Carbohydrate antigenic determinants containing a glycosidically linked bridging arm are synthesized and coupled to carrier molecules to form artificial antigens, and to solid supports to form immunoabsorbants. These artificial antigens are used to detect antibodies to the carbohydrate haptens, and to raise antisera specific for the carbohydrate antigenic determinants. The immunoabsorbants are used to purify or remove antibodies to the carbohydrate haptens. Specific examples are given to the synthesis of the Lewis-a, Lewis-b, B, and H(O) blood group antigens; to the preparation of antisera to these artificial antigens, and to the preparation of immunoabsorbants specific for antibodies to these antigens.