C. Difficile Diagnostics

There are many different ways of testing for C. difficile infections.  Laboratories which follow a multistep algorithm recognize that a positive toxin result is necessary to define clinical disease. Algorithm testing with GDH antigen or NAAT, followed by an EIA toxin test to confirm the active disease, is considered the best-performing algorithm. An efficient approach is to screen samples simultaneously for GDH and toxins A & B using an assay that includes both targets in one test— the C. DIFF QUIK CHEK COMPLETE^® test

Properly distinguishing between true infections and carriers is crucial to protecting patients from unnecessary treatments. Rapid and accurate identification of toxigenic C. difficile allows for appropriate treatment when needed, allowing patients to recover their health, reconnect with loved ones, and reclaim their quality of life.

What about my “pre-agreed institutional criteria” for stool testing? That’s the first step in my algorithm, right?

While the 2021 ACG guidelines do not recommend NAAT-only testing for CDI, the 2018 IDSA/SHEA Guidelines do allow it with pre-agreed institutional sample criteria (i.e.,≥ 3 loose or unformed stools in ≤ 24 hours with a history of antibiotic exposure). However, the pre-agreed institutional criteria are not part of the testing algorithm and the positive predictive value (PPV) of this approach is lower than that of a two-step algorithm often leading to adverse outcomes.

A 2023 update from SHEA/IDSA/APIC announced a proposed modification to the National Healthcare Safety Network’s (NHSN) C. difficile infection reporting guidelines.  In the past, the last test of record defined a C. difficile infection as a reportable event. The proposed new C. difficile infection event definition includes any positive test and treatment initiated within 2 days of the positive C. difficile test as a reportable event.

Learn More about the C. DIFF QUIK CHEK COMPLETE^® test
Learn More about the C. difficile testing algorithms