Evaluation of different algorithm schemes in the laboratory diagnosis of Clostridioides difficile

Purpose: Clostridioides difficile infection is a major cause of antibiotic-associated diarrhea, particularly in healthcare settings. This study aims to evaluate the applicability, speed, cost-effectiveness, and diagnostic accuracy of different laboratory algorithm schemes for C. difficile infection in a routine clinical setting. Materials and Methods: A total of 479 stool samples from patients suspected of having C. difficile infection were analyzed using glutamate dehydrogenase enzyme immunoassay, toxin A/B enzyme immunoassay, toxigenic culture, and real-time polymerase chain reaction. The sensitivity, cost-effectiveness and overall diagnostic accuracy of these methods were assessed when applied in different algorithmic sequences. Results: Of the 479 samples, 52 were positive for glutamate dehydrogenase antigen. Polymerase chain reaction exhibited the highest sensitivity, detecting C. difficile in 55.8% of glutamate dehydrogenase -positive samples, followed by toxigenic culture at 25.0%, and toxin A/B enzyme immunoassay at 23.1%. The combination of glutamate dehydrogenase screening followed by polymerase chain reaction was the most effective diagnostic approach, offering both high sensitivity and cost-effectiveness. Conclusion: The study emphasizes the importance of a multi-step diagnostic algorithm, particularly starting with glutamate dehydrogenase screening followed by PCR, to improve the accuracy and cost-effectiveness of C. difficile infection diagnosis. These findings support the need for tailored diagnostic strategies based on laboratory resources and patient population characteristics.