Stool test for C. difficile toxins A and B
Stool PCR/NAAT test for C. difficile toxin genes
Stool GDH antigen test
Multistep stool testing algorithm using GDH plus toxin assay, with PCR/NAAT as confirmation if needed
Test only unformed stool samples
Colonoscopy or flexible sigmoidoscopy if stool tests are inconclusive and suspicion remains high
Imaging such as abdominal CT if severe disease or complications are suspected