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Kidney Paired Donation Program

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Dr. Sandip Kapur interacts with a patient.

Frequently Asked Questions

How does Kidney Paired Donation work?

People interested in participating in Kidney Paired Donation (whether donors or recipients, incompatible or compatible) are entered into a Kidney Paired Donation database. The information entered into the database includes their blood type, HLA antigen typing, and other basic medical information.

Sophisticated computer software designed to match up donors and recipients within a Kidney Paired Donation registry is run on a regular basis, usually anywhere from daily, to once per week to once per month, depending on the number of donors and recipients entered into the registry since the prior run. The software then identifies donor and recipient pairs that may be good matches for each other.

Based on the matches generated by the software, a living donor transplant chain is formed, consisting of numerous donors and recipients that are compatible, as determined by the registry. These donors and recipients are usually involved at different transplant centers, often across the country. Therefore, the matched donor and recipient may be on opposite sides of the country. In most cases, the matched donors and recipients are not asked to travel to another transplant center. Rather, the respective surgeries are performed at a transplant center close to the homes of the matched donor and recipient, and the donor's kidney is shipped to the recipient's transplant center. Kidneys are shipped via commercial airlines, similar to the process in which deceased donor kidneys are shipped.

KPD Programs in the U.S.

The largest KPD program is the National Kidney Registry (NKR), which was founded by the father of one of our young transplant candidates at NewYork-Presbyterian/91Â鶹¾«Æ·. Since 2008, we have performed over 200 kidney paired donation transplants by working with the National Kidney Registry. Visit  to view the current number of transplants that have been facilitated by the NKR.

An additional program is the , whose goal is to develop a national matching program. 

What are important factors in finding a match?

There are several factors that influence the length of time it will take to find a match within a Kidney Paired Donation registry.

For some transplant candidates, a match is found within a week or two of entering the registry, while for others, it may take a couple of years to find a good match.

It is important to remember that transplant candidates will also be on the deceased donor waiting list during this time, and a kidney could also become available via the deceased donor list. The factors that influence the length of time to find a suitable match are listed below.

Antibody Levels of the Transplant Candidate. Transplant candidates develop antibodies through prior exposure to human cells through blood transfusions, pregnancies or from previous transplanted organs. It often takes longer for sensitized recipients to find a compatible donor if the donor has genetic makeup (antigens) that the recipient has antibodies against.

Although these transplant candidates may find a match within a KPD program, it is possible that the candidate might have some antibody reactivity against the matched donor. In cases such as this, transplant candidates may need additional medications and treatments (called desensitization) designed to reduce antibody levels to a point where transplantation is possible. 

Blood Type. Similar to getting a blood transfusion, kidney transplantation requires that the donor and recipient have compatible blood types. The chart below shows which blood types are compatible.

Chart that details which blood types are compatible

Because 'O' donors are the universal donor and can donate to any blood type, there tend to be fewer 'O' donors available for 'O' recipients, who can only receive organs from type 'O' donors. This is an area where entry of compatible donor/recipient pairs into Kidney Paired Donation registries may be beneficial since this could free up some 'O' donors for 'O' recipients. To illustrate this, consider the scenario below.

A 40-year-old man is blood type 'AB', which means he can get a kidney from anyone. His wife is going to be his donor, and she has type 'O' blood. If this compatible pair enters a KPD registry, his wife's kidney could be donated to someone in desperate need of a transplant from someone with type 'O' blood, while the man can receive a kidney from a donor of any blood type, since a person with blood type 'AB' can receive an organ from a donor of any blood type.

Number of People in the Registry. The larger the pool of donors and recipients in the database, the greater the chance of identifying a match pair. In addition, the chance of finding matched pairs also has the potential to increase significantly when blood type and crossmatch compatible pairs are entered into KPD programs.

For these reasons, national exchange programs have the potential to generate the most transplant opportunities.

A match has been found – what happens next?

Once a potential match is found through a kidney paired donation registry, the crossmatch process is initiated between the matched donor and recipient.

 The crossmatch is a test where the donor and recipient blood are mixed together to see if the recipient's immune system has any reactivity against the donor. Reactivity signals that the recipient has antibodies against the donor, which are caused by previous exposure to human genetic material through blood transfusions, prior transplantation, and/or pregnancy.

 The presence of antibodies can increase the risk of acute rejection and graft loss after transplantation. However, this depends on the strength of the reaction.

In order to perform the crossmatch, the matched donor and recipient will each receive a kit in the mail containing blood tubes that need to be drawn and then shipped to a specified tissue typing laboratory.

 All donors and recipients involved will be notified within a few days of the res