Kidney paired donation chains are fragmented across competing registries, so patients enrolled in one registry miss matches that exist in another and 30-63% more transplants could happen

When a patient needs a kidney and has a willing living donor who is incompatible (wrong blood type or antibody mismatch), they can enter a kidney paired donation (KPD) program: their donor gives a kidney to a stranger whose donor is compatible with the original patient, creating a chain of swaps. In theory, KPD could dramatically increase living donor transplants. In practice, the U.S. kidney exchange market is fragmented across multiple competing registries — the OPTN/UNOS national program, the National Kidney Registry, the Alliance for Paired Kidney Donation, and individual hospital programs — that do not share patient pools. So what? A patient enrolled in one registry can only be matched against other patients in that same registry. If the perfect match exists in a different registry, neither patient knows, and neither gets transplanted. Research in operations science has shown that this fragmentation causes 30% to 63% fewer transplants than would occur with a unified national matching pool. Some patients enroll in multiple registries simultaneously, which creates a different problem: when one registry builds a chain involving that patient and the patient has already been matched elsewhere, the entire chain collapses, wasting weeks of coordination work and delaying transplants for everyone involved. So what? Each failed match means the patient stays on dialysis. Dialysis patients have a five-year survival rate of roughly 35%, compared to 85% for transplant recipients. Each month on dialysis costs Medicare approximately $7,500 per patient. The fragmented KPD system is not just an inefficiency — it is a body count. Patients are dying because registries compete instead of cooperate, and there is no regulatory mandate to unify the matching pools. This problem persists because each KPD registry is a separate organization with its own funding model, intellectual property in its matching algorithms, and institutional incentive to keep patients in its own pool. Registries compete for transplant center partnerships, and a center's choice of registry becomes a business relationship, not a medical one. There is no federal requirement to participate in a unified exchange, and OPTN's own KPD program is underfunded and underutilized relative to the private registries.