A new genetic blood test that allows a much closer match between donors and recipients is being developed by an international team of researchers.
Existing blood testing checks for two main differences
The Bloodchip can give much more detailed results than existing tests.
It looks for DNA "signatures", rather than broader blood types, as the existing test does.
A spokeswoman for the National Blood Service, which is helping develop the test, said it could be "a lifesaver" for those needing regular transfusions.
It is hoped the test could be of particular benefit to people with blood conditions such as sickle cell anaemia, haemophilia, thalassaemias and leukaemia.
People with these conditions need regular blood transfusions, and can develop life-threatening side effects if they are not receiving a perfect match, the developers of Biochip warn.
The test is currently undergoing "proof of principle" testing on 3,000 healthy blood samples, which show it is accurate compared to existing tests, in order to gain European health and safety approval.
People can be blood group A, B, AB or O. They may also be either carry the rhesus antigen and therefore be rhesus positive or negative.
This is the information provided by the current serological test which checks for proteins which will identify which group and rhesus type someone is.
The Bloodchip test looks at up to nine other potential variations in people's blood, such as the Duffy system - blood can be Duffy A or Duffy B.
The test could detect up to 116 blood type DNA "signatures" once variations in each system are taken into account.
It uses a glass microscopic slide which tests the DNA extracted from blood samples.
Chemicals are added to the DNA on the slide which causes reactions that show up as fluorescent colours.
The slide is then placed in a scanner which looks for the blood types.
Professor Neil Avent, director of University of West England's Centre for Research in Biomedicine who has been involved in the research, said: "Blood transfusions are inherently safe.
"But with the compatibility between the donor and the recipient being tested using serological techniques, there is a significant section of the population that suffer serious illness and side effects after receiving multiple transfusions of blood that is not a perfect match.
"These patients over time develop antibodies that reject imperfectly matched blood transfusions, a process known as alloimmunisation, which can lead to serious illness and life-threatening side effects.
"Bloodchip has been developed with these communities in mind."
'A perfect match'
Professor Marion Scott, national director of research at the UK National Blood Service, said: "The Bloodchip test will literally be a lifesaver for those who suffer from illnesses that require multiple blood transfusions such sickle cell disease and thalassaemias.
"Sickle cell disease and thalassaemias are particularly prevalent in those from African, Caribbean, Eastern Mediterranean, Middle East and Asian backgrounds and both can be life-threatening.
"The Bloodchip test will be of enormous benefit in ensuring those with these disorders receive perfectly matched blood to enable them to better manage their conditions."
Researchers in the UK, Germany, Sweden, Spain, the Czech Republic and the Netherlands have formed a consortium called Bloodgen to develop the test, which will be manufactured by Progenika Biopharma in Spain.