Usefulness of simultaneous detection of toxin A and glutamate dehydrogenase for the diagnosis of Clostridium difficile-associated diseases.

The aim of this study was to evaluate an immunoassay (Triage; Biosite Diagnostics, BMD, France) for detecting both a specific antigen of Clostridium difficile (glutamate dehydrogenase [GDH]) and toxin A. Evaluation of the test was carried out in 304 fecal samples from patients suspected of having Clostridium difficile-associated diseases. The results with GDH and toxin A were compared with those of a culture and cytotoxicity assay (toxin B). The prevalence rates for toxin B-positive and culture-positive fecal samples were 11.2% and 25%, respectively. The sensitivity of the Triage immunoassay was 90.8% for GDH and 79.4% for toxin A. A negative result with both toxin A and GDH was very reliably able to eliminate a diagnosis of Clostridium difficile-associated disease (negative predictive value 99.6%). Triage is a very rapid (20 min) and easy-to-perform test. It could be useful for diagnostic purposes and also for detecting nontoxigenic strains in epidemiogical studies.