The development of targeted therapies and intensive protocols in oncohaematology has improved the survival of patients with haematological malignancies. The increase in the number of patients treated and their life expectancy has been accompanied by an increase in the incidence of infectious complications secondary to the immunosuppression induced by these therapies. Febrile neutropenia (NF) is a complication that occurs in approximately 10% to 15% of patients treated for solid tumours and up to 100% of patients treated for haematological malignancies, particularly after bone marrow and/or haematopoietic stem cell transplantation. In 25% to 30% of cases, NF leads to serious complications. The vast majority of NF cases are caused by microbial infections (bacteria, viruses, fungi, parasites, etc.), which can progress to severe sepsis or septic shock if appropriate treatment is not initiated rapidly (introduction of anti-infective molecules and implementation of associated procedures). If no pathogen is identified during the management of the most severe patients, the prognosis is poor, with a mortality rate of 10%. The performance of diagnostic strategies is therefore an important factor in improving the prognosis of these patients. To date, the reference diagnosis of microorganisms is based on blood cultures, blood Polymerase Chain Reaction (PCR), β-D-glucan and aspergillosis serology. Identifying the pathogens responsible for NF from a blood sample without an a priori hypothesis and in an optimised timeframe could allow earlier treatment of high-risk NF with implications for management (possible modification of antimicrobial and/or immunosuppressive treatment). The aim of this study is to evaluate the performance of the mNGS-DISQVER® tool in diagnosing pathogenic microorganisms from blood samples collected from patients being managed for high-risk NF.