Abstract Background Karius testing, a commercially available microbial cell-free DNA assay, has emerged as a new diagnostic tool for clinicians, particularly for management of culture negative infections and in immunocompromised patients. There remains uncertainty regarding the clinical impact of next-generation sequencing in patient management. Figure 1 Methods This was a retrospective multi-site observational cohort study over a five-year period from 2018 to 2023 at a community hospital system. Patients were included if they had a Karius test ordered with results available to treating clinicians during the time period. The primary outcome was a change in clinical management defined as either the addition or removal of antibiotics, based on results from Karius testing. Results 391 patients met inclusion criteria, with 283 (72%) in immunocompetent and 108 (28%) in immunocompromised patients. An infectious diseases (ID) consult was obtained in 355 (91%) cases. Fifty-two percent of Karius tests were positive, with an average of 1.1 pathogens reported. Concordance rate between positive cultures and Karius results was 12%. Pneumonia (24%), fever of unknown origin (FUO) (18%), and endocarditis (17%) were the most common indications for Karius orders (Fig 1). Testing changed management in 19% of all included individuals, and in 18% of immunocompromised patients. Karius testing was most impactful in neutropenic fever and endocarditis with 27% and 22% respectively changing management and least impactful when ordered for joint infection, where 12% resulted in a change in management (Fig 2). Conclusion The Karius test changed antibiotic treatment in 19% of patients. It was most clinically relevant in neutropenic fever and endocarditis management. Even with our sizeable sample population including both immunocompromised and immunocompetent patients across a large, multi-site community hospital system, findings remained consistent compared to other smaller studies. Further investigation would be beneficial to determine how best to incorporate this emerging tool in clinical practice. Disclosures All Authors: No reported disclosures
Read full abstract