Rare Blood

One in 10,000 people has blood that is not shared by 99.99% of the rest of citizens. It is called "rare blood." This means that between 0.01 and 0.1 per cent of the population has "special" blood, and when they receive a transfusion from any donor, their body may not tolerate it.

The recipient with 'rare blood' will produce antibodies against the blood group they receive because it detects it as a foreign agent and activates defense mechanisms. Currently, there are more than 300 blood groups described, but the most common are ABO and Rh.

What differentiates people with rare blood is precisely not having these majority blood groups or 'public' blood groups that 99.99% of mortals have. The strange phenomenon here is "not having," and that is why their system is altered when receiving blood with blood groups unknown to their body.

So, what happens if a person with "rare blood" has an accident and urgently needs blood? This person will necessarily have to receive blood from this 0.01% that is identical to theirs. That is why the World Health Organization (WHO) seeks to have these donors located worldwide. In our country, aware that unity is strength, a network of specialized centers in rare blood groups was created in 2005, which is part of a broader panel managed by the WHO.

The Blood and Tissue Bank is part of the network of specialized centers in rare blood phenotypes in the country, along with three other organizations: transfusion centers in the Community of Madrid, the Valencian Community, and Galicia. However, in Catalonia, we have more than 350 special phenotypes, almost half of what exists in the country.

Internationally, the coordination of this network is carried out by the Bristol Transfusion Institute in the United Kingdom, which has all records of frozen rare units and existing donors. There are more than 5,000 records (between donors and frozen blood) belonging to 60 centers from 26 different countries, and demands at an international level are coordinated from Bristol.

Dr. Núria Nogués, head of the immunohematology laboratory at BST, is an expert in special phenotypes. At the Blood Bank, we have located around half a thousand donors with rare blood groups, whom we call when a patient needs them.