Blood Donation and Iron Deficiency

In the United States about 40,000 people per day donate blood. Donors are from all racial/ethnic backgrounds and range in age from 16 to over 80 years old. They are allowed to repeatedly donate blood every 56 days, as long as they maintain their hemoglobin above 12.5 g/dL for females or 13.0 g/dL for males. Although each donation removes 200-250 mg of iron from the donor, testing for iron deficiency is not performed. Thus, blood donation can be viewed as a large clinical study to examine the physiological effects of repeated phlebotomy of approximately 10% of an individual's blood volume. In addition, blood donors are altruistic by nature and typically are very willing to participate in research studies. We have utilized this rich clinical population to perform studies on iron metabolism and red blood cell biology in an otherwise healthy population. These include a study of over 750,000 donors to define the demographics of anemia. A study detailing the body's response to blood donation, finding that recovery of iron stores takes over 90 days, if the donor takes daily iron pills following donation, and much longer if they do not. Despite this long time for recovery of iron stores, some donors are capable of repeatedly donating blood every 56 days for several years without experiencing a low hemoglobin deferral. Study of these "superdonors" has identified potential associated genetic variants and behaviors that allow frequent donation without development of anemia. Teenagers are allowed to donate blood in the United States at the same 56 day donation frequency and hemoglobin cut-off values as adults even though they have increased iron requirements for continued growth and neurocognitive development. A study detailing the impact of blood donation on teenager hemoglobin and iron stores has found that they are more susceptible to iron deficiency than adults, and, therefore, should have extra protections to prevent donation-induced iron deficiency.