GSTM1 and anemia (phenotype): We determined the percentage of blood donors with anemia as defined by the WHO (Venous Hb < 120 g/l for women and < 130 g/L for men) and low hemoglobin as defined by low hemoglobin deferral thresholds (Venous Hb < 125 g/l for women and < 135 g/L for men).