Preemptive kidney transplantation: an ethical challenge for organ allocation policies.

Preemptive transplants are advisable in advanced stages of kidney disease. The clinical advantages of preemptive transplantation over dialysis are evident. Nevertheless, preemptive transplantations raise ethical concerns, particularly regarding the allocation of medical resources. The present article proposes some criteria for organ allocation policies regarding preemptive transplantations: criteria regarding medical benefit and justice are absolutely essential when addressing the issue of organ allocation, but other ethical values should also be taken into account. The "principle of double effect" offers useful pointers.