(569) Evaluation of Treatment Incidence of PCR-Positive/Toxin-Negative Clostridioides difficile Infections

Introduction: Multiple tests exist for detection of Clostridioides difficile (C. diff) including toxin enzyme immunoassays (EIA), nucleic acid amplification tests (NAAT), and presence of glutamate dehydrogenase (GDH), however none are suitable to be used individually. Patients with discordant test results, such as PCR positive/toxin negative, are considered colonized and do not require treatment in most cases. In November 2020, Charleston Area Medical Center (CAMC) changed the result reporting of the two-step testing strategy for C. diff. This study examined if the change in reporting of PCR positive/toxin negative results impacted unnecessary treatment of colonized patients.

Methods: In this retrospective chart review cohort study, we included adult patients admitted to CAMC Memorial and General hospitals with C. diff testing results reported as PCR positive/toxin negative four months before and after lab value reporting change in CERNER (November 2020). Patients for this study were identified from an internal microbiology report of patients with C. diff PCR positive/toxin negative lab results. We compared duration of oral vancomycin treatment in the two study groups. Basic descriptive statistics, such as means and standard deviations for continuous variables and proportions and frequencies for categorical variables were used to analyze infant characteristics. Comparisons between groups for categorical variables was performed using contingency with Chi-square analysis or Fisher’s exact, or t-test/Mann-Whitney U to determine statistically significant differences pre and post changes in CERNER lab value reporting.

Results: Of the 135 patients included in the study, 63 patients were included in the pre-intervention group and 72 patients in the post-intervention group. Prior to the change in result reporting, 96.8% of patients received C. diff treatment. After the result reporting change, 11.1% of patients received C. diff treatment.

Conclusions: Since changing the color and wording of C. diff test results at CAMC, the number of colonized patients who received treatment decreased significantly. This minor change to the microbiology reporting system has saved CAMC an estimated $12,400 annually, in addition to limiting treatment to patients with active infections.