A
ferritin of 5 ng/mL (µg/L) is
markedly low and is strongly consistent with
depleted iron stores / iron deficiency. It may occur before, or together with, iron-deficiency anemia. A ferritin under 15 is highly specific for iron deficiency, and fever or inflammation generally raises ferritin rather than lowering it, so a value of 5 is significant.
WHO ferritin guidance
This result does not by itself explain a fever. The fever still needs its own assessment for an infection or other cause.
What should be checked soon:
- CBC: hemoglobin, MCV, MCH, RDW
- Transferrin saturation, serum iron, TIBC
- Cause of iron loss or poor absorption:
- heavy or prolonged menstrual bleeding
- pregnancy or recent delivery
- low iron intake
- gastrointestinal bleeding, ulcers, hemorrhoids, celiac disease, etc.
- In men and postmenopausal women, unexplained iron deficiency generally needs clinician-led evaluation for GI blood loss.
Treatment commonly involves iron replacement, but the dose, route (oral vs IV), and duration should be decided by the clinician based on hemoglobin, symptoms, tolerance, pregnancy status, and the cause. Do not rely on paracetamol, ondansetron, or injections for this problem.
Seek urgent care if there is breathlessness at rest, chest pain, fainting, black/tarry stools, vomiting blood, severe weakness, very heavy bleeding, or persistent high fever.