Which blood type has B antigens and anti-A antibodies?

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

Answer: (C)

In the ABO system, red blood cells carry specific surface antigens (A or B), and the plasma contains naturally occurring antibodies against the other antigen. The type that has B antigens on the cell surface and anti-A antibodies in the plasma is the one described here. That means it would react to A antigens but not to B antigens, and its plasma would attack cells with A antigens.

To contrast: a type with A antigens would have anti-B antibodies; a type with both A and B antigens (AB) has no anti-A or anti-B antibodies; and a type with neither antigen (O) has both anti-A and anti-B antibodies.