A new type of blood test is giving doctors better tools to protect babies from hemolytic disease of the fetus and newborn (HDFN), according to a review published recently in Current Opinion in Hematology.
HDFN can occur when a mother’s immune system attacks her baby’s red blood cells (RBCs), leading to severe anemiaAnemia A condition that occurs when the body doesn’t have enough healthy red blood cells to carry oxygen to its tissues. In HDFN, anemia occurs when maternal antibodies destroy fetal red blood cells. and other health problems. The technology, called RBC genotyping, looks at a person’s genetic code to determine their blood type in great detail.
This technology can find differences in blood proteins, called antigensAntibody A protein made by the immune system that recognizes and attacks foreign substances, such as bacteria, or in HDFN, fetal red blood cells carrying incompatible antigens., that may not show up in standard lab tests. This helps doctors identify when a pregnant woman and her baby have blood type differences that could cause HDFN, and take steps early to prevent harm.
“RBC genotyping is being increasingly used in patient care, offering solution in cases where serological typing is insufficient or yields discrepant results,” the authors wrote. “As more and more variants are discovered, studies to determine their antigenicity are required to understand the clinical significance of the novel variants.”
Read more about the testing and diagnosis of HDFN
RBC genotyping is especially helpful when regular blood typing gives unclear results, such as in patients who have had recent transfusions, stem cell transplants, or certain medications that interfere with testing. It can also be critical for people who have rare blood types or multiple antibodiesAntibody A protein made by the immune system that recognizes and attacks foreign substances, such as bacteria, or in HDFN, fetal red blood cells carrying incompatible antigens. that make finding compatible blood difficult.
Current genotyping tests can look at dozens of genetic markers across many blood groups. More advanced versions, including next-generation DNA sequencing, can find even rarer variations and spot complex genetic changes that may affect blood compatibility. These improvements mean clinicians can match blood more precisely for transfusions and make more accurate decisions during pregnancy.
In the case of HDFN, this technology allows for better prenatal risk assessments. If a mother is found to be at risk, doctors can closely monitor the baby and give preventive treatments like RhRh factor A protein or antigen found on red blood cells. When an Rh-negative mother carries an Rh-positive fetus, her immune system may make antibodies that attack the fetus' red blood cells. immune globulin to reduce the chance of anemia. The goal is healthier pregnancies, safer births, and fewer complications for newborns.
Experts say this type of testing is becoming more common in hospitals and blood centers. As research continues, scientists are working to understand how newly discovered blood type variations affect health, with the hope of making blood transfusions and pregnancy care even safer in the future.
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