If the mother has a clinically significant antibody, routine serologic tests done on the newborn include
- ABO and Rh
- Direct antiglobulin test (DAT)
If the newborn's DAT is positive, these procedures should be followed:
- Elution of newborn's red cells to prepare an eluate containing the sensitizing antibody (unless assessed to be passive anti-D from RhIg*)
- Antibody identification using eluate
Antibody in the eluate should correspond to at least one antibody found in the maternal serum.
* The exception is a positive DAT in a newborn whose mother received RhIg antenatally and who has anti-D at delivery. If other maternal antibodies have been excluded, the positive DAT is assumed to be from RhIg and no elution is performed.