Investigative tests on the father depend on which maternal antibodies are present.
1. Mother has anti-D
- ABO and Rh typing with anti-D, -C, -E, -c,-e to determine probable Rh genotype* to predict the chance the fetus has of being Rh positive and affected by HDFN.
- Test for weak D if initial Rh typing appears to be D-negative.
* For D+ fathers, the probable Rh genotype can be determined using serologic tests, i.e., DCEce typing to determine if the father is homozygous or heterozygous for D.
2. Other maternal clinically significant antibodies
- Phenotype father for the corresponding antigen and its antithetical antigen (e.g., K and k).
