Isolating anti-D, anti-C, and anti-G in immunohematology: a method comparison

G is present on virtually all red blood cells expressing either D or C; thus, identification of anti-G, anti-D, and anti-C in a patient’s plasma can be challenging. While identification of anti-G is usually of little clinical significance, it becomes increasingly important in the context of prenatal care. Proper antibody differentiation is necessary to determine candidacy for Rh immune globulin administration to prevent anti-D immunization during pregnancy. We conducted an analytical experimental study of 18 plasma samples from donors and patients with apparent anti-D and anti-C upon initial antibody identification. Samples were tested in duplicate using two established anti-G differentiation methods. Method A consisted of sequential adsorption and elution techniques, and Method B consisted of double adsorption and elution techniques. Of the 18 samples obtained, 14 fit the criteria for inclusion in this study. Both methods successfully identified anti-G and anti-D when present. Method A failed to identify anti-C in one sample. Our results generated a percent positive agreement of 92.9 percent with a 95 percent confidence interval of 68.5–98.7. Our findings demonstrated that Method B detected more antibodies than Method A and allowed for a reduction in testing time, making it the preferred method in this study.