Types of Kidney Donation
There are four types of living kidney donation: advanced donation, paired exchange donation, direct donation, and Good Samaritan donation.
Direct donation and Good Samaritan donation are the traditional paths of kidney donation, but are rapidly becoming obsolete in favor of advanced donation and paired exchange. Advanced donation and paired exchange usually lead to better matches and therefore better outcomes or longer lasting kidneys, unless you are a well-matched sibling donor/recipient pair.
The Advanced Donation Program (ADP) is a kidney paired exchange separated in time and the program behind the National Kidney Registry’s Voucher Program.
There are two types of ADP cases:
- Standard Voucher: Short-term cases, where there is only one intended recipient who is in imminent need of a kidney transplant.
- Family Voucher: Long-term cases, where the donor names up to five family members who are currently not in need of a kidney transplant and may never need a transplant. Only one family voucher recipient can redeem their voucher.
If you know someone in need of a kidney, the advanced donation standard voucher is the best choice for you as you get all the protections of Donor Shield and you can donate on your schedule while providing a voucher for the person you know in need of a kidney; they will then receive prioritization for a match through the National Kidney Registry. If you do not know someone in need of a kidney, but would like to donate anyway, the family voucher is the best choice for you as it comes with all of the protections of Donor Shield and allows you to give up to five vouchers to your immediate family members; in case one of them ever needs a kidney, they will be prioritized for a match through the National Kidney Registry.
Both types of ADP cases allow donors to donate their kidney before their intended recipient receives a kidney. Some ADP donors have donated just a few months before their intended recipient was transplanted (standard voucher cases), but others (family voucher cases) have donated 20+ years before their intended recipient is expected to need a transplant with the hope that their intended recipient will never need a transplant.
Paired Exchange Donation
In a paired exchange, a donor will donate their kidney to another recipient in exchange for a compatible kidney for their loved one.
In the example to the right, the first pair, a mother and her son, are incompatible. The second pair, a husband and his wife, are also incompatible. In this exchange, the mother donates to the wife of the second pair and the husband donates to the son in the first pair; this is called a loop. A paired exchange chain begins with a Good Samaritan or voucher donor that donates to the son. The mother then donates to the wife and the husband will donate to someone else with a paired donor in a domino chain as shown in the diagram below under Good Samaritan donation.
Traditionally, paired exchange is for pairs that are incompatible, however, compatible pairs will often enter into a paired exchange to get a donor who is a better match to their paired recipient as a better match usually means the new kidney will last longer.
Direct donation is the original form of organ donation in which the donor generally knows the recipient and donates directly to them. This is the best option if the donor is the recipient’s sibling and/or an excellent match (five- or six-antigen match). Otherwise, paired exchange offers a significantly higher long-term organ survival rate than traditional direct donation.
In order to donate a kidney in a direct donation, donors must:
- Be healthy
- Be blood type compatible
- Pass a cross match
If the donor passes these steps, the donor’s kidney can be transplanted directly into the recipient. One problem with direct donation is that direct donors are often incompatible or poorly compatible with their intended recipients—this means they are not the right blood type or do not pass a cross match test with the intended recipient.
However, a donor can still help their intended recipient get a transplant if they are poorly compatible or incompatible by participating in paired exchange.
Good Samaritan Donation
With Good Samaritan donation, the donor gives to a stranger, which may or may not initiate a chain of transplants. A Good Samaritan may give directly to a stranger on the deceased donor waitlist, but many Good Samaritan donors choose to start chains because it is a way to help more than one person suffering from kidney failure. One chain can facilitate anywhere from two to 30 transplants. Chains revolutionized the paired exchange process by facilitating better donor-recipient matches including some six-antigen matches, which is important because a great match allows the transplanted kidney to last longer.
This type of donation is rapidly disappearing as more and more Good Samaritan donors learn about, and participate in, the Advanced Donation Program’s Family Voucher Program.