ABO Blood Group Compatibility

ABO blood group compatibility is important for safe blood transfusions. People have specific antigens (markers) called A and B on their red blood cells, and their plasma (the liquid part) may contain antibodies that attack incompatible antigens. A person with type A blood has A antigens and anti-B antibodies, so they can receive type A or O blood but not B or AB. Type O is universal donor because it has no A or B antigens, reducing the risk of reaction. For safety, blood transfusions must match the donor’s and recipient’s ABO types to prevent immune reactions that can damage red blood cells.