MULTICENTER EVALUATION OF 4 METHODS FOR CLOSTRIDIUM-DIFFICILE DETECTION - IMMUNOCARD CLOSTRIDIUM-DIFFICILE, CYTOTOXIN ASSAY, CULTURE, AND LATEX AGGLUTINATION

A three-center study was undertaken to compare several test methods fo r the detection of Clostridium difficile, associated toxin, or related markers by using 927 stool specimens, Methods included direct assay o f cytotoxin in stool by tissue culture, C. difficile bacterial culture followed by cytotoxin assay, bacterial culture alone, latex agglutina tion assay, and the ImmunoCard C. difficile test (Meridian Diagnostics , Inc.), The sensitivities, as determined against direct cytotoxin ass ay results, of the ImmunoCard C. difficile and latex agglutination ass ays were 84 and 67%, respectively (92 and 77%, respectively, when adju sted for bacterial culture outcomes), Evaluation for C. difficile-asso ciated disease (CDAD) among 864 patients was based on clinical criteri a for antibiotic-associated diarrhea combined with laboratory evidence of toxin or toxin-producing C. difficile in stool specimens, The sens itivity of each test method for screening of CDAD was as follows: bact erial culture, 95%; culture with cytotoxin assay of isolates, 90%; Imm unoCard C. difficile test, 83%; cytotoxin assay 82%; and latex aggluti nation assay, 67% (P less than or equal to 0.05 versus all other metho ds), The standard deviations of the test sensitivity statistics betwee n study sites were ranked as follows: cytotoxin assay (+/-3.1%) < Immu noCard C. difficile test (+/-5.7%) < latex agglutination assay (+/-12. 3%) < culture (+/-24.7%) < culture with cytotoxin assay (+/-28.0%). Th e data support the use of the ImmunoCard C. difficile test as an adjun ct for the diagnosis of CDAD.