How Does a Kidney Transplant Chain Work?

Nondirected Kidney Chain

A Non-Directed Kidney Transplant Chain helps the most people get Kidney Transplants.

There are 2 types of Kidney Transplant Chains: Closed and Non-directed. 

Closed Kidney Transplant Chain

Kidney Paired Exchange (aka Kidney Swap or Kidney Domino) is involved in the closed kidney chain.

In a Closed Chain, there are many kidney pairs. A “kidney pair” includes a kidney donor and the person they want to donate to, a recipient. Most often, this is a family member or close friend. Unfortunately, they are not compatible (their blood and tissue typing are not good matches). In the diagram, this is Recipient 1 and Donor 1.

There are many other pairs like them. Recipient 2 and Donor 2, Recipient 3 and Donor 3, etc. are other “kidney pairs” that don’t match each other. The number of pairs can vary. 

 Closed Kidney Donor Chain

 These donors are willing to give their kidney to someone else so that their loved one can receive a kidney.  All these pairs go into a computer system to see who can be matched. In this example, Donor 1 is matched with Recipient 2. Donor 2 is matched with Recipient 3. And Donor 3 is matched with Recipient 1. This allows each person who needs a kidney to receive one, even though they do not know their donor.

Non-Directed Kidney Transplant Chain

Two types of living donations are needed for this type of kidney transplant chain to take place. This has also been called a daisy chain and nonsimultaneous, extended, altruistic donor chain (NEAD).

1. Kidney Paired Exchange has already been discussed above. In this situation, the same people are matched to donate and receive kidneys with one difference. Recipient 1 is not matched with someone from the chain. Donor 1 will not give their kidney away until Recipient 1 has a kidney.

Nondirected Kidney Chain

2. This brings us to the second type of living donation, Non-Directed (aka Altruistic or Good Samaritan). This is a kidney donor who is willing to give their kidney to a stranger or anyone who needs a kidney. In this example, this Non-Directed Donor goes into the computer program and is matched with Recipient 1. Now Donor 1 is willing to donate to Recipient 2 and the chain is started. It takes a non-directed living donor to start this chain.

The more living kidney donors that are available, the more people can get kidney transplants. With 90,000 people on the kidney transplant waiting list, we need more living kidney donors to help those on the list.

Organizing a chain is complex.

The living donor and recipient transplant coordinators at the transplant center work closely together with the transplant and surgery teams. Sometimes this involves many transplant centers throughout the country and can take place over months or years.

The average number of people getting a kidney through a chain is 4.8.

According to the Guinness World Record, the longest kidney transplant chain in the world was done through National Kidney Registry and involved 25 transplant centers, 70 surgeries, 35 kidney donors, and 35 people who received kidney transplants. This chain was started by Kathy Hart, a non-directed kidney donor at the University of Minnesota Medical Center on January 6, 2015. This amazing behind-the-scenes story can be found HERE.

In 2017, The University of Alabama at Birmingham reported the nation’s longest kidney chain with 114 people. Tyler Williamson was the non-directed kidney donor that started the chain. This remarkable story can be found HERE

These chains are important, whether the chain involves 4 people or 114 people. Hopefully, you can see and understand the importance of non-directed kidney donors and their benefit to kidney chains. 

Consider This!

A single Non-Directed Kidney Donor giving the gift of life to one stranger has helped the most number of people on the transplant waiting list by starting the largest Kidney Chains!


Rees, M., Kopke, J., Pelletier, R., Segev, D., Rutter, M., Fabrega, A., Rogers, J., Pankewycz, O., Hiller, J., Roth, A., Sandholm, T., Univer, T., & Montgomery, R. (2009). A Nonsimultaneous, Extended, Altruistic-Donor Chain. The New England Journal of Medicine, 360(11), 1096–1101.


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Glenna Frey, APRN-CNS, is a nephrology nurse who donated her kidney in April 2017 to a stranger.
Amanda Frey, M.A., LMFT, LPC, is a Marriage & Family Therapist living with kidney disease.
Together, they co-founded Kidney Donor Conversations in 2018 to provide education about Living Kidney Donation.