Britannica Sources used in this answer

How does a donor-recipient crossmatch test help prevent transplant rejection?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Kidney transplant — transplant British surgeon Andrew Ready flushing a donated kidney during a transplant at Queen Elizabeth Hospital, Birmingham, England, 2006.

A donor-recipient crossmatch test is a critical final safety measure performed before a transplant to prevent hyperacute rejection, which is an immediate and irreversible immune attack on the donor organ.12

This test involves mixing the recipient’s serum—which may contain pre-existing antibodies—with the potential donor’s lymphocytes. These antibodies can develop in a patient due to prior blood transfusions, previous transplants, or pregnancy. If the recipient has these pre-existing antibodies that recognize the donor’s antigens, the antibodies will attack the donor cells during the test.12

A positive crossmatch result indicates that the recipient’s immune system is primed to rapidly destroy the donor tissue, which typically contraindicates the transplant to avoid a catastrophic, immediate rejection. By identifying this incompatibility beforehand, medical professionals can prevent the implantation of an organ that the recipient's body would likely reject within minutes or hours.12