Several screening methods are available to detect FMHs that require additional RhIG, including:
- Rosette method
- Commercial fetal bleed screening tests
- Gel agglutination fetal cell screening technique
Note: The rosette test may be falsely positive if the mother is weak-D positive and may be falsely negative if the baby is weak-D positive.
The rosette method, commonly used by many laboratories, will be briefly reviewed.