonal antibodies directed against glucuronide metabolites of benzodiazepines. We tested this device on 326 urine specimens, which were also tested by two other immunoassay methods (FPIA and EMIT) and by GC/MS. We found a sensitivity of 97.5% and a specificity of 94.3% for the Triage assay when it was applied to a population in which approximately 50% of the specimens were positive; a distribution of eight different benzodiazepines was found in the positive samples. Other immunoassays performed with lower sensitivity or specificity or both. We found no significant difference between two analysts using the Triage test. We conclude that the Triage method represents a superior method for benzodiazepine screening when compared with other immunoassay methods.