Blood of rare or uncommon phenotypes

Some people have a very rare blood group, found in only 1 out of every 1000 donors, or even 1 out of every 10,000 donors in the case of the rarest or most exceptional phenotypes. These are known as rare blood groups.

Although the most well-known are the ABO and Rh systems, currently more than 360 blood group antigens have been described. Rare phenotypes are defined by the absence of one or more blood group antigens that are present in 99.9% of the population. That is, what defines "a rare blood group" is not having a special antigen, but rather not having one that is common for most people.

When a person with a rare phenotype requires a transfusion or goes through a pregnancy, they can develop antibodies against antigens they do not have, making it very complicated to find compatible blood. In these cases, finding a donor with the same rare phenotype becomes a real challenge.

To address this need, the Blood Bank is part of the international network of rare blood registries, coordinated by the International Blood Group Reference Laboratory (IBGRL) in Bristol, United Kingdom. This network aims to facilitate the quick location and exchange of blood with especially rare phenotypes between countries.

In Catalonia, we currently have identified around 250 donors with rare phenotypes. These donors are specifically contacted when there is a patient who needs their blood.

Contributing to blood donation is essential to ensure that, even in the most exceptional cases, we can provide the necessary response to those in need.