Time course of Hb level, sEpo, and sTfR in a patient with PRCA responding to treatment. The patient was given rHuEpo at an initial dose of 150 U/kg per day SC, 5 days a week; dosage was reduced to three weekly administrations when Hb level achieved 12 g/dL and treatment was discontinued after 8 weeks. Serum Epo started to decrease as erythroid marrow activity reappeared, before any change in Hb level.