Anti-Rga: identifying serologic characteristics

Anti-Rga is a rare alloantibody that is difficult to recognize and identify. Although posing no apparent transfusion risk itself, it can mask the presence of underlying alloantibodies which could be transfusion risks. The five patients reported here demonstrate the serologic findings characteristic of anti-Rga. Known Rg(a-) test cells and multiple "target cells" in neutralization studies are needed to demonstrate partial neutralization findings and to detect underlying alloantibody. Other observations were that clotted samples of red cells retained Rga reactivity for 49 days, whereas EDTA-anticoagulated red cell samples lost such reactivity after 13 days. Frozen red cells tested within hours of deglycerolization showed excellent Rga reactivity.