Researchers in the UK have conducted a world-first clinical trial using blood grown in a lab.
To see how it works inside the body, tiny amounts - equivalent to a couple of spoonfuls - are being tested.
People are always needed to donate blood regularly to ensure the bulk of blood transfusions are provided. However, the ultimate goal is to manufacture vital, but ultra-rare blood groups. People with conditions such as sickle cell anaemia who require regular blood transfusions need these. The body begins to reject blood if it is not a precise match, and the treatment fails.
There might only be ten people in the country able to donate to some groups, according to Prof Ashley Toye from the University of Bristol.
There are currently only three units of the "Bombay" blood group - identified in India - available in the UK.
This research paves the way for creating red blood cells that will be used to safely transfuse people with disorders such as sickle cell.
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