Tests for kidney donors

Blood Type. The first step is to determine your blood type. There are four blood types, designated by the presence or absence of two antigens—the A antigen and the B antigen. Blood type A means you have the A antigen. Type B means you have the B antigen. Type AB means you have both antigens. Type O means you have neither antigen.

You must have a blood type compatible with the recipient or you will not be able to donate. Here is who can donate to whom:

Type A can donate to types A and AB.
Type B can donate to types B and AB.
Type AB can donate to type AB.
Type O can donate to types A, B, AB, and O.


If you and your potential recipient are not of the same blood type, there are two things you can consider. One option is called "paired exchange." Paired exchange involves finding another donor-recipient pair who have incompatible blood types but your blood type is compatible with the other recipient, and the other donor's blood type is compatible with your potential recipient's blood type. In that situation, you donate to the other recipient, and the other donor donates to your recipient. This web page illustrates how paired exchange works.

The other option is called "plasmapheresis." Plasmapheresis involves the transplant recipient undergoing removal of the spleen and a special medical process that removes the blood's incompatible antigens. With removal of the recipient's antigens, the donor is able to donate.


Tissue Type. A second test of compatibility looks at the match of human leukocyte antigens (HLA). There are many different kinds of antigens, but there are three categories assessed for kidney donation, designated HLA-A, HLA-B, and HLA-DR. You inherit one set of these three antigens from each parent giving you a total of six HLAs.

Your antigens are determined by drawing blood and testing it. A similar test is run for the recipient, and the antigens are compared. The closer the match the better because the recipient is less likely to reject the donated organ. You might hear of a "six-of-six" match (all donor and recipient antigens match) or a "half match" (three of the six antigens are the same) or a "zero match" (none of the antigens matches).

There was a time when tissue compatibility was important. However, the development of more effective anti-rejection drugs has reduced the importance of the HLA match. In fact, some transplant teams ignore tissue typing. Therefore, even if your degree of matching with the donor is relatively low, you may still be considered for donation.



http://www.aarexindia.com/kidney.asp

www.livingdonorsonline.org/kidney/kidney4.htm