Which description correctly defines Type AB blood?

Which description correctly defines Type AB blood?

• A. Has both A and B antigens on red cells and no antibodies against A or B
• B. Lacks A and B antigens and has anti-A and anti-B antibodies
• C. Has A antigen only on red cells
• D. Has B antigen only on red cells

Answer: (A)

Blood type depends on which antigens sit on the surface of red blood cells and which antibodies are present in the plasma. Type AB has both A and B antigens on the red cells, and it has no anti-A or anti-B antibodies in the plasma. That combination means the cells display both marker types, but the plasma won’t attack those markers if exposed to A or B antigens from another source. This is why this description fits AB best: the presence of both A and B antigens on the cells and the absence of antibodies against A or B in the plasma. The other descriptions match other blood types: lacking A and B antigens with anti-A and anti-B antibodies describes type O; having A antigen only describes type A; having B antigen only describes type B.

Blood type depends on which antigens sit on the surface of red blood cells and which antibodies are present in the plasma. Type AB has both A and B antigens on the red cells, and it has no anti-A or anti-B antibodies in the plasma. That combination means the cells display both marker types, but the plasma won’t attack those markers if exposed to A or B antigens from another source. This is why this description fits AB best: the presence of both A and B antigens on the cells and the absence of antibodies against A or B in the plasma. The other descriptions match other blood types: lacking A and B antigens with anti-A and anti-B antibodies describes type O; having A antigen only describes type A; having B antigen only describes type B.