Some American patients get priority on organ donor lists by signing up on several lists, creating a system in which the wealthy have a better chance of getting a transplant. Critics complain that the practice, known as "multiple listing", is unfair to the poor, and expensive for Medicare, which normally pays most of the costs. People donate organs with the idea that everyone will have a fair shot at getting them," says bioethicist Arthur Caplan. "I think it diminishes people's willingness, especially the poor, to become donors."

For the purpose of organ transplants, the United States is divided into 11 regions. Organs normally stay within a region and go to patients depending on how sick they are and how long they have been waiting. But patients can better their luck by signing up on two or more lists. The poor can hardly afford this, as it involves extra air fares. Duplicating expensive blood tests and medical checkups also costs the government dearly. About 6,000 of the 90,000 Americans waiting for an organ are listed in two or more regions, according to the United Network for Organ Sharing. UNOS has tried to ban the practice several times, but lost after opposition from patient advocacy groups and large transplant centres.