title: Comparison of the premier toxin A and B assay and the TOX A/B II assay for diagnosis of Clostridium difficile infection.
abstract: Clostridium difficile causes nosocomial diarrhea and is responsible for complications such as pseudomembranous colitis, megacolon, and perforation. Using 442 stool specimens, we compared the sensitivities and specificities of the Premier toxin A and B (Meridian Bioscience, Inc.) and C. difficile TOX A/B II (TechLab, Inc., Blacksburg, VA) immunoassays in the Virology Department of the Kaiser Permanente Regional Reference Laboratories. The Premier toxin A and B assay demonstrated a higher sensitivity (97.44%) and a higher positive predictive value (79.17%) than the C. difficile TOX A/B II assay (87.18% and 75.56%, respectively), while assay specificities and negative predictive values were similar. We also performed experiments using serially diluted, purified toxin A and B antigens to understand the basis for assay differences. The two assays' toxin A antibodies detected toxin A at comparable levels. Preliminary results indicated that the toxin B antibody in the Premier toxin A and B assay could detect toxin B at a concentration of 125 pg/100 microl, while the toxin B antibody in the C. difficile TOX A/B II assay could not detect toxin B below a concentration of 250 pg/100 microl. Therefore, the Premier toxin A and B assay provides greater sensitivity than the C. difficile TOX A/B II assay, perhaps due to a superior detection ability of its toxin B antibody.
authors.affiliation: Kaiser Permanente Regional Reference Laboratories, North Hollywood, California 91605, USA. Susan.M.Novak@kp.org
authors.forename: Susan M
authors.initials: SM
authors.lastname: Novak-Weekley
authors.forename: Michele H
authors.initials: MH
authors.lastname: Hollingsworth
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000907:Antibodies, Bacterial / Q000097:blood / Q000276:immunology; D001426:Bacterial Proteins / Q000032:analysis* / Q000276:immunology; D001427:Bacterial Toxins / Q000032:analysis* / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D016360:Clostridioides difficile / Q000276:immunology* / Q000302:isolation & purification; D004761:Enterocolitis, Pseudomembranous / Q000175:diagnosis* / Q000382:microbiology; D004768:Enterotoxins / Q000032:analysis* / Q000276:immunology; D005243:Feces / Q000382:microbiology; D006801:Humans; D007118:Immunoassay / Q000379:methods; D007223:Infant; D008875:Middle Aged; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity
chemical_list: D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004768:Enterotoxins; C041348:tcdA protein, Clostridium difficile; C031815:toxB protein, Clostridium difficile