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1088. Ultrasensitive Detection of C. difficile Toxins in Stool Using Single Molecule Counting Technology: A Multicenter Study for Evaluation of Clinical Performance

BACKGROUND: Commercially available tests for Clostridium difficile infection (CDI) make test selection by the laboratory difficult due to the following unsatisfactory characteristics: long turnaround time, poor sensitivity, and/or poor specificity. The Singulex Clarity(®) C. diff toxins A/B assay (i...

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Detalles Bibliográficos
Autores principales: Young, Stephen, Mills, Ray, Griego-Fullbright, Christen, Wagner, Aaron, Herding, Emily, Nordberg, Vickie, Friedland, Emily, Bartolome, Amelita, Almazan, Anna, Tam, Stanley, Biscocho, Sheryl, Abusali, Salina, Sandlund, Johanna, Estis, Joel, Bishop, Jeffrey, Hansen, Glen
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Oxford University Press 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6255500/
http://dx.doi.org/10.1093/ofid/ofy210.923
Descripción
Sumario:BACKGROUND: Commercially available tests for Clostridium difficile infection (CDI) make test selection by the laboratory difficult due to the following unsatisfactory characteristics: long turnaround time, poor sensitivity, and/or poor specificity. The Singulex Clarity(®) C. diff toxins A/B assay (in development) is a rapid and automated immunoassay for the detection of C. difficile toxins A and B in stool, with analytical limits of detection for toxins A and B at 2.0 and 0.7 pg/mL, respectively. In this multicenter study, the clinical performance of the Singulex Clarity C. diff toxins A/B assay was compared with standalone PCR, a multistep algorithm with enzyme immunoassay (EIA) and PCR, and cell cytotoxicity neutralization assay (CCNA). METHODS: Fresh samples from 267 subjects with suspected CDI were tested at two sites (Minneapolis Medical Research Foundation and TriCore Reference Laboratories) with the Singulex Clarity assay, PCR (Xpert(®)C. difficile), and EIA (C. Diff Quik Chek Complete(®)) for GDH and toxin testing. The performance of the assays and multistep algorithms were evaluated against CCNA (Microbiology Specialists, Inc.). RESULTS: The overall CDI prevalence was 15.7%. The Singulex Clarity C. diff toxins A/B assay had 90.5% sensitivity and 96.0% specificity, with a 98.2% negative predictive value when compared with CCNA, and the Clarity assay’s AuROC was 0.9534. PCR had 90.5% sensitivity and 91.1% specificity. Compared with CCNA, the toxin EIA had 47.6% sensitivity and 100% specificity. Testing with a multistep algorithm using EIA with discordant results reflexed to PCR resulted in 85.7% sensitivity and 94.7% specificity. CONCLUSION: The ultrasensitive Singulex Clarity C. diff toxins A/B assay is equivalent to the sensitivity of PCR while providing higher specificity. Compared with a multistep algorithm, the Clarity assay provides higher sensitivity and specificity while providing faster time-to-result in a simpler-to-understand, one-step reporting structure, allowing for a standalone, single-step solution for detection of C. difficile toxins in patients with suspected CDI. DISCLOSURES: E. Friedland, Singulex, Inc.: Employee, Salary. A. Bartolome, Singulex, Inc.: Employee, Salary. A. Almazan, Singulex, Inc.: Employee, Salary. S. Tam, Singulex, Inc.: Employee, Salary. S. Biscocho, Singulex, Inc.: Employee, Salary. S. Abusali, Singulex, Inc.: Employee, Salary. J. Sandlund, Singulex, Inc.: Employee, Salary. J. Estis, Singulex, Inc.: Employee, Salary. J. Bishop, Singulex, Inc.: Employee, Salary.