The diagnosis of Clostridium difficile-associated diarrhea: comparison of Triage C. difficile panel, EIA for Tox A/B and cytotoxin assays

Abstract

This study prospectively compared; Triage(R) C. difficile test (TCT), TechLab C. difficile toxin A-B enzyme immuno-assay (EIA), and cell-culture cytotoxin test (CT). Of the 400 stools tested, 99 were positive by any test with 92, 41 and 58 detected by TCT, EIA and CT, respectively. Culture of discordant samples indicated that 52 contained C. difficile (42 toxigenic, 10 non-toxigenic), 10 contained Clostridium species and 2 had no detectable clostridium isolates. There were 21/42 toxigenic C. difficile isolates from 17 patients whose stools were negative when originally tested by CT. Review of available patient charts indicated that 12/14 did not previously or currently have C. difficile associated diarrhea, whereas 2 patients developed disease within a few days. Compared to CT as the gold standard, the sensitivity and specificity were; 93%, 89% and 66%, 99% for TCT and EIA respectively. The 8 stool samples with Toxin A(-) Toxin B(+) isolates were detected in 8, 4, and 6 samples by TCT, EIA and CT, respectively. In summary, TCT as a screening test allowed reliable reporting for 85% of stools on the day of receipt. For the 15% of stools requiring further testing we recommend the use of CT.