Comparison of the ToxA test with cytotoxicity assay and culture for the detection of Clostridium difficile-associated diarrhoea disease.

Stool samples (355 from 350 patients) were examined in a new commercial assay, the ToxA test, for the rapid diagnosis of Clostridium difficile-associated diarrhoea. The results were compared with direct assay of cytotoxin in McCoy cell tissue culture, and detection of toxigenic C. difficile by culture and cytotoxin testing of isolates. Discordant results were resolved by consultation of clinical records. Test sensitivities were 84.6% for the ToxA test, 78.5% for the direct cytotoxicity assay and 95.4% for culture. The specificity was 100% for all the tests. The ToxA test is a rapid and reliable alternative for the detection of toxigenic C. difficile where tissue culture facilities are unavailable.