B-047 A Rapid Host-Response Test Supports Antimicrobial Stewardship at a Micro-Hospital Emergency Department

Background The management of patients with suspected infections requires identification of the infectious etiology to determine appropriate use of antibiotics. However, differentiating viral from bacterial infection (and co-infection) is often challenging as clinical presentations can be similar and existing diagnostics sometimes fail to identify a clinically relevant pathogen. A host-response test (MeMed BV®, MMBV) that relies on computational integration of three proteins (TRAIL, IP-10 and CRP) measured from blood or serum has demonstrated high diagnostic performance for differentiating bacterial from viral infections, with a negative predictive value >95% across multiple studies. This report evaluates real-world use of MMBV at a micro-hospital Emergency Department (ED) and associated antibiotic prescribing. Methods The study is a retrospective analysis of real-world data collected between January and June 2023. MMBV was ordered by providers at a micro-hospital ED in Tucson, AZ at provider discretion as part of routine care. Prescription among cases with MMBV score <35 was analyzed. This cutoff is indicated by the manufacturer to indicate a viral or other non-bacterial etiology. If an antibiotic was prescribed, the authors conducted a chart review to adjudicate whether the prescription was warranted. Results Data was evaluated between January and June 2023; 116 MMBV tests were ordered by six providers. Most tests (81.9% (95%CI: ±7.0%)) had an MMBV score <35 (mean score 11.3 with standard deviation 10.8). Among these, 92.6% (95%CI: ±5.3%) of cases with viral results were not prescribed antibiotics. MMBV use increased throughout the study period from 12 tests in the first month to 25 in the last month (r = 0.88; p<0.001). There were seven cases where providers chose to prescribe despite a viral MMBV result. Upon chart review, 2/7 were unwarranted prescriptions. Conclusions In the emergency settings, integrating MMBV can effectively guide clinical decision-making, potentially reducing unnecessary antibiotic use. Further research in diverse healthcare settings is needed to validate these findings.