Inside the System: How Does Organ Allocation Work?
Education & Research With over 123,000 people in the U.S. awaiting a life-giving transplant, it’s never been more crucial to be equitable with the organs made available.
The United Network for Organ Sharing (UNOS) runs the national transplant system under contract with the federal government. The entire allocation system is governed by national policy created by a community of transplant professionals and patient representatives.
Objective medical criteria determine how quickly you receive a transplant—the amount of money you make, the color of your skin or whether you have won three consecutive Super Bowls does not.
The national allocation system cannot and does not consider non-medical factors.
Inside the system
Before an organ is allocated, UNOS’ computer system automatically screens out transplant candidates on the waiting list who are incompatible with the donor based on blood type, height, weight and other medical characteristics. Then, the remaining candidates are ranked based on allocation policy.
"Complex mathematical algorithms that consider medical characteristics of the transplant candidate help determine which individual is likely to die without a timely transplant."
While many factors used to match organs with patients in need are the same despite the organ in question, the system must still accommodate some unique differences for each organ. Complex mathematical algorithms that consider medical characteristics of the transplant candidate help determine which individual is likely to die without a timely transplant.
Heart and liver allocation is based on the candidate’s medical urgency. A combination of medical urgency and post-transplant survival applies to individuals waiting for lungs. Kidneys are allocated primarily based on time spent on the waiting list or on dialysis.
There are 58 local donor service areas and 11 UNOS regions in the United States that are used in allocating organs. Hearts and lungs have less time to be transplanted, so a radius from the donor hospital is used instead.
Proper organ size is critical to a successful transplant, which means children often respond better to child-sized organs. Although pediatric candidates have their own unique scoring system, children essentially are first in line for other children’s organs.