Neutropenic fever is a potentially life-threatening condition that often occurs in cancer patients, particularly those undergoing chemotherapy. It is defined as a single oral temperature of ≥38.3°C (101°F) or a sustained temperature of ≥38.0°C (100.4°F) for over an hour, in the setting of neutropenia (an abnormally low count of neutrophils, a type of white blood cell).