Serum ferritin in the regulation of iron therapy in blood donors.

12 regular blood donors were selected on the basis of subnormal serum ferritin levels as a criterion for iron deficiency. It was found that all had high transferrin levels but only 5 had subnormal serum iron or transferrin saturation. The donors were given oral iron therapy in a dose of 2,800 mg between each phlebotomy, and the donation interval was standardized to 8 weeks. Test samples were collected every 4th week. After an initial rise in ferritin during the first 2 months, 6 of the donors again had subnormal serum ferritin levels, and the iron dose was therefore doubled after 32 weeks. Following this, all subjects taking the higher dose had normal ferritin values and stainable marrow iron was found at the end of the study, after 92 weeks. 3 subjects did not take the higher dose, had no raised serum ferritin level or stainable hemosiderin. It is concluded that serum ferritin estimation can be used to monitor the therapy in blood donors so that a satisfactory amount of iron is stored.