False Negative Results in Clostridium difficile Testing. Issue 1 (December 2016)

• Record Type: Journal Article
• Authors: Murad, Yanal; Perez, Justo; Ybazeta, Gustavo; Mavin, Sarah; Lefebvre, Sebastien; Weese, J.; Rousseau, Joyce; Diaz-Mitoma, Francisco; Nokhbeh, Reza
• Is Part Of: BMC infectious diseases. Volume 16:Issue 1(2016)
• Page Start: 1
• Page End: 6
• Publication Date: 2016-12
• Subjects: Clostridium difficile -- Molecular testing -- False negative; Communicable diseases -- Periodicals; Sexually Transmitted Diseases -- Periodicals; 616.905
• DOI: 10.1186/s12879-016-1741-6
• Languages: English
• ISSNs: 1471-2334

Abstract

Abstract Background Accurate diagnosis ofClostridium difficile infection (CDI) is paramount for patient management. The wrong diagnosis places patients at risk, delays treatment, and/ or contributes to transmission of infection in the healthcare setting. Although amplification of the toxin B gene by polymerase chain reaction (PCR) is a sensitive method for detecting toxigenicC. difficile, false negative results still occur and could impact the diagnosis and treatment of this infection. Methods This study investigated 48 patients that tested negative for toxigenicC. difficile via GeneXpertC. difficile epi test, while simultaneously testing positive for toxigenicC. difficile via stool culture. Fifty discrepant samples were collected over a 15-month period and allC. difficile isolates were characterized by ribotype. Patient charts were reviewed to assess whether discrepant results impacted the treatment course or clinical outcome of affected patients. Results Fifty samples of a total of 2308 samples tested in an acute healthcare facility over a 15-month period had negative PCR and positive stool culture for toxigenicC. difficile. C. difficile isolated from the discrepant samples resulted in diverse ribotyping patterns suggesting they were derived from different strains. The samples belonged to patients who were distributed evenly between age groups and wards in the hospital. In the majority of cases, the false negativeC. difficile test results did not seem to impact the clinical outcome in these patients. Conclusions The PCR limit of detection may impact the results of molecular methods forC. difficile detection. Both clinical and analytical sensitivity ofC. difficile tests should be considered when deciding which diagnostic assay to use, and clinical correlates should be examined carefully before excluding CDI as a cause of disease.