In cases like those of Patient A.D. two main serologic questions need to be answered:
- Are the reactions due to passive anti-D from RhIg or due to active (immune) anti-D?
- Are there other antibodies that need to be excluded
Unfortunately, since there is no way to definitively differentiate immune from passive anti-D, certain assumptions are usually made.
Most laboratories first confirm that, as expected, only anti-D is being detected.