Skip to Content

fever of unknown origin


Definition: the presence of fever (temperature >101°F or 38.3°C) of unknown cause after intensive investigation. Exact criteria for use of term vary, especially regarding duration of fever and extent of clinical investigation; generally a duration of longer than 1 week (some authors require 2–3 weeks) and thorough inpatient investigation or at least three outpatient visits, including a careful history, physical examination, and laboratory tests such as cultures, serologic studies, and invasive procedures for biopsy and/or culture, as indicated by clinical clues or epidemiologic considerations.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

© Copyright 2018 Wolters Kluwer. All Rights Reserved. Review date: Sep 19, 2016.