Functional iron deficiency in subjects receiving rHuEpo. (Top) Production of RBC with abnormally low Hb concentration in 3 normal subjects receiving rHuEpo to promote autologous blood donation. The percentage of RBCs with cell Hb concentration lower than 28 g/dL is plotted on the y-axis versus time (x-axis). The dose used in this trial was 200 IU/kg/d SC for 3 weeks. rHuEPO was started 1 week ahead of blood donations.58 (Bottom) Production of reticulocytes with abnormally low Hb content (CHr) in 24 normal males receiving 1,200 IU/kg of rHuEpo over 10 days. The dose was divided into either 4, 3, or 2 administrations (groups A, B, and C, respectively). Group C has higher baseline ferritin values compared with group A.60 103