Blood bags and transfusions

The qualification of red blood cells is a central issue in blood donation and the storage of blood bags for blood transfusions. Transfusion efficacy, assessed as the percentage of red blood cells remaining in circulation 24 hours after transfusion, is inversely correlated with the length of time red blood cells are stored. The Food & Drug Administration (FDA) standard is less than 1% hemolysis during storage, and 75% of red blood cells remaining in circulation at 24h for a 42-day bag, the maximum shelf life. Today, ~15% of blood transfusions fail to meet these criteria. The most fragile red blood cells are the least deformable, and it is recognized that in vivo they become rigid over time, leading to their elimination from the blood microcirculation. The loss of deformability of red blood cells and the release of heme could be a cause of reduced transfusion quality of blood bags. Complementary causes involving the quality of blood from particular donors are also put forward.

Finding an in vitro marker predictive of the ‘transfusion performance’ of red blood cells during storage is a major challenge for 1) routine quality testing prior to blood delivery, 2) measuring transfusion potential in terms of red cell deformability as soon as blood is donated, and optimizing its orientation and use, and 3) research studies into the causes (genetic, environmental, etc.) leading to premature red cell degradation.