Scots university finds ‘old blood as good as new’

Few patients receive blood that is less than three weeks old. Picture: Neil Hanna

The research by scientists at the University of Edinburgh is the first study to show conclusively there are no major benefits to patients from using fresher blood for transfusions.

The findings answer a long-standing question in medicine and provide reassurance to blood banks worldwide that can encounter shortages of donations.

Researchers found that blood given to patients which has been stored for around 21 days, which is the current standard, is as effective and safe as blood held for less than eight days before use.

Blood can be stored for up to 35 days under current UK safety regulations and up to 45 days in many other countries.

However, there was concern among experts that older blood may carry risks for patients compared with fresher supplies.

The trial found three-week-old blood is just as effective for treating anaemic patients in intensive care units, without increased incidence of major harmful side effects.

The Age of Blood Evaluation (Able) study looked at 2,500 anaemic patients in intensive care units in Canada and Europe. Researchers investigated whether the storage time of blood affects its safety and effectiveness in transfusions.

Half of the participants were given blood stored for less than eight days, while the other group was transfused with cells stored for three weeks, which is current practice in the NHS and other countries.

At present, few patients receive blood units less than three weeks old, thus enabling blood transfusion services to minimise waste.

The team found patients given fresh blood did not have an increased chance of survival compared with those given older blood, up to three months after treatment. The rate of common intensive care complications was also similar for both groups.

Professor Tim Walsh, of the university’s critical care research group, said: “We know that changes occur to blood when it is stored that might make it less effective or even harmful for patients. But using only fresh blood would have enormous implications for blood banks.

“This is the first time we’ve been able to conclusively show that the outcomes with fresher blood are no different than with the blood currently supplied by blood banks. It will be a great relief for doctors and blood transfusion services worldwide.”

Findings from the international Able study led by the University of Edinburgh and the University of Ottawa in Canada are published in the New England Journal of Medicine. The trial was funded in the UK by the Health Technology Assessment Programme of the National Institute of Health Research.