A two-stage algorithm for Clostridium difficile including PCR: can we replace the toxin EIA?

A two step, three-test algorithm for Clostridium difficile infection (CDI) was reviewed. Stool samples were tested by enzyme immunoassays for C. difficile common antigen glutamate dehydrogenase (G) and toxin A/B (T). Samples with discordant results were tested by polymerase chain reaction detecting the toxin B gene (P). The algorithm quickly identified patients with detectable toxin A/B, whereas a large group of patients excreting toxigenic C. difficile but with toxin A/B production below detection level (G(+)T(-)P(+)) was identified separately. The average white blood cell count in patients with a G(+)T(+) result was higher than in those with a G(+)T(-)P(+) result.