Serum ferritin levels are measured in medical laboratories as part of the iron studies workup for iron-deficiency anemia. They are measured in nanograms per milliliter (ng/mL) or micrograms per liter (μg/L); the two units are equivalent.
The ferritin levels measured usually have a direct correlation with the total amount of iron stored in the body. However, ferritin levels may be artificially high in cases of anemia of chronic disease, where ferritin is elevated in its capacity as an inflammatory acute phase protein and not as a marker for iron overload.