During ABO testing, if a patient’s serum shows A1 cells 4+ and B cells 2+, what should be done to resolve the discrepancy?

In this scenario, where a patient’s serum demonstrates a strong reaction (4+) with A1 cells and a weaker reaction (2+) with B cells, it suggests a discrepancy in the expected ABO testing results. The most effective approach to resolve this discrepancy involves understanding the potential presence of anti-A1 antibodies in the patient's serum.

By performing an antibody screening procedure at immediate spin using group O cells, the laboratory can effectively identify if there are unexpected antibodies that may account for the weaker reaction with B cells. Group O cells are universal donors lacking A and B antigens, meaning any unexpected antibodies will react, providing insights into possible anomalies.

This procedure helps to clarify whether the weaker reaction with B cells is due to an underlying antibody that is not expected based on the patient’s blood type. It also ensures that the testing is done quickly (immediate spin) to expedite the resolution process.

The other options are less direct or may not adequately address the discrepancy. Drawing a new sample may not yield different results and could delay necessary clinical decisions. Testing with A2 cells and using anti-A1 lectin would specifically target the presence of anti-A1 antibodies, but it may not fully resolve the broader picture of potential antibodies. Repeating the antigen grouping with washed