Patients' inclusion criteria

• Oncologic patients aged 2 months to 17 years (older than 60 days and younger than 18 years),
• High probability of febrile neutropenia during the study period
• Written informed consent from parents and adolescents older than 14 years

Patients' exclusion criteria

• Neutropenia not related to cancer and/or chemotherapy
• Refusal to participate
• Non-French speaking parents/patients older than 11 years old
• Absence of febrile neutropenia or agranulocytosis during the study period (secondary exclusion)

Febrile neutropenia episodes inclusion criteria

• Febrile neutropenia or agranulocytosis defined as:

  • Neutropenia: absolute neutrophils <500 cells/µL or agranulocytosis: absolute neutrophils <100 cells/µL or patients expected to be neutropenic in the next 24 hours due to ongoing chemotherapy
  • body temperature (tympanic or axillary) ≥38°C during at least one hour or a single T ≥38.5°C

• At least 2 weeks after the end of the previous antibiotic treatment for another included episode of febrile neutropenia.

Febrile neutropenia episodes exclusion criteria:

• Severe renal failure (GFR<15 mL/min/1.73 m²)
• Pregnancy
• Inability to obtain the first therapeutic drug monitoring (TDM) result within 72 hours of sampling (e.g. admission before or during public holidays laboratory closure)