Health Information and Tools > Kidney Transplant > Living Kidney Donation > Testing >  Tissue Typing and Crossmatch
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Living Kidney Donation

Tissue Typing and Crossmatch

Tests for all potential donors

Tissue Typing

This is a blood test that looks for antigens called human leukocyte antigens (HLA). Your blood is tested to see if your genetic make-up is close to the recipient’s. A person gets some from their mother and some from their father. Blood relatives like parents and siblings may have a similar genetic make-up. The lab looks at the HL​A antigens and tries to match them between you and the recipient. There doesn’t need to be a perfect match, but it is better for a more successful outcome.

An antigen is a small substance like a protein or molecule that makes the body form antibodies against it. An antigen causes an immune response in the body.


The crossmatch checks if the recipient’s immune system may react to your donated kidney. The test mixes a sample of your blood and the recipient’s blood together to see if there’s a reaction. It can take several weeks to get this result.

A negative crossmatch means there’s no reaction between your blood and the recipient’s blood. This means they are compatible and there’s a lower chance the kidney will be rejected.

A positive crossmatch means that your blood and the recipient’s blood don’t match or are not compatible, and your kidney is likely to be rejected.

This blood test is done during your evaluation and again within 1 month of your surgery to make sure that the result hasn’t changed.

If you and your recipient are not compatible but you still want to donate your kidney, you might consider the Kidney Paired Donation (KPD) Program. The donor evaluation stays the same. ​

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