Fetal Blood Group Genotyping Arrives in Ontario: What Transfusion Medicine and Prenatal/Newborn Care Teams Need to Know
Kathryn Millar, BORN, Prenatal Screening Ontario
Ontario health-care providers will soon have access to two innovative, publicly funded fetal blood group genotyping tests that can improve pregnancy management, reduce unnecessary interventions, and support more precise transfusion medicine decisions.
Beginning September 21, 2026, health-care providers will be able to order two new publicly funded, referred-out blood tests for eligible pregnant women/individuals living in Ontario:
- Fetal RHD Screening – Identifies the fetal RhD status in RhD negative pregnancies.
- Alloimmunized Fetal Blood Group Genotyping (Allo-FBGG) – Determines fetal antigen status in pregnancies with anti-D, anti-C, anti-c, anti-E, and/or anti-K (Kell) antibodies.
These new tests represent a major step toward more personalized prenatal care and have important implications for obstetrical care providers and Transfusion Medicine Laboratories (TMLs).
What Is Changing?
- Targeted RhIG administration only for pregnancies identified to be carrying an RhD-positive fetus.
- Impact: Up to 40% reduction in RhD immune globulin (RhIG) use.
- Allo-FBGG – guided monitoring and management for pregnancies with anti-D, anti-C, anti-c, anti-E, or anti-K (Kell) antibodies.
- Impact: Reduction in unnecessary monitoring and management for pregnancies not at risk of hemolytic disease of the fetus and newborn.
Considerations for Transfusion Medicine Laboratories and Labour and Delivery
Fetal RHD screening introduces an important practice change for Transfusion Medicine Laboratories.
- Review Fetal RHD screening results in OLIS or other provincial clinical viewers to support RhIG dispensing decisions during the current pregnancy.
- Fetal RHD screening reports will indicate whether RhIG is recommended based on the fetal result.
- Postnatal cord blood testing practices remain unchanged and should continue according to existing policies and procedures.
- Fetal RHD screening results may be used to support postpartum RhIG assessment and administration.
- Report discrepancies between Fetal RHD/Allo-FBGG results and postnatal cord blood testing results to the testing laboratory to support quality assurance.
Resources and Clinical Support
Health-care provider and patient resources are available through Prenatal Screening Ontario (www.prenatalscreeningontario.ca). Resources for TMLs are available in the perinatal section of the ORBCoN website (https://transfusionontario.org/en/category/perinatal/).
Canadian Blood Services (CBS) will perform Fetal RHD screening, while Sinai Health will perform Alloimmunized Fetal Blood Group Genotyping (Allo-FBGG) testing for eligible pregnant individuals in Ontario.
Fetal RHD screening and Allo-FBGG will be clinically available across Ontario beginning September 21, 2026.