Fever
A raised body temperature, usually above 38°C — the body's normal response to infection and, less often, to inflammation, medication or other illness. Most fevers are short-lived and viral; a persistent or high fever, or fever with red-flag symptoms, needs assessment.
What it means
Fever is a regulated rise in body temperature driven by the immune system, most commonly in response to infection. It is a symptom, not a disease, and it usually reflects the body doing its job. The causes group into: infection — viral (the great majority of brief fevers), bacterial, and less commonly parasitic or fungal; inflammatory and autoimmune disease — such as lupus or rheumatoid arthritis; medications and vaccines; and, when fever is prolonged and unexplained, less common causes including certain cancers (fever of unknown origin). What matters clinically is less the exact number and more the pattern and company it keeps: how high, how long, and which other symptoms accompany it. Blood tests help distinguish a self-limiting viral illness from something needing treatment.
Common causes
- Viral infection — colds, flu, COVID, gastroenteritis; by far the commonest, usually brief and self-limiting.
- Bacterial infection — urine, chest, skin, throat; may need antibiotics.
- Inflammatory / autoimmune disease — lupus, rheumatoid arthritis, inflammatory bowel disease.
- Medications and vaccines — a recognised, usually short-lived cause.
- Post-travel infections — malaria and others; always mention recent travel.
- Prolonged unexplained fever (fever of unknown origin) — occasionally hidden infection, autoimmune disease, or malignancy such as lymphoma.
Lab work-up approach
A brief fever in an otherwise well adult with obvious viral symptoms usually needs no tests. When fever is high, persistent (beyond about a week), or accompanied by concerning features, a targeted panel helps: full blood count (white cells), CRP and ESR (inflammation), and, where sepsis is a concern, procalcitonin, which rises more with bacterial infection. Urine and other cultures, a chest assessment and, in the right context, malaria testing are guided by the story. A prolonged unexplained fever prompts a broader search including ferritin and imaging. Mediora.AI surfaces the inflammatory and white-cell pattern from your results to help gauge how active the process is; the clinical decision — and any treatment — belongs with your doctor.
Tests Mediora.AI can interpret
Related conditions
Panels to consider
When to see a doctor
Seek urgent care for fever with any red flag: a stiff neck, a rash that does not fade under pressure, severe headache, confusion or drowsiness, difficulty breathing, persistent vomiting, a very high temperature, or fever in someone with a weakened immune system, in early pregnancy, or in a very young infant. See a doctor for fever lasting more than about 3–5 days, fever that keeps returning, or fever after travel to a malaria area. Most other fevers can be managed with rest, fluids and time. Mediora.AI helps read the inflammatory markers; the assessment of a fever is your doctor's.