The ferritin test is ordered to see how much iron your body has stored for future use. The test is done, usually with an iron test and the TIBC, to learn about iron levels in your blood. Ferritin is the best test for iron deficiency and a very good test for iron overload.

If a blood count indicates that your hemoglobin and hematocrit are low, and especially if your red cells are microcytic and hypochromic, iron deficiency is the likely cause of the anemia. Ferritin and other iron tests can be used to confirm the diagnosis.

The test also may be ordered when your doctor suspects that you have iron overload. This may be caused by hemochromatosis or hemosiderosis.

Ferritin levels are low in patients with iron deficiency.

Ferritin levels are high in those with hemochromatosis, a genetic disease in which too much iron is absorbed. However, ferritin may also be increased in patients with inflammation, liver disease, and some types of cancer, and in patients who have had multiple transfusions.

Ferritin is normally found mainly inside of cells, with only a small amount in the blood. When there is damage to organs that contain ferritin (especially the liver, spleen, and bone marrow), ferritin levels can become elevated even though the total amount of iron in the body is normal. Ferritin levels may not be particularly helpful in persons with liver disease, chronic infections, cancers, or autoimmune diseases (which are all associated with organ damage).