RBC concentrates from male or female donors ages 18–90 years old were stored (1–6°C) for 39–42 days in transfer bags and tested for storage or stress-induced hemolysis as described in Materials and Methods. A. Percent AAPH-induced oxidative hemolysis (150mmol/L, 1.5h, 37°C) (n=10,476). B. Percent osmotic hemolysis (n=12,799). C. Percent spontaneous storage hemolysis (n=12,753). D. Donor plasma ferritin (ng/mL) (n=13,323). Error bars represent standard errors of the mean. Asterisks represent statistical significant difference in mean hemolysis or ferritin between first- time/reactivated donors and each of the donation frequency bin for male and female (p < 0.001). Hemolysis measures were normalized for blood center differences in blood component manufacturing procedures.