Serum ferritin levels in male blood donors: relation to number of phlebotomies and iron supplementation.

Serum ferritin estimation has been shown to be a reliable test to reveal iron deficiency. Such estimations have been made in groups of male blood donors with a varying number of previous phlebotomies and a mean interval between donations of 9.9 +/- 1.7 SD weeks. It was found that the mean ferritin level was significantly (p less than 0.001) lower in the blood donors than in nondonors. After 6-8 phlebotomies it was about 40% lower. Subnormal ferritin values were found in 10% of the donors, almost exclusively among those who had taken less than 1,000 mg of iron supplementation since the last donation. It is concluded that with a donation interval of about 10 weeks, there is a considerable risk for iron deficiency after about 6 donations. This risk is far less if more than 1,000 mg of iron supplementation is taken between phlebotomies. A role for serum ferritin estimation in monitoring donation intervals and/or iron therapy is suggested.