Identification of Anti-G in Pregnant Women with RhD Negative Blood: The First Case in Korea

Abstract

Anti-G positivity can be misinterpreted as the presence of anti-D or-C antigen in an antibody identification test, as this antibody is known to show agglutination to D or C antigen-positive red cells. Correct identification of anti-G is important in pregnant women, as prenatal care or the need for RhIG administration can vary between anti-D and-C versus anti-G cases. We recently encountered a D-negative case with suspected anti-D and-C, which was ruled out by adsorption and elution tests, and ultimately confirmed the presence of anti-G. The pregnant woman was a 33-year-old patient with cde Rh phenotype with a previous history of spontaneous abortion, followed by administration of RhIG. The spouse's Rh phenotype was CDe. Initial antibody identification test showed 2＋ positivity to C (homozygotes and heterozygotes) and trace to 1＋ positivity to D. Upon additional adsorption and elution with R0r (cDe/cde) and r'r (Cde/ cde) red cells, we identified the antibody present in the patient's serum as anti-G. The patient is currently under close follow-up monitoring for anti-G titer using antibody titer testing with both CDe and CcDEe red cells. Periodic fetal cerebral Doppler examination is being carried out without evidence of fetal distress.