ABO blood group system alleles in white individuals of the ABO gene that produce one's blood type: The same study also identified 18 rare alleles, which generally have a weaker glycosylation activity. People with weak alleles of A can sometimes express anti-A antibodies, though these are usually not clinically significant as they do not stably interact with the antigen at body temperature. Cis AB is another rare variant, in which A and B genes are transmitted together from a single parent. The distribution of the blood groups A, B, O and AB varies across the world according to the population. There are also variations
Intraoperative blood salvage As a result, the global medical community has increasingly moved from allogenic blood (blood collected from another person) towards autologous infusion, in which patients receive their own blood. Another impetus for autologous transfusion is the position of Jehovah's Witnesses on blood transfusions. For religious reasons, Jehovah's Witnesses will not accept any allogeneic transfusions from a volunteer's blood donation, but may accept the use of autologous blood salvaged during surgery to restore their blood volume and homeostasis during the course of an operation, although not autologous blood donated beforehand. There are other religious/ non-religious individuals besides Jehovah's Witnesses that accept Intraoperative