![cover image](https://wikiwandv2-19431.kxcdn.com/_next/image?url=https://upload.wikimedia.org/wikipedia/commons/thumb/3/32/ABO_blood_type.svg/640px-ABO_blood_type.svg.png&w=640&q=50)
ABO blood group system
Classification of blood types / From Wikipedia, the free encyclopedia
The ABO blood group system is used to denote the presence of one, both, or neither of the A and B antigens on erythrocytes (red blood cells).[1] For human blood transfusions, it is the most important of the 44 different blood type (or group) classification systems currently recognized by the International Society of Blood Transfusions (ISBT) as of December 2022.[2][3] A mismatch in this serotype (or in various others) can cause a potentially fatal adverse reaction after a transfusion, or an unwanted immune response to an organ transplant.[4] Such mismatches are rare in modern medicine. The associated anti-A and anti-B antibodies are usually IgM antibodies, produced in the first years of life by sensitization to environmental substances such as food, bacteria, and viruses.
![Thumb image](http://upload.wikimedia.org/wikipedia/commons/thumb/3/32/ABO_blood_type.svg/640px-ABO_blood_type.svg.png)
The ABO blood types were discovered by Karl Landsteiner in 1901; he received the Nobel Prize in Physiology or Medicine in 1930 for this discovery.[5] ABO blood types are also present in other primates such as apes, monkeys and Old World monkeys.[6]