29 September 2017

Is it OK to use older blood for transfusions?

Being able to safely use older blood for transfusions could help tremendously when blood banks face a shortage.

In April 2017 it was reported that the South African National Blood Service (SANBS) was facing a serious shortage of type O blood, with just over a day and a half's supply in its banks across the country.

The current blood stock at SANBS is enough for 2.2 days, the major shortage still being type O blood.

It was once believed that fresh red blood cells were best suited for transfusions. But a new Australian study has added to the evidence that older blood is just as good, if not better.

Using older red blood cells in transfusions to critically ill patients doesn't appear to increase their risk of dying, Australian researchers report.

A little older, a little better

"Red blood cells for transfusion for critically ill patients are like a good red wine – a little older, a little better," said researcher Dr Jamie Cooper. He is professor and director of the Australian and New Zealand Intensive Care Research Centre at Monash University in Melbourne.

Study co-author Alistair Nichol added that a lot of inadequate research had suggested that fresher blood would be better to use in critically ill patients. Nichol is an associate professor of epidemiology and preventive medicine in the School of Public Health and Preventive Medicine at Monash University.

The report was published online in the New England Journal of Medicine to coincide with the presentation of the study findings at the European Society of Intensive Care Medicine meeting in Vienna, Austria.

The current practice is safe

The current practice is to use the oldest available blood, Nichol said. Red blood cells can be stored for up to 42 days, the researchers noted.

"But due to concerns about the use of older blood, some blood banks had been reducing the age of the blood they transfuse," Nichol said. Reducing the age of blood for transfusions, however, may result in more blood shortages, he pointed out.

"The current practice is safe and doctors no longer need to try and get the freshest available blood for their patients," Nichol said. He added that using newer blood to give transfusions to critically ill patients may be harmful.

Small difference in death figures

From November 2012 through December 2016, the researchers randomly assigned nearly 5 000 critically ill patients to receive blood transfusions with either newer or older blood. The patients were from 59 medical centres in five countries – Australia, Finland, Ireland, New Zealand and Saudi Arabia.

Newer blood had been stored for an average of 11 days, while older blood was about 22 days old.

Ninety days after the transfusion, 24.8% of patients who received newer blood died, while 24.1% of those who had received older blood died, the findings showed.

After six months, the difference in deaths between those who received newer or older blood remained less than 1%.

According to Dr Edward Murphy, a professor of laboratory medicine at the University of California, San Francisco, these findings are consistent with other recent studies. "To my mind, the issue is settled that there is not a significant difference in outcomes related to how you store the blood cells," Murphy said. "It's reassuring that there is no difference."

Image credit: iStock 


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