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, ie, DCEce typing to determine if the father is probably homozygous or heterozygous for D.
2. Other maternal clinically significant antibodies
- Phenotype father for the corresponding antigen and its antithetical antigen (eg, K and k)