During an investigation of a transfusion reaction, what would support a diagnosis of a negative blood group discrepancy?

A diagnosis of a negative blood group discrepancy is supported when there are consistent direct antiglobulin test (DAT) results across samples. This indicates that the patient's antibody response and red blood cell compatibility remain unchanged despite any peculiarities in ABO typing that may arise due to the presence of unexpected antibodies or cold reactive antibodies.

In the context of blood type discrepancies, a consistent DAT demonstrates that the red blood cells are indeed reacting with the anti-human globulin, showing that the cells themselves are not coated with antibodies, which could create confusion in determining blood type. This is crucial because a negative DAT suggests that no alloantibodies are coating the red blood cells, thus aligning with the idea of a discrepancy that does not actually involve an immune response impacting blood group determination.

The other options present potential issues in transfusion fundamentals but do not support the concept of a negative blood group discrepancy. Hemoglobinuria suggests red blood cell destruction, which does not align with maintaining a consistent DAT. Fever and hemolysis indicate a likely transfusion reaction, which contradicts the lack of immune response suggested by a negative discrepancy. Inconsistent ABO typing results point toward potential issues that would require further exploration rather than supporting a negative discrepancy interpretation.