Scientists from Bristol University in the UK say they have found a way to mass produce blood that would be suitable for patients who need it in hospitals. For a number of years, they have been able to produce red blood cells in a laboratory. However, the process to do that was very slow and they could not produce a lot of blood. The new technique means scientists can make an "unlimited supply" of blood. Researcher Dr Jan Frayne said: "Previous approaches to producing red blood cells have relied on various sources of stem cells which can only presently produce very limited quantities." She added: "We have demonstrated a feasible way to sustainably manufacture red cells for clinical use."

Professor David Anstee, another of the researchers, told the BBC that his team has found a way to mass produce blood, but they now need the technology to actually do this on a large scale. He said: "There is a bioengineering challenge. To produce that much [blood] is quite a challenge….The next phase of our work is to look at methods of [producing more]." He told reporters that to begin with, they would produce only rare types of blood, as these can be difficult to find with traditional blood donation sources. He said: "The first therapeutic use of a cultured red cell product is likely to be for patients with rare blood groups, because suitable conventional red blood cell donations can be difficult to source."