Storage Lesion: Evolving Concepts and Controversies

Red blood cell (RBC) transfusions are a vital part of the medical management for several conditions and can be a life saving intervention. RBCs are refrigerator stored in blood banks to allow for a sufficient inventory to be readily available for patient care. These RBCs are stored in additive solutions at 1–6 °C. The extended storage of RBCs results in the RBC storage lesion, which is a series of biochemical and biomechanical changes that occur in the RBC and storage media during ex vivo preservation, reducing RBC survival and function once transfused. During storage, there are changes in RBC morphology and deformability, metabolomics, membrane consistency, and oxidation status. Furthermore, older, stored RBCs are more likely to be hemolyzed, both by intravascular and extravascular hemolysis. Several observational studies suggest that the RBC storage lesion is clinically relevant with better outcomes when fresher blood is transfused. However, recent randomized controlled trials suggest no significant differences between transfusion of fresh blood and the current standard of practice. However, these studies did not test whether transfusion of the oldest RBCs (i.e., between 35 and 42 days old) is harmful. Thus, despite these trials, controversy still remains regarding how significant the RBC storage lesion is clinically and whether RBCs transfused after prolonged storage cause harm.