Question

An individual has 'O' blood group if his/her blood sample _______

• A. Clumps only when antiserum A is added
• B. Clumps only when antiserum B is added
• C. Clumps when both antiserum A and antiserum B are added
• D. Does not clump when either antiserum A or antiserum B is added

Answer 1

Answer: (D)

Does not clump when either antiserum A or antiserum B is added

There are 4 types of blood group as per ABO blood group system. These are A, B, AB and O. Person with A blood group has antigen A on its RBC and antibodies B in the blood. Similarly, person with B blood group has antigen B on its RBC and antibodies A in the blood. Person with O blood group has no antigen on its RBC and A and B antibodies in the blood. Person with AB blood group has both A and B antigen on the RBC and no antibodies is present. A person is said to have O blood group when her/his blood sample does not clump when either antibodies A or B is added. This is because, he/she is not carrying any antigen with which antiserum A or B will react and form a clump.

Thus, the correct answer is 'Does not clump when either antiserum A or antiserum B is added.'