Based on the forward typing results (Anti-A 4+, Anti-B 0), what is the predicted blood group?

Based on the forward typing results (Anti-A 4+, Anti-B 0), what is the predicted blood group?

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

Answer: (A)

Forward typing checks which antigens are on the red cells by exposing them to anti-A and anti-B sera. If the cells agglutinate with anti-A but not with anti-B, that means the A antigen is present and the B antigen is absent. So the blood type is A. The other patterns would be different: agglutination with both anti-A and anti-B would indicate AB, with neither would indicate O, and agglutination with anti-B only would indicate B. In this case, strong A antigen and no B antigen point to group A.

Forward typing checks which antigens are on the red cells by exposing them to anti-A and anti-B sera. If the cells agglutinate with anti-A but not with anti-B, that means the A antigen is present and the B antigen is absent. So the blood type is A. The other patterns would be different: agglutination with both anti-A and anti-B would indicate AB, with neither would indicate O, and agglutination with anti-B only would indicate B. In this case, strong A antigen and no B antigen point to group A.