677. To Treat or Not To Treat: Patients with Clostridioides difficile PCR-positive/Toxin EIA negative Test Results

BACKGROUND: Diagnosis of C. difficile infection is complex; multiple diagnostic algorithms are used attempting to identify infected versus colonized patients. Management of symptomatic patients with PCR+ but toxin EIA- disease is controversial, as symptoms are non-specific. Our facility adopted an algorithm using PCR testing first, followed by EIA toxin testing for positive PCRs, in 9/2019. EIA- patients (who are PCR+) are reported as C. difficile negative by the lab. We compared outcomes of PCR- patients with those PCR+/EIA-. METHODS: We manually reviewed the patient records of all inpatients with reported negative C. difficile results from 9/1/22-11/15/22. Negative results were characterized as either PCR- or PCR+/EIA-. Treatment for a test result was defined as flagyl IV/PO, vancomycin PO, or fidaxomicin given within 7 days of the test (for any reason). We evaluated for repeat C. difficile testing, diagnosis of C. difficile infection (CDI), death in 60 days, and cause of death. We compared characteristics between patients with EIA+ versus negative status using Chi-square or Fisher’s exact testing in SAS 9.4. RESULTS: During the study, 321 inpatients had C. difficile tests performed that were reported negative. Of these, 267 were PCR-, and 54 were PCR+/EIA-. The proportion of patients treated did not differ between these groups (table 1, p=0.672). Of the 57 patients that had a repeat test within 60 days, 5 were classified positive (PCR+/EIA+): 2 from the PCR+/EIA- group and 3 from the PCR- group (p=0.065). One patient from the PCR- group subsequently had CDI diagnosed at another facility. Five patients in the PCR+/EIA- group and 32 in the PCR- group died within 60 days; C. difficile was not implicated in the deaths. [Figure: see text] CONCLUSION: Treatment patterns and clinical outcomes in our facility were similar for patients with C. difficile PCR- and PCR+/EIA- diarrhea, in that few patients went on to develop PCR+/EIA+ disease.. Patients were from inpatient locations including bone marrow and solid organ transplant. Study limitations include sample size, and limited 60 day follow up. These data suggest that patients testing PCR+/EIA- may benefit from observation rather than immediate treatment, as 96% (52/54) may not go on to develop CDI. Our findings have implications for lab reporting and treatment of PCR+/EIA- results. DISCLOSURES: Christopher Doern, PhD, GeneCapture: Stocks/Bonds|Quidel: Advisor/Consultant|Shionogi: Honoraria Michelle Doll, MD, MPH, Molnlycke: Grant/Research Support