Older Blood Boosts Chances of Infection in Transfusion Patients

ByABC News
October 28, 2008, 3:02 PM

Oct. 29 -- TUESDAY, Oct. 28 (HealthDay News) -- Hospital patients who receive a transfusion of stored blood that is 29 days or older face double the risk for developing one or more serious infections compared to those who get "fresher" blood, new research indicates.

The study authors pointed out that current U.S. regulations set the upper limit for blood storage at 42 days, at which point the blood must be thrown away. Yet, the latest finding suggests that infection risk might actually begin nearly two weeks before that accepted cut-off date.

"This issue is something that has been on the radar for some time, so the idea that aging blood can pose problems is not completely new," said study author Dr. Raquel Nahra, who conducted her research while at Cooper University Hospital in Camden, N.J. "But the bottom line here is that what we found is that patients who received blood transfusions with blood 29 days or older appeared to have a greater risk for infection."

Nahra is currently working at Stark Medical Center in Fort Smith, Ark. She and her colleagues were scheduled to present their findings Tuesday at the American College of Chest Physicians annual meeting, in Philadelphia.

The observations follow a 2006 finding from Duke University Medical Center researchers that seriously ill heart patients who received a transfusion of older blood -- between 31 to 42 days old -- faced a higher risk of death than similar patients who got "fresher" blood (stored for up to 19 days).

The new research team noted that the existing threshold was established to deal with the fact that while in storage red blood cells release cytokines, which are known to dampen a transfusion patient's immune system -- rendering the patient more susceptible to infection.

Cytokine release tends to begin around two weeks into blood storage, mounting to maximum levels even after the 42-day line in the sand.

To get a handle on possible links between blood age and infection risk among transfusion patients, Nahra and her colleagues analyzed records concerning 422 transfusion patients -- average age 66 -- who had been admitted to a single hospital intensive care unit between 2003 and 2006.