Ferritin

Definition

Ferritin is the cellular storage protein for iron, with 1 ng of ferritin per mL indicating 10 mg of total iron stores. It is a huge (440 kDa), 24-subunit protein consisting of light and heavy chains, which can store up to 4,500 atoms of iron. Ferritin is an acute-phase reactant, and, along with transferrin and its receptor, coordinates cellular defense against oxidative stress and inflammation. Ferritin measured clinically in plasma is usually apoferritin, a non " “iron-containing molecule.
Normal range:
- Male: 23 " “336 ng/mL (in patients with normal iron stores, it should be >30 ng/mL)
- Females: 11 " “306 ng/mL

Predict and monitor iron deficiency
Determine response to iron therapy or compliance with treatment
Differentiate iron deficiency from chronic disease as cause of anemia
Monitor iron status in patients with chronic renal disease with or without dialysis
Detect iron overload states and monitor rate of iron accumulation and response to iron depletion therapy
Population studies of iron levels and response to iron supplement

Acute and chronic liver disease.
Alcoholism (declines during abstinence).
Malignancies (e.g., leukemia, Hodgkin disease).
Infection and inflammation (e.g., arthritis).
Hyperthyroidism, Gaucher disease, acute myocardial infarction.
Iron overload (e.g., hemosiderosis, idiopathic hemochromatosis).
Anemias other than iron deficiency (e.g., megaloblastic, hemolytic, sideroblastic, thalassemia major and minor, spherocytosis, porphyria cutanea tarda).
Renal cell carcinoma due to hemorrhage within tumor.
End-stage renal disease; values ≥1,000 ˇ ¼g/L are not uncommon. Values <200 ˇ ¼g/L are specific for iron deficiency in these patients.

In hepatic, malignant, and inflammatory conditions, ferritin levels can be normal. In such cases, bone marrow stain of iron may be used to exclude iron deficiency.
Transferrin saturation is more sensitive to detect early iron overload in hemochromatosis; serum ferritin is used to confirm diagnosis and as an indication to proceed with liver biopsy. Ratio of serum ferritin (in ng/mL) to ALT (in IU/L) >10 in iron-overloaded thalassemic patients but averages ≤2 in viral hepatitis; ratio decreases with successful iron chelation therapy.
Increases with age, is higher in men than in women, in women who use oral contraceptives, and in persons who eat red meat compared to vegetarians.