Latex agglutination test for detection of Clostridium difficile toxin in stool samples

A total of 163 stool specimens were tested for detection of Clostridium difficile and its toxin by cytotoxicity assay with tissue culture, latex agglutination test, and isolation of the organism. From 33 specimens which were positive for toxin by cytotoxicity, 30 were positive by the latex agglutination test; the organism was isolated from 21. The total number of samples which were positive with the latex agglutination test was 44. The predictive value of a positive latex agglutination result relative to the cytotoxicity test was 68%, and the predictive value of a negative result was 97.5%. The specificity and sensitivity of the latex agglutination test relative to the cytotoxicity assay and the low cost and simple facilities required indicate that the latex agglutination test is a useful procedure for screening for C. difficile toxins, provided that positive latex results are confirmed by cytotoxicity assay.