What is the likely blood group of a patient with the following typing results: anti-A: 0, anti-B: 0, anti-A,B: 2+, A1 red cells: 2+, B red cells: 4+, Ab screen: 0?

The blood typing results given indicate that the patient has no reactions with anti-A and anti-B, indicating the absence of A and B antigens. However, the presence of a reaction with A1 red cells suggests that the patient has some form of A antigen expression, but not the typical A or B antigens that would elicit a stronger reaction with anti-A.

The presence of a 2+ reaction with A1 red cells and a 4+ reaction with B red cells suggests that the patient's blood does not have the conventional A antigen found in group A individuals but might have some variant of the A antigen, such as A3, Ax, or Ay, which can react weakly with anti-A serum. The Ab screen being 0 suggests that there are no unexpected antibodies present that could complicate the interpretation of the ABO grouping.

This leads us to the conclusion that the patient likely has an Ax type. In this case, the presence of anti-A1 could be considered, as the blood group reacting weakly could lead to the development of this atypical antigen, resulting in the atypical response when A1 red cells are tested.

Thus, interpreting the blood type shows that the patient has a Group Ax, which is why this response is