Iron deficiency has important clinical significance in the American population. Many women are at risk for iron deficiency anemia and those who are blood donors are more susceptible for iron deficiency anemia due to the increased blood loss. The traditional measure of hemoglobin fails to detect the first two stages of iron deficiency. Because female blood donors are at higher risk for iron deficiency it is necessary to improve detection of the earlier stages of iron deficiency before anemia and other clinical symptoms are manifested. Female blood donors exhibit a protective mechanism and have been found to increase rates of iron absorption due to a hypothesized increase in their setpoint for iron storage. The increased demand for iron as a result of blood donation is due to increased activity of erythropoiesis. Iron supplementation may be an important factor in preventing iron deficiency anemia in repeat female blood donors.