Glycophorins A and B are major sialoglycoproteins expressed across the surface of the human erythrocyte membrane and contain the antigenic determinants that define the MNS blood group system.¹ The high sialic acid content of glycophorin A contributes to the generation of a net negative surface charge across erythrocyte membranes that minimizes interactions between red blood cells and prevents their aggregation.  Anti-glycophorin A has utility in identifying cells of the erythroid lineage.²