THE use of freshly donated blood in transfusions offers no major benefits to patients over the current practice of using older blood, a study suggests.

Blood given to patients that 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, according to research led by Edinburgh University and the University of Ottawa in Canada.

It is the first study to show conclusively that there are no major benefits to patients from using fresher blood for transfusions.

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 has been concern among experts that older blood may carry risks for patients compared with fresher supplies.

The Age of Blood Evaluation (ABLE) study looked at 2,500 anaemic patients in intensive care units in Canada and Europe.

Half of 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 that are less than three weeks old.

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 of Edinburgh's Critical Care Research Group, who led the UK arm of the trial, said: "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."