[The problems of rapid diagnosis of Clostridium difficile as causative agent of antibiotic-associated...

This paper compares three common methods for the detection of Clostridium difficile, i.e. latex agglutination, culture and cytotoxic activity. The sensitivity of the latex agglutination test alone is 70%, of the culture 100% and of the cytotoxin test 66%. Specificities are 93, 96 and 100%, respectively. The latex agglutination has positive and negative predictive values of 58 and 96%; the respective values for the culture are 77 and 100%, for the cytotoxin assay 100 and 96%. Whereas all tests are fairly reliable for the exclusion of diarrhea associated to Clostridium difficile (CAD), the positive predictive values of latex agglutination and culture are too low. If one requests two positive test results for proof of CAD, about two third of all cases are detected by any combination of laboratory tests, while the specificity approaches 100%. We recommend that two of the three tests are performed; the choice is influenced by the possibilities of the laboratory.