Evaluating appropriateness and diagnostic stewardship opportunities of multiplex polymerase chain reaction gastrointestinal testing within a hospital system

OBJECTIVE: This single-center, retrospective, observational cohort study evaluates the appropriateness of the BioFire® FilmArray® Gastrointestinal (GI) multiplex PCR panel testing at a community-teaching hospital. METHODS: All adult, hospitalized patients at Prisma Health Richland Hospital with a documented GI multiplex PCR panel from 1 April 2015 through 28 February 2018 were included in the analysis. Inappropriate use of the GI panel was defined as a test obtained without documented diarrhea, greater than 2 days of hospitalization, redundant use with other diagnostic tests (e.g. Clostridioides difficile PCR), or laxative use in the preceding 48 h. Antibiotic use and host variables were compared between groups with positive and negative results. RESULTS: During the study period, 442 GI panels were obtained, among which 268 (61%) were deemed inappropriate. Primary reasons for inappropriate testing were lack of documented diarrhea (n = 92), greater than 2 days of hospitalization (n = 116), having a duplicate C. difficile PCR test ordered (n = 118), or laxative use in the 48 h before testing (n = 36). A total of 141 (32%) GI panels were positive. The most frequently identified pathogens were C. difficile (51.1%, n = 72), Enteropathogenic Escherichia coli (17.7%, n = 25), and Norovirus GI/GII (12.1%, n = 17). Patients with negative GI panel results were initiated on antibiotics significantly less frequently than those with positive GI panels (62.5% versus 80.2%, p < 0.00001). CONCLUSION: Stewardship opportunities exist to optimize the diagnostic application of the GI multiplex PCR panel.