Evaluation of the diagnostic algorithm consisting of enzyme immunoassay for toxins and polymerase chain reaction, for the diagnosis of Clostridium difficile-associated diarrhoea

Abstract A total of 1631 stool specimens were tested for Clostridium difficile toxins A and B using an enzyme immunoassay (EIA). C. difficile toxin was detected in 191 (11.7%, 191/1631) cases by EIA. Among the remaining 1440 cases, 102 cases in patients with either antibiotic-associated diarrhoea or hospitalized patients with unexplained leukocytosis (> 15,000/mm3) and fever (≥ 38°C) even though they did not meet the criteria for diarrhoea, were further assessed using a polymerase chain reaction (PCR) for the toxin B gene (tcdB). Thirty-four cases were tcdB-positive (33.3%, 34/102). A total of 225 cases (13.8%, 225/1631) had a stool test result positive for C. difficile toxins. Among these, 145 cases were diagnosed with C. difficile-associated diarrhoea (CDAD): 80.7% (117/145) using the EIA and 19.3% (28/145) using the PCR. In our study, the 2-test algorithm including EIA-toxin assay and PCR test made a more accurate diagnosis of CDAD. Furthermore, the application of clinical situations may be effective in the selection of patients who need confirmatory testing.