Prolonged fever in an adult refers to a fever that is over 38°C at times and has lasted for more than 3 weeks, and routine investigations have not revealed any cause for it. Diagnose common diseases (pneumonia, sinusitis, urinary tract infection) before ordering a large number of tests. Decide on the urgency of tests according to the patient's general condition, risk factors (immunosuppression) and local signs. Repeat history and physical examination before repeating tests.
In a child, preliminary investigations of prolonged fever of unknown origin (FUO) in primary health care are
- ESR, full blood count and CRP
- urinalysis and bacterial culture
- imaging studies (chest x-ray, maxillary sinus imaging).