EPO and stage 5 chronic kidney disease: In patients affected by chronic kidney disease (CKD), the life span of RBCs is further shortened [13]: the main contributor is the relative deficit of erythropoietin (EPO) [14,15], iron deficiency plays also a significant role, but it was recently proven that the erythrocytes of patients with end-stage renal disease (ESRD) show an increased percentage of PS externalization and subsequent eryptosis, if compared to healthy individuals [16].