Which blood type has neither A nor B antigens?

Which blood type has neither A nor B antigens?

• A. Type O
• B. Type A
• C. Type B
• D. Type AB

Answer: (A)

ABO blood groups are determined by which carbohydrate antigens are present on the surface of red blood cells and which antibodies are circulating in the plasma. The type that has neither A nor B antigens is the one where the red cells lack both of these surface markers. Because this type synthesizes antibodies against A and against B in the plasma, it would react with donor cells that carry A or B antigens if exposed. This is why this type can be donated to all other types in RBC transfusions, while it can only receive from its own type. The other types have at least one of the antigens on their cells: A has A antigen, B has B antigen, and AB has both A and B antigens.

ABO blood groups are determined by which carbohydrate antigens are present on the surface of red blood cells and which antibodies are circulating in the plasma. The type that has neither A nor B antigens is the one where the red cells lack both of these surface markers. Because this type synthesizes antibodies against A and against B in the plasma, it would react with donor cells that carry A or B antigens if exposed. This is why this type can be donated to all other types in RBC transfusions, while it can only receive from its own type. The other types have at least one of the antigens on their cells: A has A antigen, B has B antigen, and AB has both A and B antigens.