Ferritin provides important information about the body’s iron stores. While serum iron reflects the iron circulating in the blood at a given moment, ferritin mainly reflects stored reserve iron. That is why ferritin is particularly valuable in detecting early iron deficiency. A person may still have normal hemoglobin while ferritin is already low, indicating that iron stores are shrinking. On the other hand, ferritin does not reflect iron storage alone; it can also rise with infection, inflammation, and certain liver conditions. Because of this, ferritin should always be interpreted together with other laboratory values and the clinical picture. In short, ferritin is a strategic marker of the body’s iron reserve system.