<haematology> An inherited feature on the surface of the red blood cell. A series of related blood groups make up a blood group system such as the ABO system or the Rh system.

Erythrocytic allotypes (or phenotypes) defined by one or more cellular antigenic structural groupings under the control of allelic genes. Blood groups, especially for man, are identified by agglutinins supported by specific human or animal antisera and by lectins extracted from certain plants.

See: blood group antigen.

(25 Jun 1999)