A    A    A

Blood Group

Sponsored Links

The blood of the human being is classified into various groups depending upon various features. There are about 600 different blood group systems but only two blood group systems such as, ABO and Rh are of major importance..1

ABO blood group system consists of four main blood groups based on the presence or absence of two antigens. These antigens are A and B. These four blood groups are A, B, AB and O. The antigens are under the control of three genes A, B and O; these can be Rh negative or positive.2

When a person is said to be of A-Positive (+ve) blood group, it means that that person has the “A” group from the ABO system and also has the Rh antigen on the red cell surface. On the other hand, a person is said to be of B-Negative (-ve) blood group when he has the “B” antigen on the cell surface but not the Rh antigen (see Table 1).2

Table 1: Relationship between antigens A and B and their corresponding antibodies

Name of blood group
Antigens present in red cells
Antibodies normally present in serum
Anti-A and Anti-B


Blood group can be easily assessed by simple test and are useful:

  • To know the blood group before blood transfusions
  • To prevent Rh incompatibility in pregnancy
  • Medico-legal cases
  • Investigations in case of paternity disputes
  • Blood group antigens also help in cell recognition


Written by Healthplus24 team
Date last modified: May 24, 2011