Paired exchange programmes can expand the live kidney donor pool.

BACKGROUND Kidney paired donation (KPD) is an exchange of organs between two live donors, who are otherwise ABO incompatible or cross-match positive, and their intended recipients. The outcome is the generation of compatible transplants conferring an improvement in quality of life and longevity. METHODS Medline was searched for articles on KPD using a combination of keywords. Publications focusing on protocols and policy, mathematical modelling, ethical controversies, and legal and logistical barriers were identified. RESULTS Many are precluded from transplantation because of incompatibilities with their intended donors. KPD has the potential to increase the rate of transplantation by facilitating exchange transplants between otherwise incompatible donor-recipient couples. Ethical controversies surrounding paired donation include confidentiality, conditionality of donation, synchronicity of operations and the possibility of disadvantaging blood group O recipients. Logistical barriers hampering KPD programmes involve the location of donor surgery and organ transport. CONCLUSION Paired donation may expand the living donor pool by providing an alternative successful strategy for incompatible donor-recipient couples. Its widespread implementation will depend on resolving ethical and logistical constraints.