Last year, 43% of kidneys transplanted in the U.S. came from living donors, up from 28% a decade ago.
But a biological barrier often blocks a transplant from a relative. In about a third of all would-be pairs, blood types are incompatible. In others, the sick person has antibodies that can initiate a rejection of the donated organ. It’s heartbreaking “to have the treasure of the live donor and then have that not go forward because of a biological obstacle,” says Massachusetts General Hospital transplant surgeon Francis DelMonico.
Occasionally, transplant centers spot a way out: One New England father with blood type A couldn’t donate a kidney to his daughter with blood type B. So he gave a kidney to a teenager with blood type A, and the teenager’s sister gave a kidney for the man’s daughter.
Such swaps, however, typically occur only when happenstance alerts surgeons to the possibility. Economist Alvin Roth and co-authors have devised an algorithm, however, that computes all the possible swaps and which is incentive-compatible.
…when Dr. Saidman gave the economists details on 45 pairs in which the would-be donor was unable to give a kidney to the intended recipient. Even though each of the 45 had a donor willing to spare a kidney, all were stuck waiting for the right person to die. With swaps involving two kidneys, the economists found, eight transplants were possible. If swaps involving three kidneys were possible, then 11 transplants were possible.
Addendum: Alert readers will note that kidney swaps are quite similar to organ clubs an idea for saving lives that has been implemented by Lifesharers.