ABO type AB has which combination of antigens and antibodies?

ABO type AB has which combination of antigens and antibodies?

• A. Antigen A only and antibodies against B
• B. Antigen B only and antibodies against A
• C. Both antigens present and no antibodies
• D. No antigens and both antibodies

Answer: (C)

This question tests how ABO antigens and antibodies are distributed on red blood cells and in plasma. People with type AB have both A and B antigens on the surface of their red blood cells, and their plasma contains no antibodies against A or B. That combination—two antigens present, no corresponding antibodies in the plasma—fits AB blood type precisely. In contrast, type A has the A antigen with anti-B antibodies in the plasma, type B has the B antigen with anti-A antibodies, and type O has neither A nor B antigens but has both anti-A and anti-B antibodies in the plasma.

This question tests how ABO antigens and antibodies are distributed on red blood cells and in plasma. People with type AB have both A and B antigens on the surface of their red blood cells, and their plasma contains no antibodies against A or B. That combination—two antigens present, no corresponding antibodies in the plasma—fits AB blood type precisely.

In contrast, type A has the A antigen with anti-B antibodies in the plasma, type B has the B antigen with anti-A antibodies, and type O has neither A nor B antigens but has both anti-A and anti-B antibodies in the plasma.