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INTERVAL study shows safety of more frequent blood donations

last modified Oct 04, 2017 03:42 PM

Whilst blood donation has been practiced for over a century, the INTERVAL study is the first randomised trial on blood donation frequency. Consequently, blood donation practices have varied widely across the globe.

In the UK, current practice allows men to donate at 12-week intervals and women at 16-week intervals. However, INTERVAL has shown that many blood donors could donate more frequently than current UK practice dictates as the researchers compared UK practice with shorter inter-donation intervals used in other countries.

The study, recently published in the Lancet, was conducted by Cambridge and Oxford Universities and NHS Blood and Transplant (NHSBT), and was led by a group of Cambridge researchers, including Dr Emanuele Di Angelantonio, Prof Simon Thompson, Prof Willem Ouwehand, and Prof John Danesh.

The study involved 45,000 blood donors - men were randomly assigned into groups giving blood at 12, 10, and 8-week intervals, and women to groups giving blood at 16, 14, and 12-week intervals. Donors were asked to report any symptoms potentially related to the increased blood donation.

The results showed that giving blood more frequently boosted blood supplies for NHSBT and had minimal impact on most donors’ quality of life, mental function or physical activity. Those who weighed above average and those with higher initial stores of iron were able to give more blood.

However, some people who gave blood more frequently did report minor symptoms including tiredness and restless legs, and the research suggests this may have been due to giving blood. People giving blood most frequently also had lower haemoglobin levels after two years and were more likely to have haemoglobin levels below the minimum threshold to donate blood.

These results give blood services the short-term option of more frequent collection from donors if supply falls or demand rises and will help in framing the safety guidelines in countries where blood donation is more frequent than in the UK.

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