Evaluation of the C.Diff Quik Chek Complete Assay, a New Glutamate Dehydrogenase and A/B Toxin Combination Lateral Flow Assay for Use in Rapid, Simple Diagnosis of Clostridium difficile Disease

Abstract

The diagnosis of Clostridium difficile infection continues to be a challenge for many clinical microbiology laboratories. A new lateral flow assay, the C.Diff Quik Chek Complete assay, which tests for the presence of both glutamate dehydrogenase (GDH) and C. difficile toxins A and B, was evaluated for its ability to diagnose C. difficile disease. The results of this assay were compared to those of both PCR and toxigenic culture. The results showed that this assay allows 88% of specimens to be accurately screened as either positive (both tests positive) or negative (both tests negative) for the presence of toxigenic C. difficile in less than 30 min and with minimal hands-on time. Use of a random-access PCR for the analysis of specimens with discrepant results (one test positive and the other negative) allows the easy, rapid, and highly sensitive (100%; 95% confidence interval [CI], 89.6 to 100%) and specific (99.6%; 95% CI, 97.3 to 99.9%) diagnosis of C. difficile disease. The use of this algorithm would save institutional costs, curtail unnecessary isolation days, reduce the nosocomial transmission of disease, and increase the quality of care for patients.

Loop-Mediated Isothermal Amplification Compared to Real-Time PCR and Enzyme Immunoassay for Toxigenic Clostridium difficile Detection

“…However, the reported rate of falsepositive GDH EIAs approaches 50% (8, 13, 15, 23-25, 30, 32), suggesting that the specificity and PPV of a GDH assay alone could be much lower in other settings. Nonetheless, the high sensitivity reported with this GDH EIA format supports the use of GDH assays as an initial screen, followed by a more specific 2nd test, such as a CCNA, a TC, or a DNA amplification assay, to confirm the presence of toxin A and/or B or their respective genes (23,25,30). The net benefit (i.e., the expense of personnel and supplies versus reimbursement) of performing multiple tests compared to DNA amplification alone remains to be determined, with standalone real-time PCR demonstrating equivalent to superior sensitivity and specificity (13,15,24,32).…”

“…However, considering only the GDH component of the Quik Chek Complete to detect any C. difficile in this study, the calculated sensitivity, specificity, positive predictive value, and negative predictive value were 95.8%, 100%, 100%, and 99.1%, respectively (Table 2). One recent suggestion was that using fresh rather than frozen stool specimens increased the sensitivity of the assay (25); of note, we tested only fresh samples in our study. Interestingly, only three nontoxigenic C. difficile isolates were detected overall in our study versus 21 toxigenic isolates for a "falsepositive" rate of 12.5%.…”

Evaluation of three enzyme immunoassays and a nucleic acid amplification test for the diagnosis of Clostridium difficile-associated diarrhea at a university hospital in Brazil

“…A wide variety of media and differences in isolation protocols, such as the use of shock alcohol and variations in incubation time, are common 5,10 . In this study, we opted for a simple isolation protocol, which would be more applicable for diagnosis when compared with previous methods 17 . It is well known that some strains of C. diffi cile may not grow due to susceptibility to either one or both antibiotics used in the medium 18 .…”

An Unusual Case of Clostridium difficile Infection in Trinidad and Tobago

“…However this test was unable to differentiate if the toxin produced was A, B or both. The test is described to be 87.8% sensitive and 99.4% specific [26].…”