What should be done if a mixed-field reaction is seen with anti-A in a type and crossmatch?

In a type and crossmatch setting, a mixed-field reaction with anti-A indicates that there are two distinct populations of red blood cells present, one that reacts with the antibody and one that does not. This type of reaction can suggest the presence of either subtype A or the existence of multiple cell populations, such as in cases of chimerism or recent transfusions.

Retyping with additional tests is the most appropriate course of action in this situation. This further investigation can help in confirming the blood type and identifying the underlying cause of the mixed-field reaction. Additional tests may include using other anti-A reagents or performing further blood group typing methods to achieve a clearer and definitive result, ruling out any complications that could arise from an incorrect blood type assignment.

Using anti-A1 lectin, washing the cells, or doing nothing would not adequately address the potential implications of the mixed-field reaction; these options either overlook the necessary confirmation of blood typing or fail to investigate possible underlying conditions that could affect transfusion safety. Therefore, retyping with additional tests is crucial to ensure patient safety and accurate blood type determination.