Transferrin is a direct measure of the iron binding capacity. Transferrin is thus useful in assessing iron balance. Iron deficiency and overload are often evaluated with complementary laboratory tests. Normally, iron is absorbed from food and transported throughout the body by transferrin, which is produced by the liver. About 70% of the iron is transported to the bone marrow and incorporated into the production of hemoglobin within red blood cells. The remainder is stored in the tissues as ferratin or hemosideran The amount of transferrin in the blood depends upon liver function and a person’s nutritional status. Under normal conditions, its binding sites are typically one-third saturated with iron. This means that two-thirds of its capacity is held in reserve.
A 12-hour fast required.