The administration of EPO or ESAs is a common therapeutic approach applied to stimulate and support erythropoiesis, particularly in patients with anemia associated with end-stage renal disease (21), patients with nonmyeloid cancer on chemotherapy, patients with HIV treated with zidovudine (58), or patients undergoing an elective, noncardiac nonvascular surgery to reduce the need for allogeneic blood transfusions (55). Here, EPO is linked to anemia (phenotype).