A recent study conducted by the Cleveland Clinic indicated that heart surgery patients who receive transfusions of blood more than two weeks old were more likely to die or suffer serious complications than patients who receive fresher blood. According to an AP report:

The study found that the one-year survival rate was 89 percent for those who got older blood, but nearly 93 percent for patients who got fresher blood.

Complication rates were higher in the older blood group, with higher proportions of those patients suffering kidney failure, blood infections or multiple organ failure, or needing ventilator care more than 72 hours after surgery.

The average age of the “old” blood was 20 days. The average age of the fresher blood was 11 days.

Currently, the Food and Drug Administration permits the use of blood as old as six weeks. The rule exists to help blood banks survive shortages and to preserve supplies of rare blood types.

The authors of the Cleveland Clinic study say that their results do not warrant an immediate change in FDA policy. At least not yet. The study’s lead author said a more rigorous test is currently under way, and that its results will determine whether the FDA ought to be persuaded to change its policy.

To learn more about what happens to blood when it leaves your body, take our Blood Journey on RED GOLD: THE EPIC STORY OF BLOOD.