Which procedure would best resolve the discrepancy in the maternal and infant blood type results indicating a possible low-prevalence antigen?

Eluting the antibody and testing with the father's red cells is the best procedure to resolve the discrepancy between the maternal and infant blood type results that suggests a possible low-prevalence antigen. This approach addresses the possibility that the mother has developed an antibody towards an antigen that is present in the father's red blood cells but may not be a common antigen in the general population or in standard typing cells.

When a discrepancy arises, especially in cases where there is suspicion of low-prevalence antigens, it is important to test with the father's red cells. This allows for the identification of specific incompatibilities that may exist between the maternal serum and the paternal genotype. If the low-prevalence antigen is present on the father's red blood cells, the maternal serum may demonstrate an antibody that reacts specifically with those paternal cells.

In contrast, other options have limitations. Testing with A, B, and O cells, for example, does not specifically address the potential for low-prevalence antigens because these cells are standard and may lack the rare antigens in question. Eluting the antibody followed by testing with a routine panel may similarly miss specific interactions relevant to the parents' unique genotypes. Lastly, testing maternal serum with the baby's red cells might not provide clarity about