Blood Tissue Match Compatibility

[Note: Many websites, books and articles detail the physical process of becoming a living donor. We want to concentrate on the pragmatic, emotional and psychological aspects of the experience, as well as various ethical issues so we'll cover the highlights and provide plenty of links for more information.]

I. Blood type matching. A potential living donor will be relieved of multiple vials of blood used for blood typing and HLA (Human Leukocyte Antigen) typing and matching.

Not all blood types can donate to, or receive an organ from all other blood types. If your blood type and that of the recipient's are incompatible, there are programs available to facilitate Paired Exchanges, which means you and your recipient are matched up with another donor/recipient pair who also have incompatible blood types. Sometimes these exchanges involve multiple donor/recipient pairs.

Here is a list of hospitals with Exchange Programs. This list may not be complete so please check with your local transplant center.

The Alliance for Paired Donation: A private organization founded in Ohio but with partners across the nation to help facilitate paired donations.

Paired Donor Network: 78 transplant centers across the country are members.

Sites are popping up all over the web to facilitate what is known as "Good Samaritan" or "non-directed" living donation, which allow those in need of an organ to advertise for a living donor. These sites operate outside of UNOS/OPTN legal jurisdiction, meaning there is no oversight or guidelines to protect either the recipient or the living donor. In addition, these sites charge a fee to the recipient for listing. Just because a site is 'non-profit' does not mean they aren't taking home a paycheck. If you are interested in donating to a stranger, please contact your local transplant center.

One report states that only 10% of transplant centers will consider a donation from a donor unrelated or unknown to the recipient. Please see our Facts page for the controversy surrounding these sites.

II. HLA Matching

All humans possess six Human Leukocyte Antigens (aka those things that make up our immune system), three from each parent. There are three general groups of HLA: A, B & DR with many subsets of each. The recipient and the potential donor's blood are HLA typed and then compared. The results are given as "X out of 6" match.

While advances in anti-rejection meds have made the degree of match less important, the greater the match, the lower the odds the recipient's body will reject the organ.

To view the latest graft (organ) survival rates based on HLA mismatch from OPTN data:

Click here.
Click 'data' on the main menu.
View Data Reports (second from the top)
'National Data'
Select Category: Survival
Step 2: Survival by HLA mismatch (right-hand column, second from the top)

More on survival rates by HLA Matching.

Indepth article on HLA matching and graft survival in kidney transplantation.

III. Crossmatch

A very small amount of the potential donor's blood is mixed with the recipient's blood to determine if the recipient's antibodies will attack the potential donor's blood, and subsequently, any organ from that donor. A "negative crossmatch" indicates the donation can take place.

More information from the University of Michigan Medical Center.

If blood type is compatible, crossmatch is negative and HLA achieves minimum level, the potential living donor will have to decide if s/he wishes to submit herself to two days of diagnostic testing, the purpose of which is to A. determine if the donor is healthy enough to survive the procedure and live a normal life post-donation, and B. if the prospective donor organ is healthy enough to keep the intended recipient alive.

Many prospective donors who find themselves unable to continue the process experience sadness or even profound depression, anger, disappointment and helplessness. This is completely normal. It is important to remember that no one blames you for being unable to donate, and your willingness to give a (literal) part of yourself to help someone else is magnificent and admirable. While there are very few, if any, real life support groups for living donors, there are forums and email lists online that, hopefully, can provide you with consolation, information, reaffirmation and respect.

More to come.....

Glomerular Filtration Rate - in layperson's terms, it's how kidney function/effectiveness is measured.

A 2008 comparison of multislice CTA and gadolinium-enhanced MRA found the same degree of accuracy in the characterization of renal vasculature (in other words, the blood vessels leading into and out of the kidneys)