Abstract Background Hospital-onset Clostridioides difficile infection (CDI) is a significant cause of hospital-acquired infections globally. Overuse and inappropriate testing often lead to false-positive cases classified under the National Healthcare Safety Network criteria for hospital-onset CDI (HO-CDI), despite not representing true infections, leading to unnecessary treatment, prolonged isolation, and increased healthcare costs. This quality improvement project evaluates whether prospective audit and feedback on testing, combined with a diagnostic algorithm, can reduce inappropriate testing and HO-CDI cases.Annual Inpatient Clostridium Difficile Testing and Hospital-Onset Clostridium Difficile Infection CasesAnnual inpatient Clostridioides difficile testing and hospital-onset Clostridioides difficile infection cases from 2022 to 2024. Total tests (bars) and hospital-onset infection cases (line) both declined, with the most significant reduction observed in 2024 following the diagnostic stewardship intervention.Clostridium Difficile Testing and Hospital-Onset Clostridium Difficile Infection Cases Before and After the InterventionComparison of Clostridioides difficile testing and hospital-onset Clostridioides difficile infection cases before and after the implementation of a diagnostic stewardship intervention. The number of tests and hospital-onset infection cases both decreased following the intervention, indicating more appropriate test utilization and lower infection rates. Methods An intervention began in May 2024, involving microbiology laboratory technicians contacting the chief of infectious disease to review the appropriateness of Clostridium difficile (C. diff) testing for samples collected 48-72 hours post-admission. Additionally, a hospital-wide diagnostic algorithm was introduced to guide appropriate testing. Total inpatient C. diff tests before and after the intervention were compared. Percentage reductions and paired t-tests (p 0.05) were used to evaluate changes. The project was IRB-exempt. Results C. diff testing declined steadily, with a 10.36% drop from 2022 to 2023 (p = 0.1476) and a 14.07% drop from 2023 to 2024 (p = 0.0809). HO-CDI cases fell by 2.63% from 2022 to 2023 (p = 0.6742) and 27.03% from 2023 to 2024 (p = 0.0001). After the intervention, testing decreased by 19.60% (p = 0.0581) and hospital-onset CDI by 48.48% (p = 0.0052) compared to pre-intervention. CDI cases as a percentage of tests dropped from 9.51% to 6.09% (35.93% reduction, p = 0.9057), while hospital admissions remained stable. Conclusion The sharper decline in C. diff testing from 2023 to 2024 (14.07% vs. 10.36%) suggests the intervention helped reduce unnecessary testing. Post-intervention, HO-CDI fell by 48.48% (p = 0.0052), while testing dropped by 19.60%, indicating improved test appropriateness rather than under-diagnosis. These results support existing evidence that audit and feedback can reduce over-testing and improve CDI outcomes by aligning testing with guidelines, minimizing unnecessary antibiotics, and isolation. Future research should assess sustaining improvements and refining stewardship to ease reliance on a testing gatekeeper. Disclosures All Authors: No reported disclosures
Akiki et al. (2026) studied this question.