EPO and folate deficiency: According to EACTA/EACTS 2017 Guidelines on PBM in cardiac surgery [7], erythropoietin with iron supplementation should be considered to reduce post-operative transfusion in patients with non-iron deficiency anemia (e.g., EPO, vitamin D or folate deficiency) undergoing elective cardiac surgery (Class of recommendation IIb, level of evidence C).