New formula to predict oxygen delivery capacity of red blood cells

Scientists have developed a method to assess the ability of red blood cells to deliver oxygen by analyzing their shape. This test could revolutionize transplantation, transfusion and blood bank management practices. This research was published open access in eBioMedicine, a journal integrated into Lancet Discovery Science.

The FlowScore formula, developed at the University of Oxford in collaboration with NHS Blood and Transplant, predicts the rate at which red blood cells release oxygen. This process is crucial for oxygenating body tissues, including organs and muscles, especially in patients receiving large transfusions.

Healthy red blood cells have a biconcave, dumbbell-like shape, which optimizes oxygen release. During storage in the refrigerator, red blood cells experience energy stress and become more spherical, which hinders oxygen release.

Factors influencing the release of oxygen from red blood cells were identified within the Department of Physiology, Anatomy and Genetics at Oxford, but the testing method was too complex for routine use in blood transfusion agencies wishing to improve monitoring stored blood. To adapt these results to the blood bank, the NHS Blood and Transplant Component Development Laboratory joined the project, providing blood samples stored according to NHS protocols and measurements from haematology analyzers.

During traditional blood testing, hematology analyzers use flow cytometry, a method that passes cells through a laser beam to study their characteristics. When light hits a cell, the scattering pattern reveals information about its size and shape. This information was found to accurately predict oxygen release from red blood cells, and the predictive formula was named FlowScore. This innovation makes measurements of oxygen transport by red blood cells simpler, faster and more accessible for laboratories globally.

Blood banks can now use FlowScore as a quality control measure during processing and storage. For example, FlowScore made it possible to quantify the beneficial effects of rejuvenation and to detect periods of blood handling outside of quality conditions. This could prove crucial for monitoring the quality of stored blood in developing countries with higher ambient temperatures. Additionally, FlowScore could be used to check blood quality for specific patient groups, if future research demonstrates a benefit to patients.

We find that FlowScore is a good indicator of oxygen handling by red blood cells and provides new and important information about oxygen transport in the blood. Outside of its applications in transfusion medicine and blood banking, FlowScore can also help identify novel genetic, environmental and lifestyle factors that influence oxygen delivery to tissues.

Pawel Swietach, Professor of Physiology, University of Oxford

Dr Peter Smethurst, from NHSBT's Component Development Laboratory, said: “FlowScore could become fundamental to the way blood is tested to ensure its quality. This is a technical advance that is expected to improve the monitoring of stored blood and generate beneficial improvements for vulnerable recipients of red blood cell transfusions. »

Dr Rebecca Cardigan, Head of the Component Development Laboratory at NHSBT, added: “FlowScore is an accessible indicator of cellular performance to complement other quality measures. It has been very exciting to lead this interdisciplinary collaboration, translating Oxford's excellent basic research to establish better assessment of stored blood and transfusion practices across the world. »