blood group  blood group, Human red blood cells (4,000×
magnification).Micro Discovery/Corbisclassification of blood
based on inherited differences (polymorphisms) in antigens on
the surfaces of the red blood cells (erythrocytes). Inherited
differences of white blood cells (leukocytes), platelets
(thrombocytes), and plasma proteins also constitute blood
groups, but they are not included in this discussion.
Historical background        Major human blood group systems
system date of ABO 1901 A1, A2, B, H MNSs 1927 M, N, S, s P 1927
P1, P2 Rh 1940 D, C, c, E, e Lutheran 1945 Lua, Lub Kell 1946 K,
k Lewis 1946 Lea, Leb Duffy 1950 Fya, Fyb Kidd 1951 Jka, Jkb
Diego 1955 Dia, Dib Yt 1956 Yta, Ytb I 1956 I, i Xg 1962 Xga
Dombrock 1965 Doa  The importance of antigens and antibodies
Chemistry of the blood group substances     Methods of blood
grouping  Identification of blood groups       Coombs test  When
an incomplete antibody reacts with the red cells in saline
solution, the antigenic sites become coated with a