Ferritin is a protein in the body that binds to iron. Ferritin is present mostly in the liver, but also in the bone marrow, spleen and muscles. Most of the iron stored in your body is bound to ferritin. The amount of ferritin in the blood helps your doctor understand how much iron your body is storing.
Normally, ferritin is mainly found inside the cells in your body, with only a small amount in the blood. When there is damage to organs that contain ferritin, and when inflammation is present, ferritin levels can be raised even though the total amount of iron in the body is normal. Ferritin levels may not be particularly helpful if measured in people with liver disease, long-term infections, cancer or autoimmune diseases.