The Xpert™ Clostridium difficile kit is a nucleic acid amplification test indicated after discrepant results from an enzymatic test; was submitted for incorporation in a teaching hospital in Brazil. In order to evaluate the potential for improvement with Xpert™ incorporation, the performance of the available technology (enzymatic test) was assessed using a real word evidence approach. Additionally, the association between enzymatic test results and the agreement to the Infectious Diseases Society of America (IDSA) recommendations for stool test submission (≥ 3 unformed stools in 24 hours without laxatives) for Clostridium difficile were evaluated.

This is a retrospective cohort study conducted at a tertiary teaching hospital. We included all consecutive tested patients that were submitted for enzyme immunoassay – glutamate dehydrogenase (GDH) plus toxin detection from 15 March to 8 May 2018. Data referent to episodes of unformed stools in 24 hours and use of laxatives were recorded. Statistical significance was tested by Fisher Exact test (α = 0.05).

One hundred and thirty-eight consecutive patients were tested: 4 (2.9 percent) were positive for GDH and toxin (group III); 114 (82.6 percent) were negative for both (group I). Twenty (14.5 percent) cases were discrepant, all being positive to GDH and negative for toxin (group II). There were not negative GDH and positive toxin cases. The IDSA guidelines were followed in 33 (28.9%), 3 (15%) and 3(75%) test orders in groups I, II and III, respectively (p = 0.03).

Only a minority of patients had discrepant results in enzymatic tests and would be candidates for the Xpert™ test. The low adherence to IDSA guidelines could explain the low positivity rate of enzymatic tests at the hospital. Considering the uncertainty about the potential of the new test for changing infection control practices, Xpert™ was not recommended for incorporation. Using real world evidence data is important for contextualized health technology studies in hospitals.