This number represents the amount of iron-binding sites that are occupied. Iron saturation is a better index of iron stores than serum iron alone. Iron saturation is calculated as
% Saturation = Serum iron/TIBC ƒ — 100
Normal range: 20 " “50%.
Use
Differential diagnosis of anemias
Screening for hereditary hemochromatosis
Interpretation
Increased In
Hemochromatosis
Hemosiderosis
Thalassemia
Birth control pills ( ≤75%)
Ingestion of iron ( ≤100%)
Iron dextran administration causes increase for several weeks (may be >100%)
Vitamin B6 deficiency
Aplastic anemias
Decreased In
Iron deficiency anemia (usually <10% in established deficiency)
Anemias of infection and chronic diseases (e.g., uremia, RA, some neoplasms)