title: Clostridium difficile infection diagnostics - evaluation of the C. DIFF Quik Chek Complete assay, a rapid enzyme immunoassay for detection of toxigenic C. difficile in clinical stool samples.
abstract: Diagnostic testing for Clostridium difficile infection (CDI) has, in recent years, seen the introduction of rapid dual-EIA (enzyme immunoassay) tests combining species-specific glutamate dehydrogenase (GDH) with toxin A/B. In a prospective study, we compared the C. DIFF Quik Chek Complete test to a combination of selective culture (SC) and loop-mediated isothermal amplification (LAMP) of the toxin A gene. Of 419 specimens, 68 were positive in SC including 62 positive in LAMP (14.7%). The combined EIA yielded 82 GDH positives of which 47 were confirmed toxin A/B positive (11%) corresponding to a sensitivity and specificity of 94% for GDH EIA compared to SC and for toxin A/B EIA a sensitivity of 71% and a specificity of 99% compared to LAMP. Twenty different PCR ribotypes were evenly distributed except for UK 081 where only 25% were toxin A/B positive compared to LAMP. We propose a primary use of a combined GDH toxin A/B EIA permitting a sensitive 1-h result of 379 of 419 (90%, all negatives plus GDH and toxin EIA positives) referred specimens. The remaining 10% being GDH positive should be tested for toxin A/B gene on the same day and positive results left to a final decision by the physician.
authors.affiliation: Department of Laboratory Medicine, Molecular Diagnostics, Örebro University Hospital, Örebro, Sweden. karin.johansson11@regionorebrolan.se.
authors.forename: Karin
authors.initials: K
authors.lastname: Johansson
authors.affiliation: Department of Laboratory Medicine, Molecular Diagnostics, Örebro University Hospital, Örebro, Sweden.
authors.forename: Hanna
authors.initials: H
authors.lastname: Karlsson
authors.affiliation: Department of Laboratory Medicine, Clinical Microbiology, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
authors.forename: Torbjörn
authors.initials: T
authors.lastname: Norén
mesh_terms: D000465:Algorithms; D001399:Azure Stains; D001431:Bacteriological Techniques / Q000379:methods; D016360:Clostridioides difficile / Q000302:isolation & purification*; D003015:Clostridium Infections / Q000175:diagnosis*; D003955:Diagnostic Tests, Routine / Q000379:methods*; D005243:Feces / Q000382:microbiology*; D006801:Humans; D007124:Immunoenzyme Techniques / Q000379:methods*; D008751:Methylene Blue; D025202:Molecular Diagnostic Techniques / Q000379:methods; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D013997:Time Factors; D014966:Xanthenes
chemical_list: D001399:Azure Stains; C067461:Diff Quik; D014966:Xanthenes; D008751:Methylene Blue
keywords: 
  Clostridium difficile
  ; diagnostics; glutamate dehydrogenase; toxin A/B EIA