A new case study published in the Asian Journal of Transfusion Science underscores the importance of accurately identifying rare blood antibodies in pregnancy for the proper diagnosis and management of hemolytic disease of the fetus and newborn (HDFN).
The case involved a 24-year-old RhD-negative woman in her third pregnancy. At 36 weeks, she delivered a baby girl who was RhD-positive. The newborn developed severe jaundice and anemia, and was treated with both phototherapy and an exchange transfusion, a treatment in which the infant’s blood is replaced to reduce high levels of bilirubin, the substance responsible for jaundice.
Testing revealed the presence of antibodies that initially appeared to be a mix of anti-D, anti-C and possibly anti-G. Anti-G often looks just like anti-D and anti-C in lab tests, but the distinction is important, as it could affect treatment decisions.
In this case, if the mother had only anti-G, she would still need Rh immunoglobulin (RhIG) after delivery to prevent sensitization to anti-D in the future. But if she already had true anti-D, RhIG would no longer help. Getting that distinction wrong could mean either giving an unnecessary treatment or skipping a treatment that could protect future pregnancies.
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To make an accurate diagnosis, the woman’s medical team used a stepwise adsorption and elution technique (a process that separates antibodies using specific red blood cells). This approach avoided expensive or complex methods, such as enzyme treatment or acid elution, making it practical for hospitals with limited resources. The results determined that she had anti-D and anti-C, but not anti-G. This meant that she did not need RhIG postpartum, since her immune system was already producing anti-D.
The researchers pointed out that misidentifying antibodies also have implications beyond clinical care, including unnecessary questions about paternity or past transfusions.
The study authors say the report reinforces the need for precise antibody testing in all suspected cases of HDFN – and while advanced laboratories have developed sophisticated methods for teasing apart these antibodies, simpler, cost-effective approaches are still possible.
“While employing specialized methods can enhance the detection of IgG antibodies, resource-constrained settings should not deter one from conducting testing using untreated cells and simple heat elution to differentiate between anti-G and anti-C/D antibodies, as it is documented in studies that IgG antibodies can be detected through heat elution,” the researchers concluded.
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