Biology - Blood Group



  • Based on the presence and absence of antibodies, the blood is classified into different groups.

  • Further, while classification, the presence and absence of the inherited antigenic substances also considered.

Blood Group
  • The types of blood groups are inherited and represent contributions from both the father and the mother.

ABO Blood Group System

  • In human blood, usually, there are two antigens and antibodies.

  • The two antigens are antigen A and antigen B.

  • The two antibodies are antibody A and antibody B.

  • The antigens are remaining in the red blood cells, whereas the antibodies are found in the serum.

  • Based on the antigen property, the blood group of all human beings can be classified as −

    • Blood Group A − antigen A and antibody B

    • Blood Group B − antigen B and antibody A

    • Blood Group AB − antigen A and antigen B and no antibody

    • Blood Group O − no antigen, but antigen A as well as antibody B

  • Consideration of the ABO system is the most imperative while transfusion of human blood.

  • The ABO blood group systems were first discovered by Karl Landsteiner in 1901.

Rh Blood Group System

  • The Rh system (the meaning of Rh is Rhesus) is another significant blood-group system. It is very important to match Rh system while blood transfusion.

  • Rh antigen first studied in Rhesus monkeys; therefore, its name is given Rh factor/system.

  • The person who does not have Rh antigen is known as Rh negative (Rh-ve) and the person who has the Rh antigen is known as Rh positive (Rh+ve).

Blood Transfusion

  • Based on the above discussed two blood grouping system (i.e. ABO and Rh), the following table illustrates the possibilities of blood transfusion among different blood groups −

Recipient Donor
O- O+ A- A+ B- B+ AB- AB+
O- Yes No No No No No No No
O+ Yes Yes No No No No No No
A- Yes No Yes No No No No No
A+ Yes Yes Yes Yes No No No NO
B- Yes No No No Yes No No No
B+ Yes Yes No No Yes Yes No No
AB- Yes No Yes No Yes No Yes No
AB+ Yes Yes Yes Yes Yes Yes Yes Yes


  • Based on the blood transfusion table given above the blood group O- is the universal donor, which can give blood to the person of any blood group.

  • Secondly, the blood group AB+ is the universal recipient, as it can accept blood from the person of any blood group.