Iron Binding Capacity

Iron is transported in plasma complexed to the metal-binding globulin, transferrin, which is synthesized in the liver. Total iron binding capacity is calculated from transferrin levels measured immunologically. Each molecule of transferrin has two iron-binding sites, so its iron binding capacity is 1.47 mg/g. Normally, transferrin carries an amount of iron representing about 16?60% of its capacity to bind iron, ie, % saturation of iron binding capacity is 16-60%.

 Normal Range: 250-460 µg/dL

increased in: Iron deficiency anemia, late pregnancy, infancy, hepatitis. Drugs: oral contraceptives. 

Decreased in: Hypoproteinemic states (eg, nephrotic syndrome, starvation, malnutrition, cancer), chronic inflammatory disorders, chronic disease, chronic liver disease. 

 

Additional: Increased % transferrin saturation with iron: in iron overload (iron poisoning, hemolytic anemia, sideroblastic anemia, thalassemia, hemochromatosis, pyridoxine deficiency, aplastic anemias). Decreased % transferrin saturation with iron: in iron deficiency (usually saturation <16%). Transferrin levels can also be used to assess nutritional status.