2342. Elimination of Reflexive C. difficile PCR Testing Among Inpatients Resulted in Cost Savings Without Adverse Events

BACKGROUND: Diagnosis of C. difficile infection is imperfect and various algorithms have been proposed. While PCR is sensitive for detecting toxin-carrying C. difficile, it leads to overdiagnoses resulting in antibiotic overuse and potentially unnecessary healthcare costs. METHODS: We performed a study of C. difficile cases after changing the testing protocol from reflexive vs. physician-requested PCR in cases of indeterminant EIA testing (antigen +, toxin −). The study was conducted among inpatient adults at four large hospitals in the southern California area and evaluated two 6-month periods: pre-intervention: (September 5, 2016–March 5, 2017) and post-intervention (3/6/2017–9/6/2017). Only the first C. difficile test during a period per patient was evaluated. Primary outcome was change in number of C. difficile diagnoses. Secondary outcomes included adverse events (missed cases of C. difficile and 30-day readmissions) and cost savings (accounting for PCR, isolation, and treatment costs). RESULTS: A total of 500 EIA indeterminant C. difficile test results were evaluated, 281 pre- and 219 post-intervention. There were no statistically significant differences in demographics, laboratory values (WBC, Cr), or hospital site between the study periods. A PCR was performed in 99.6% (280/281; one not performed due to an inhibitor) and 66% (144/219) in the pre- vs. post-intervention periods (P < 0.01); the PCR was positive in 65% (n = 182 and n = 94, respectively) in both periods. The change in testing strategy resulted in a 49% reduction in PCR testing and 48% fewer C. difficile cases. There were no differences between study periods in 30-day readmissions for all-cause (P = 0.96), GI-related illness (P = 0.93) or C. difficile (P = 0.47), nor in new or recurrent C. difficile cases (P > 0.99). No patient without a PCR and not treated was later diagnosed with C. difficile infection. Each reflexive PCR avoided led to a cost savings of $4,384/patient. CONCLUSION: Diagnostic stewardship is an emerging area that can potentially reduce overdiagnosis and overtreatment of a variety of infectious diseases. Our study showed that changing C. difficile PCR testing among EIA-indeterminant cases from reflexive to requiring a physician order resulted in valuable cost savings without associated adverse events. DISCLOSURES: All authors: No reported disclosures.