Rare blood types
Some people rely on donations of rare blood types to stay well.
When someone needs regular transfusions, they need blood that's closely matched to their own. If you have a rare blood type, your blood could be vital for a patient who also shares that type.
What's the rarest blood type?
AB negative is the rarest of the 8 main blood types. Demand is for AB negative is relatively low and thanks to our current donors we usually have enough to meet patient need.
Rare blood types in demand
- The Ro subtype is vital for treating sickle cell disorder but only 3% of regular donors have it.
- B negative is rare in the general population and is often used by hospitals when Ro isn't available.
- O negative can be given to anyone in an emergency and always in high demand.
How ethnicity affects rare blood types
Your blood type is inherited from your parents in the same way as eye or hair colour.
This means you are more likely to share the same blood type or subtype as someone from the same ethnic background.
For example, Ro is a rare subtype but it’s 10 times more common in people of Black heritage.
Growing demand for the Ro subtype is one of the reasons why we need more donors of Black heritage.
What makes blood rare?
Although the ABO and Rh groups are the most important for blood transfusions, there are 36 other known blood groups.
Each blood group has a combination of sugars and proteins called antigens that are found on the outside of red blood cells.
There are more than 600 antigens so there’s potential for a lot of variation between different people.
If your blood has rare antigens or lacks common antigens you could have a rare subtype.
Learn more about the Rh system
Why are rare blood subtypes important?
Most blood transfusions are based on the ABO and Rh groups.
But if someone needs ongoing transfusions, blood works best when it closely matches their own.
If you have a rare subtype, your blood could be vital for a patient who also shares that subtype.
If you give blood, you'll find out if you have a rare subtype after your first donation.
How we find and use rare blood
Every donation is tested in our labs. If your blood is rare, we may:
- call you when it’s urgently needed
- share it with hospitals across the UK
- in some cases, share it internationally for patients abroad
How rare blood types help
Rare blood types can be the difference between life and death for patients:
- living with sickle cell disorder or thalassaemia
- undergoing complex surgery or cancer treatment
- needing emergency transfusion after an accident
Could your blood be rare?
You won't find out your blood type or subtype until you give blood for the first time.
Every unit is tested in our labs. If your blood is rare, we'll let you know.