This is a plain English summary of an original research article
Transfusing more recently-collected red blood cells does not improve the chance of survival for critically-ill people who need blood transfusions, compared with blood that has been stored for longer.
This large international study included almost 5,000 critically ill people in intensive care units. Participants were transfused with either the freshest compatible blood available (mean storage 11.8 days) or the oldest compatible stored blood within its use-by date (mean storage time 22.4 days).
There was no difference in deaths between the two groups. Almost a quarter of people died in each group by 90 days. There were also no differences in other outcomes such as length of stay in intensive care.
This provides strong evidence to support the practice of transfusing the oldest compatible red blood cells to minimise waste of precious and costly blood stocks when they become out-of-date. In the UK, this is up to 35 days from donation.
Why was this study needed?
Transfusions of red blood cells into critically-ill patients are common. Most hospitals around the world use the oldest stored blood within the use-by date, to make the most efficient use of stored blood products and minimise waste. However, concerns have been raised about whether blood that has been stored for longer could have less benefit and evidence from older studies has been inconsistent.
A recent randomised controlled trial (ABLE) found no association between age of red blood cells and chances of survival after 90 days. ABLE was smaller (2,430 adults) than the current study and compared red blood stored for seven days or less with older blood. Notably, ABLE also found no difference in cost between the use of older and newer blood.
This study aimed to compare usual practice with freshest-available blood.
What did this study do?
Researchers for the TRANSFUSE study carried out a double-blinded randomised controlled trial. They randomised 4,994 critically-ill participants from 59 intensive care centres in five countries (Australia, New Zealand, Ireland, Finland and Saudi Arabia) who had been prescribed red blood transfusions. Participants were assigned to either freshest available compatible red blood cells or oldest available compatible red blood cells.
Researchers followed up participants for 180 days. The main outcome was death after 90 days, although they also looked at death after 28 days, blood infection, and other secondary outcomes.
The study was robust and strengthens the evidence on this topic.
What did it find?
- Participants were equally likely to have died by 90 days after randomisation, whether they had fresher blood (610 of 2,457 patients, 24.8%) or longer-stored blood (594 of 2,462 patients, 24.1%). The absolute risk difference of 0.7% was not statistically significant (95% confidence interval [CI] -1.7 to 3.1).
- Similar results were shown after 180 days with 687 (28.5%) deaths following fresher blood and 678 (28.1%) after longer-stored blood, (absolute risk difference 0.4%, 95% CI ‑2.1 to 3.0).
- There was no difference between the two groups for death after 28 days, length of stay in intensive care, bloodstream infections or organ support including use of mechanical ventilation or renal replacement therapy.
What does current guidance say on this issue?
Guidelines from the Joint United Kingdom (UK) Blood Transfusion and Tissue Transplantation Services Professional Advisory Committee govern the preparation and storage of blood products in the UK.
A minimum of 75% of red cells is expected to survive 24 hours after transfusion and the guidelines state that red blood cells can be used for up to 35 days. The guidelines do not state whether fresher or older blood products should be used first, however.
What are the implications?
The study findings suggest that hospital intensive care and emergency departments can use the oldest compatible stored blood, within storage guidelines, when supplying red blood cells for transfusion into critically ill adults.
This practice should allow them to make the most efficient use of donated blood, with as little as possible going to waste because they pass the use-by-date.
Citation and Funding
Cooper DJ, McQuilten ZK, Nichol A, et al.; TRANSFUSE Investigators and the Australian and New Zealand Intensive Care Society Clinical Trials Group. Age of red cells for transfusion and outcomes in critically ill adults. N Engl J Med. 2017;377:1858-67.
The study was funded by grants from the Australian National Health and Medical Research Council, the Health Research Council of New Zealand, the Irish Health Research Board and the Australian Red Cross Blood Service.
Joint United Kingdom (UK) Blood Transfusion and Tissue Transplantation Services Professional Advisory Committee. Transfusion Handbook Chapter 3.3, Blood Products.
Walsh TS, Stanworth S, Boyd J, et al. The Age of BLood Evaluation (ABLE) randomised controlled trial: description of the UK-funded arm of the international trial, the UK cost-utility analysis and secondary analyses exploring factors associated with health-related quality of life and health-care costs during the 12-month follow-up. Health Technol Assess. 2017;21(62).
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