Old Blood Is Bad Blood: Study

Donated blood may have a much shorter shelf life than previously thought, finds a study published today in the New England Journal of Medicine. Transfusions using blood at least two weeks old increased heart-surgery patients' post-operative death risk by 30%, researchers discovered, though the current expiration date for blood is 6 weeks after donation, reports USA Today.

The Cleveland Clinic team focused on heart patients around 70, prompting calls for additional research into other uses of donated blood. The American Red Cross calls the study "provocative," but cautions that "it's not really appropriate to conclude that old blood is bad." The next step will be a rigorous clinical trial, says the study's author. (More blood transfusions stories.)