ABO blood group system During the 1930s, connecting blood groups to personality types became popular in Japan and other areas of the world. Studies of this association have yet to confirm its existence definitively. Other popular but unsupported ideas include the use of a blood type diet, claims that group A causes severe hangovers, group O is associated with perfect teeth, and those with blood group A2 have the highest IQs. Scientific evidence in support of these concepts is nonexistent. ABO blood group system The ABO blood group system is used to denote the presence of one, both, or neither of the A and
ABO blood group system ABO blood group system The ABO blood group system is used to denote the presence of one, both, or neither of the A and B antigens on erythrocytes. In human blood transfusions it is the most important of the 36 different blood type (or group) classification systems currently recognized. A very rare (in modern medicine) mismatch in this, or any other serotype, can cause a serious, potentially fatal, adverse reaction after a transfusion, or a contra-indicated immune response to an organ transplant. The associated anti-A and anti-B antibodies are usually IgM antibodies, which are produced in the first years of