When should Ferritin be retested?

Ferritin retesting should be guided by the clinical context. Ferritin reflects body iron stores and is used to diagnose and monitor iron deficiency or overload. In iron deficiency anemia, retesting is typically recommended 3–4 weeks after starting oral iron supplementation to assess response; for intravenous iron, 2–4 weeks post-infusion. In suspected iron overload (e.g., hereditary hemochromatosis), serial ferritin measurements help guide phlebotomy frequency. After significant blood loss (surgery, donation, heavy menstruation), retesting after 3–6 months may be appropriate. Because ferritin is an acute-phase reactant, concurrent CRP measurement is advised to rule out inflammation-driven elevation. Reference ranges vary by lab and population. Direct-to-consumer DNA tests for iron-related genes (e.g., HFE) do not replace ferritin measurement. The evidence for retesting intervals is based on clinical guidelines and is strong (human-strong). Without a specific clinical scenario, a universal retesting schedule cannot be given. Always interpret ferritin in the context of full iron panel (serum iron, TIBC, transferrin saturation) and clinical history.