Febrile neutropenia (FN) following chemotherapy is a major cause of morbidity requiring urgent use of broad-spectrum antibiotics. Blood culture (BC) is a standard diagnostic method for FN but sensitivity of pathogen detection is low. Timely identification of causative pathogens using metagenomic next-generation sequencing (mNGS) of circulating cell-free DNA (cfDNA) from plasma could reduce morbidity and costs by enabling early-targeted antimicrobial therapy. The aim of this study is to establish mNGS (DISQVER) for the detection of pathogens within 24h in immunocompromised haematological patients with FN