Is Clostridioides difficile toxins detection necessary when the glutamate dehydrogenase enzyme is detected?

Introduction: Clostridioides difficile causes diarrhea and pseudomembranous colitis. Its diagnosis is made with glutamate dehydrogenase (GDH) or toxins A and B detection and is confirmed with nucleic acid amplification tests.

Objective: To define if GDH determination is redundant to that of toxins.

Methods: Retrospective, observational study in diarrheal stools of patients with suspected Clostridioides difficile infection. Toxins and GDH were determined by immunochromatography. Bayesian simulation was performed with likelihood ratios; a p-value < 0.05 was regarded as significant.

Results: 329 GDH and toxin A and B results were analyzed. Clostridioides difficile infection prevalence was 18.2 %. Sensitivity and specificity of the GDH test were 0.90 and 0.89, respectively. Positive likelihood ratio was 8.9, and negative was 0.11.

Conclusions: A negative GDH result considerably reduces the probability of infection but does not rule it out. Clostridioides difficile toxins detection may be necessary in institutions where nucleic acid amplification is not affordable or accessible.