The use of the terms “match”, “matching” or a “perfect match” are often misunderstood or misused when referring to a recipient and donor.
A more accurate way of describing the evaluation process is to use the terms, “suitable” and “compatible”. A suitable donor is someone that is healthy enough to donate. A donor is compatible when all the tests are finalized for the recipient and donor and it is shown that the prospective donor is able to donate to their recipient. When people say they are a "match", they usually mean that they are compatible to the recipient.
Generally, a recipient and donor aren't "matched" until they know that the donor is suitable and compatible.
The term “match” references the 6 HLA's (Human Leukcyte Antigens.) Before antirejection medications, 6 out of 6 antigens needed to match in order for the transplant to be successful. The new anti rejection drugs are so effective, that there isn’t a statistical difference in success rates between a zero match and a 5 out of 6 match. Therefore, HLA matching typically is not a factor that determines whether someone is compatible. There is however, a benefit to having a “perfect match,” 6 out of 6 antigens since the life of the transplanted kidney survives significantly longer. (On average, 28 years instead of 18 years for a 0 - 5 match,)
Donor and recipient matching is divided into three distinct areas: blood type matching, tissue type matching, (the HLA referenced above,) and cross matching.
Transplants are being done when donor and recipient have different blood types. A procedure called plasmapheresis on the recipient makes this possible. (Plasmapheresis will be a topic of another blog.)
Cross matching is a very sensitive and final test performed on a kidney donor and their recipient. The basic cross match test involves a mixing of the donors and recipients cells and serum to determine whether or not the recipient of a kidney will respond to the transplanted organ by attempting to reject it. A positive cross match means that the recipient has responded to the donor and that the transplant should not be carried out. A negative cross match means that the recipient has not responded to the donor and therefore transplantation should be safe.
While this language may appear a bit backwards, the cross match is the test indicating a “go” or” no go” for the transplant.
Either way hearing that there's a "match" is usually Great News!!
Harvey Mysel is a kidney transplant recipient and Founder of the Living Kidney Donors Network, a nonprofit organization that offers Workshops and Get-Togethers to educate people in need of a kidney transplant about living kidney donation and helps prepare them to effectively communicate their need to family members and friends. The Living Kidney Donors Network website is: www.lkdn.org and Harvey could be reached at: firstname.lastname@example.org or follow him on Twitter www.twitter.com/harveymysel