Hemoglobin, serum ferritin, and serum soluble transferrin receptor-1 concentrations in male patients with dominant EPP. (A). Hemoglobin concentrations in 66 male patients with dEPP aged 16 years or older (■) and in a sample of 5206 men aged 16 years or older from the English population17 (□). (B) Serum ferritin concentrations in 66 male patients with dEPP aged 16 years or older (■) and in 612 male first-time blood donors from south Wales aged 17 to 62 years16 (□). (C) Serum soluble transferrin receptor-1 concentrations in 61 male patients with dEPP aged 16 years or older (18.6 ± 5.1 nM) (■) and in 225 hematologically healthy male and female subjects from the United States aged 17 to 97 years18 (□) assayed using the same method.