Question

Why is tissue typing necessary before a kidney transplant?

Answer 1

To determine the compatibility of antibodies of donor and recipient. 
Tissue typing is a type of blood test that matches the antibodies that the donor and recipient share. 
An ideal result would be a match of 6 out of 6 antigens.

Answer 2

Answer:

The tissue typing is a blood test that matches the number of antigens on the surface of recipients and donor blood surface. The main aim of matching a tissue of donor kidney with the person who is seeking transplantation is the identification of a Human Leukocyte Antigen. It is a marker that tells the possibility of the organ to accept organs from another person body.

If the tissue type of the donor and the recipient do not match then the body immune system identifies it as foreign tissue and try to kill it or reject it. That is why tissue typing is done to prevent rejection after transplantation.