Serum ERFE and hepcidin in EPO-treated patients and in β-thalassemia. (A) Serum ERFE in 4 patients with moderate anemia treated on day 0 with EPO 20 000 units subcutaneously. Blood samples were obtained every 6 hours the first day, then on mornings of days 2, 3, 5, and 7. (B) Serum hepcidin in the same samples as panel A. The patient designated by green symbols was iron deficient (serum ferritin 14, transferrin saturation 17%, undetectable serum hepcidin). (C) Serum ERFE in patients with β-thalassemia, nontransfused (Non), before transfusion (Pre), or after transfusion (Post). Box plots show median, box 25% to 75%, whiskers 10% to 90%, and outliers. Serum ERFE levels were massively increased in nontransfused and pretransfusion thalassemic patients but were closer to normal after transfusion, *P < .05, 1-way ANOVA on ranks, comparing with normal reference group of combined male and female blood donors before donation. (D) Serum hepcidin in the same samples, vs ERFE; scatterplot is fitted by an inverse third-order equation, R2 = 0.7 and P < .0001.
