Scientists from the French Blood Establishment (EFS) has successfully identified the ultra-rare 48 th blood type group, known as “Gwada negative,” which came from a blood sample originally drawn some 15 years ago. blood type group, known as “Gwada negative,” which came from a blood sample originally drawn some 15 years ago. However, the International Society of Blood Transfusion (ISBT) only recognizes 47 distinct blood type groups, with the latest being added just last year after a 50-year-long mystery. Although there are potentially millions of blood types, transfusions made with blood that matches your type according to the well-established ABO-Rh type system have a 99.8 percent chance of success. For example, the 44th member of this group, known simply as “Er,” was discovered in 2022, meaning that scientists are currently discovering more than one new blood group a year.