When you need a kidney transplant, finding the best match can mean a more successful transplant. The better the match between the donor and recipient, the longer the transplanted kidney can last. How Does the NKR Find the Best Donor-Recipient Match for Kidney Transplants? Traditionally, kidney transplant matches were measured by an HLA match score from zero to six, with six being the best. HLA scores are generally based on A, B and DR antigens.
Except in cases of identical twins and some siblings, it is rare to get a six-antigen match between two people, especially if they are unrelated. Kidneys are very successfully transplanted between two people with no matching antigens. A person can make antibodies against another person’s HLA antigens.
At five years those numbers are 78.7% for 6/6 and 65.6% for 0/6. SRTR’s 2010 annual report shows a 10-year graft survival of non-extended criteria, deceased donor kidneys of 53.7% for 6/6 and 43.8% for 0/6. For living donor kidneys, the SRTR 2010 report shows a 10-year graft survival rate of 74.6% (6/6) vs 55.2% (0/0).
Then, what are the chances of being a kidney donor match? Siblings have a 25% chance of being an "exact match" for a living donor and a 50% chance of being a "half-match." Donor compatibility is established through blood tests that look for matching blood types and antigens. The overall health of the potential donor is also of critical importance.
Living donor programs allow a relative or a compatible unrelated donor (such as a spouse or friend) to donate a kidney. Siblings have a 25% chance of being an "exact match" for a living donor and a 50% chance of being a "half-match." Donor compatibility is established through blood tests that look for matching blood types and antigens.
A 6-antigen (or “perfect”) match is the single best match that can occur between a donor and recipient. Siblings who have the same mother and father share this ideal match 25% of the time. Six-anitgen matches can occur among the general population, but it is rare. Regardless of the match, a kidney recipient must take anti-rejection drugs for the rest of his or her life to prevent the immune system from rejecting the foreign kidney.
The United States is divided into 11 regions and 58 local Organ Procurement Organizations (OPO)s, which are areas used to find matches for transplant. For example, if a kidney becomes available, UNOS will first try to find a match in the OPO where the kidney is being donated. If no match is found there, UNOS will search within the larger region.
The chance of a perfect or six-antigen match between two unrelated people is about one in 100,000. Many times in kidney transplants there are half matches or less and the transplants are still successful.