a, Total Hb concentrations in whole blood. Red dots, transfusion time points; black vertical arrow, the last time the patient was transfused; red arrows, phlebotomies (200 ml each) to remove excess iron. b, HPLC blood globin chain profiles. Note that βA only derives from blood transfusions. c, Contribution of each Hb species, quantified by HPLC, to total blood Hb concentrations (in g dl–1). Actual numbers for each Hb species are indicated above the chart.