Diagnostic Algorithm for the Rapid and Cost- Effective Detection of Clostridioides difficile Infection: Comparison between C. DIFF QUIK CHEK COMPLETE and VIDAS GDH & Toxin Assay

Abstract

Background: We evaluated the analytical performance and cost-effectiveness of lateral flow immunoassays (LFIAs) in detecting Clostridioides difficile glutamate dehydrogenase (GDH) antigen and toxin A/B, followed by a rapid nucleic acid amplification test (NAAT). Methods: A total of 341 unformed stools were tested using a two-step algorithmic approach with C. DIFF QUIK CHEK COMPLETE (QCC) LFIA (TechLab, USA), followed by Xpert C. difficile NAAT (Xpert). The performance of the QCC assay was compared with that of the VIDAS C. difficile GDH and toxin A/B assay (bioMérieux, France), an enzyme-linked fluorescence immunoassay. The clinical performance and cost-effectiveness of the diagnostic algorithms using the QCC or VIDAS assays were compared to the results obtained using the Xpert assay alone. Results: For GDH and toxin detection, the QCC and VIDAS assays demonstrated an almost perfect agreement, with no significant difference in sensitivity (QCC-GDH, 90.5%; VIDAS-GDH, 91.9%; QCC-toxin, 51.4%; VIDAStoxin, 55.4%) and specificity (QCC-GDH, 92.9%; VIDAS-GDH, 89.1%; QCC-toxin, 100%; VIDAS-toxin, 99.6%), compared to the Xpert. The algorithmic approach (GDH and toxin plus Xpert) increased the sensitivity (QCC, 93.2%; VIDAS, 94.6%) and specificity (QCC, 100%; VIDAS, 99.6%). The algorithmic approach reduced the cost compared to the Xpert alone, and the turnaround time of the QCC was shorter than that of the VIDAS assay. Conclusions: Simultaneous detection of GDH and toxin A/B, using QCC or VIDAS assays showed comparable sensitivity and specificity when followed by the Xpert assay. The QCC assay is preferable in turnaround time and cost, which are important considerations for laboratories handling smaller number of samples.