The controversy over the age of blood: what do the clinical trials really teach us?

Red blood cell transfusions have been used in clinical practice for decades and represent the most common therapeutic procedure performed in hospitalised patients. Depending on the storage solution and national regulatory requirements, red blood cells can be stored in the refrigerator up to 42 days before transfusion. We reviewed five of the most recent randomised clinical trials that examined clinical outcomes in specific patient populations. Although these studies provide some comfort regarding our current standard of care, they do not address whether the oldest blood is associated with harm in certain patient populations.