This article was reviewed and updated in October 2025 to maintain the latest statistics.
Transplants often mean the difference between life and death for people with renal failure, but kidneys are not readily available to all who need one. The donor shortage frequently leaves people waiting—trapped on dialysis for extended periods with no end in sight.
The wait time is nearly five years on average for a deceased-donor kidney via the national registry. Because people can live with just one of their two kidneys, transplants from living donors are also an option. Living-donor transplantation has saved countless lives, but it has traditionally required finding a compatible donor among a person’s close friends and family—which isn’t always possible.
As of 2025, more than 103,000 people are waiting for life-saving organ transplants in the United States, and nearly 90,000 of them need a kidney. The Health Resources and Services Administration reports that approximately 5,000 new people are added to the list every month, while 13 people die each day waiting for a kidney transplant.
The disparity between supply and demand is at a crisis point, but experts are developing innovative ways to expand the donor pool.
The Birth of the Kidney Swap
Living donor transplants require the donor and recipient to have compatible blood and antibodies. If a friend or relative wants to donate but isn’t compatible, what can be done?
That’s where kidney swaps come in. A kidney swap facilitates odd pairs to find matches with individuals outside their orbit. Kidneys from perfectly matched donors can function for more than 30 years.
A swap can go something like this: your brother needs a kidney, and you want to donate but your blood type isn’t a match, or you have particular antibodies that may cause rejection. The solution? You give your kidney to a stranger who is a match, and their friend or relative donates a kidney that is compatible with your brother. It’s a game of matchmaking that would make Yente proud.
In 2004, Lloyd Ratner, MD, Director of the Kidney and Pancreas Transplant Program at Columbia, became the first surgeon in New York state to perform a two-way kidney swap, involving four people (two donors, two recipients). Since then, even larger swaps have been performed, including a "mega-chain" in 2007 that linked 60 people, 30 kidneys, and 17 medical centers from all around the country.
These paired-exchange programs have created matches for people who might never have found a kidney otherwise and saved thousands of lives. But there are some drawbacks to such a sprawling transplant network: time, distance, cost, and the many unpredictable factors in between.
The Smaller the Kidney Swap the Better
“The goal of these big chains is to help the most complex patients,” says Dr. Ratner. “But bigger isn’t always better. It’s really preferable to do swaps with fewer patients and do them more often.”
The first barrier to the mega-swap is logistics. “Say we want to swap a kidney with a patient at a hospital in Indiana or Ohio,” says Dr. Ratner. “Our operating day is Tuesday, and theirs is Thursday. This is a problem since swaps must be done simultaneously.”
Next comes the issue of organ viability. The longer a kidney remains outside the body, the less likely it is to function well initially. Fast, reliable transport is key.
“It’s much easier to do a swap between New York and Los Angeles since there are direct flights several times a day,” says Dr. Ratner, “It’s far more challenging to arrange one with a patient in a small town in rural Pennsylvania. You have a better chance if you can get to a major city."
Another impediment is financing. It’s essential to work within the complexities of healthcare coverage to secure swaps as efficiently as possible. Insurance companies have agreements with certain hospitals, while others are out of network. In New York, Medicaid typically does not cover non-emergency medical procedures performed out of state without special approval, which can limit access for transplant candidates seeking out-of-state centers.
Figuring out who will pay for the surgery, and where, is inherently tricky for most Americans. Smaller swaps, Dr. Ratner says, can alleviate some of these burdens.
Beyond the Swap: Finding A Diamond in the Rough
Swaps are far from the only option. With a passion for the art of matching and pragmatic approach to kidney acquisition, wait times for donor organs can be much shorter—as Dr. Ratner has demonstrated at Columbia, where average wait times have been cut by more than half.
“It’s because we’re good at finding the right match,” says Dr. Ratner. Most hospitals take only the strongest and most durable deceased-donor kidneys for transplantation. “Four out of five donor kidneys we use have been turned down by other institutions,” he adds.
These aren’t bad kidneys. Some may not be perfect on paper, but matching requires a personalized approach—finding a great fit for the individual.
“Getting a kidney is like getting a used car. Some have more miles, and some are easier to maintain, others just need a small repair then are good for years,” adds Dr. Ratner. “We can fix kidneys that have problems with blood vessels, and in many cases, we can make do with organs that are less than perfect.”
Age and lifestyle factor significantly when matching a kidney. “Think of a Chevy with 100,000 miles,” says Dr. Ratner. “You may not want to drive it coast to coast each month, but it’s great if you want to get to the grocery store.”
Someone who is elderly or petite may do well with a kidney that has some extra wear. “That patient may have a fifty percent chance of dying over five years without a transplant,” adds Dr. Ratner. “If this organ lets them live another decade, that’s a big survival gain.”
The mission is to move people off the transplant list and back to leading healthy, productive lives. And today, more people than ever have access to a kidney transplant. Here are the most important things to know:
- Small swaps are best. It’s safest to go to a kidney transplant center with a large pool of local donors, allowing them to limit their swaps to no more than two or three matched pairs at a time.
- Living donor transplantation is less invasive than ever. With new minimally invasive techniques, living donors now heal faster, with less post-op pain, and better cosmetic results. Their time in the hospital has been cut down to two days. Hospitals that encourage living donors can choose from healthier organs.
- There are new treatments for incompatible donors. If a perfect match isn’t available, it is possible to match incompatible donors. Special techniques allow doctors to filter the blood and remove antibodies that might cause rejection. This approach is called plasmapheresis and can be combined with IV immunoglobulin. It’s available at major transplant centers.
- Less-than-perfect kidneys can be repaired for transplant. A kidney does not have to be 100% to dramatically improve the quality of life for a person with kidney failure. Skilled surgeons can fix certain defects. It’s now possible to use two suboptimal kidneys to perform the function of a single “perfect” kidney transplant. This approach often works well in patients 65 and older, giving them a reprieve from dialysis and many added years of life.
“You can always find something wrong with a deceased donor kidney, but we try very hard to find something right,” says Dr. Ratner. “This approach is saving lives.”
Interested in becoming a living donor? You can register online today.