The rarest blood group in the world is the so-called Gwada negative, discovered only in a woman originally from Guadeloupe in 2025.
The record for the rarest blood group in the world goes to the so-called Gwada negative, discovered in 2025 by the Établissement Français du Sang (Efs) in a single woman originally from Guadeloupe. The sample had already been collected in 2011, but only in 2019, thanks to genetic sequencing, did researchers clarify that it was a new system, the 48th officially recognized by the International Society of Blood Transfusion (ISBT).
Good news for transfusions. This discovery showed how modern genetics can reveal blood variants invisible to traditional tests, and represents an important step because each new group identified improves the safety of transfusions.
Antigens. The rarest group detected in multiple subjects is Rh-null, also known as “golden blood”. Discovered in 1961, it is devoid of all Rh antigens and can be donated to anyone with a negative Rh group without risk of rejection.
Unfortunately, however, its extreme rarity (less than 50 known cases in the world) also makes it impossible to find.
