Last year, only 13,000 of them got kidneys. Another 3,000 died on the waiting list.

Only half of potential organ donors actually donate, but even if every potential donor came through, many on the waiting list still wouldn't be helped.

Mark Schnitzler

Although the vast majority of donated organs come from people who have died, transplanting kidneys from living donors has gained popularity in the last decade. These donations — many times made by family members — also have the greatest chance of being successful and can happen quickly, often in less than a year.

But what if society chose to pay living, unrelated donors for their kidneys? Setting all ethical issues aside — how much would one of your kidneys be worth?

Mark Schnitzler, Ph.D., assistant professor of health administration in the School of Medicine, and colleague Arthur Matas, M.D., professor of surgery at the University of Minnesota, set up a mathematical model to determine whether it would be economically feasible to pay donors.

Their study shows that society could pay each donor $90,000 and easily break even.

"It's a large number," Schnitzler said. "Society saves money, and the patient receives both quality of life and life-extension benefits from the donor."

For their analysis, the researchers assumed the establishment of a government-regulated system in which a fixed price would be paid to the donor and the kidneys would be allocated by a pre-defined system. Factors included in the calculations were patient survival, cost of dialysis, organ survival after transplantation, cost of transplant surgery, maintenance costs and the cost of returning to dialysis.

For the recipient of a living, unrelated donor kidney transplant, the estimated medical expense for 20 years following transplant is $277,600. The expected medical cost for a dialysis patient for that long is $372,179.

The difference of $94,579 is the expected savings that would be generated by a living, unrelated donor — a savings that could be paid to the donor without increasing costs.

However, Schnitzler and Matas said there are additional benefits.

"We should also value the extra life — the quality of life — that patients get following transplantation," Schnitzler said.

"If you compare that to what we already are willing to pay for dialysis, it increases the value of the donated kidney even more."

The recipient of a living, unrelated donor's kidney can expect, on average, nearly nine extra years of life after transplant. If that patient had remained on dialysis for life, he or she could only expect 5.4 years.

Schnitzler said assuming society values the gained life at the same rate it's willing to pay for dialysis, the cost-effectiveness benefit increases by nearly $175,000.

He admits that potentially paying donors generates strong ethical debates.

Some argue that living donations shouldn't be done in the first place because the donor has to endure a major operation that can result in serious complications and even death. But donors are heavily screened prior to surgery and have to be extremely healthy people.

Schnitzler said death from procedure complications is so rare it's hard to estimate the risk.

"There really is very little physical harm done to the donor, and there is great benefit to the recipient," he said.

"In balance, the benefit far outweighs the harm in donation."

He has stronger concerns about the potential exploitation of donors.

"Who is going to be more likely to walk up and say, 'I'll be a donor for $90,000'?," he said. "Clearly, a poorer person is more likely to be induced to donate than a millionaire."

He also noted that if society decided to pay living kidney donors, it may become necessary to pay all donors — living and deceased — and to pay for other organs as well.

"Does that change how much you can pay? Absolutely," he said. "It only changes the break-even point, though. It doesn't change the benefit."

Schnitzler said he personally hasn't made up his own mind about whether society should be paying for living kidney donors or whether there should even be living donors.

But he is sure that every day, people are dying while waiting for organs.

"Altruistic organ donors are true heroes, and nothing should diminish the quality of their wonderful acts," he said. "But for over 40 years, numerous attempts have been made to increase altruistic organ donation. We don't have enough, and we need to find a way to have more."