Pathogen ID by mNGS during neutropenic fever

Background: Febrile neutropenia (FN) following chemotherapy is a major cause of morbidity during cancer treatment. The performance of metagenomic next-generation sequencing (mNGS) of circulating cell-free DNA from plasma may be superior to blood culture (BC) diagnostics for identification of causative pathogens. The aim of this study was to validate mNGS (DISQVER test) for the detection of pathogens in hematologic patients with FN. Methods: We collected paired whole blood specimens from central venous catheter and peripheral vein during FN for BC and mNGS testing. We repeated paired sampling at the earliest after 3 days of fever, which was defined as one FN episode. All clinical data were retrospectively reviewed by an infectious disease expert panel. We calculated percent positive agreement (PPA), percent negative agreement (PNA), percent overall agreement (POA), and sensitivity and specificity. Results: We analyzed a total of 98 unselected FN episodes in 61 patients who developed predominantly FN after conditioning therapy for allogeneic (n=22) or autologous (n=21) hematopoietic stem cell transplantation. Success rate of mNGS was 99% (97/98). Positivity rate of mNGS was 43% (42/97) overall and 32% (31/97) excluding viruses compared to 14% (14/98) in BC. PPA, PNA 5 and POA between mNGS and BC were 84.6% (95% CI, 54.6% to 98.1%), 63.1% (51.9% to 73.4%) and 66% (55.7% to 75.3%), respectively. Sensitivity for bacteria or fungi was 40% (28.0% to 52.9%) and 18.5% (9.9% to 30.0%), respectively.