Texas A&M University (TAMU) BIOL206 Introductory Microbiology Lab Practice Exam 1

Type AB blood is considered the universal recipient because individuals with this blood type possess both A and B antigens on the surface of their red blood cells. This presence allows them to accept blood from all other ABO blood types (A, B, AB, and O) without experiencing an immune response. In contrast, other blood types have specific antibodies that would react against antigens present in blood types they are not compatible with. For example, a person with type A blood has anti-B antibodies and cannot receive type B or AB blood without a risk of hemolytic transfusion reaction. Similarly, type B blood contains anti-A antibodies, and type O blood has both anti-A and anti-B antibodies. Hence, individuals with AB blood can safely accept donations from any blood type, making them universal recipients.