About
The Organ Procurement and Transplantation Network is working to develop a more equitable system of allocating deceased donor organs. The new approach, continuous distribution, will provide organ offers by considering many factors that contribute toward a successful transplant, at once.
This new framework will dissolve hard boundaries that currently exist in the classification-based system and be flexible enough to apply to all organ types. The donation and transplantation community is working together through research and analysis to design this framework to determine patient priority in the match run.
The current classification-based system gives points to candidates at various steps of a sequence. When attributes are reviewed in sequence, sometimes patients are placed on one side of a hard boundary that stops them from being prioritized further on the match run.
Continuous distribution will change organ allocation from placing patients into rank-ordered classifications for consideration, to considering all candidates at the same time. Candidates will be ranked with an overall score that is determined by considering multiple patient factors, “attributes”. This overall score includes not only medical urgency and patient outcomes, but also factors such as candidate biology and efficiency of organ transport.
Example of current classification-based system

The four candidates in this broad example, A, B, C and D, vary in terms of medical urgency, distance from the donor hospital, candidate biology (compatibility) and predicted one-year post-transplant survival.
In the current classification system, one of these factors could determine a particular order in which a candidate is prioritized in the match run.
For example, based solely on distance, candidate C would receive an offer first, followed by A, B and D. If priority is given to medical urgency, candidate B would receive the first offer, followed by A, D and C.
Continuous distribution is intended to weight all factors together to determine offer order. Depending on the formula chosen, candidate B may be the first to receive an offer based on a combination of high medical urgency, medium survival probability and moderate distance from the donor location. Depending on the weighting of factors, the remaining order may be A, C and D. Candidate C, with the shortest distance from the donor hospital, might appear ahead of Candidate D, who has medium medical urgency but is the farthest from the donor location.
Goals of the new continuous distribution framework are consistent with allocation requirements in the OPTN Final Rule:
- Prioritize sickest candidates first to reduce waitlist deaths
- Improve long-term survival after transplant
- Increase transplant opportunities for patients who are medically harder to match
- Increase transplant opportunities for candidates with distinct characteristics like candidates under the age of 18 or prior living donors
- Consider resource requirements for procuring and transporting organs
The new points system
Attributes related to the overall score include medical urgency, expected post-transplant outcome, candidate biology, patient access and efficiency of organ placement.


A higher score puts a patient closer to the top of the waitlist and more likely to receive an organ transplant.
Attributes and the goals they support


Medical Urgency: Amount of risk to a candidate’s life or long term health without receiving an organ transplant.
Post-Transplant Survival: A candidate’s likelihood of survival for one year after receiving a transplant.
Candidate Biology: Medical characteristics of a candidate can make them harder to match. This can include a candidate’s blood type, their body’s sensitivity to accepting an organ, or their height.
Patient Access: This addresses transplant access for candidates under the age of 18, as well as prior living donors, those who have previously donated an organ or part of an organ.
Placement Efficiency: The amount of resources required to identify a suitable candidate willing to accept the organ and deliver the organ for transplant.

In this match run example, each color represents a different attribute and the length of the bar indicates the amount of points given to that attribute. Candidates receive points from multiple attributes and can move up or down depending upon each attribute. Candidate A received the most points in this match run example.
Each attribute will have a specific weight, meaning some attributes will have more effect than others on the total score, yet no one attribute will decide an organ match. The total score will determine a candidate’s position on the waitlist.
In today’s allocation system, some attributes define allocation classifications. Meaning, if candidates have one of those defining attributes, they receive absolute priority over otherwise similarly situated candidates. To inform the decisions about an attribute’s weight, the community is invited to participate in an exercise using a method called the Analytic Hierarchy Process, or AHP.
Developing the framework
Many decisions have to be made, involving multiple stakeholders and comprehensive research, to develop the new system and achieve improvements for the entire donation and transplantation community. Each organ specific committee will move through the steps below to develop a policy proposal that will open for public comment and be submitted to the Board for final approval.
Community input is being used through each phase of development to inform evidence-based rules for the new system.


- Identify attributes
Each of the above attributes will be considered uniquely with regard to each candidate, who will receive points that are calculated into an overall score. - Assign values
- Prioritize attributes against each other
The specific weight of each attribute determines how much influence each attribute will have toward the overall score. This step has two parts:- Review and analyze results of the AHP exercise from OPTN committees and the broader community
- Convert attributes into points
For each attribute that will be considered toward the overall score, a decision will be made about how to assign points to candidates according to differences in the attribute. For example, how many points do we give to blood type A versus O? 100 miles versus 1,000 miles?
- Prioritize attributes against each other
- Build framework
- Develop the composite score
The composite score will be a combination of decided weights and rating scales. - Conduct sensitivity analysis
A sensitivity analysis is an analysis used by statisticians to change a single variable slightly in order to measure the impact on an outcome. For continuous distribution, a sensitivity tool has been built to evaluate continuous distribution of lungs. For example, if a change is made to the weight of any attribute, the new match run will be shown as the outcome.
- Develop the composite score
- Modeling and analysis
- Scientific Research and Transplant Registry (SRTR) modeling and results
The SRTR will take proposed allocation policies and model them to determine the impact on candidates. These results will be produced in a report to help identify any potential unintended consequences or harmful outcomes for these example groups. These results will estimate the benefit of the new proposal and inform any needed improvements.
- Scientific Research and Transplant Registry (SRTR) modeling and results
- Public comment on policy proposal
Considering community input, modeling and analysis, and committee project work, propose a new composite score as a policy proposal for public comment. See details around the policy development process, including public comment, here. - Board approval
After the Board of Directors approves the proposal with the new framework, plans for implementation begin. - Implementation
Implementation of the policy for lung allocation is projected to take approximately 12 months due to the range of changes, required education to the community, and expected impact.
Progress by organ
The adopted framework will be flexible enough to apply to all organ types. Using the same framework for all organs will improve organ allocation by creating consistency and transparency for the entire transplant community.
The current organ matching process is different for each organ type. To develop a framework that works for each organ, each organ type will be looked at individually, starting with lung.
Organ | Expected start |
---|---|
Lung | January 2019 |
Kidney | June 2020 |
Pancreas | June 2020 |
Liver | January 2021 |
Intestine | January 2021 |
Heart | January 2023 |
Vascularized Composite Allograft | January 2023 |
Take action
A method called the Analytic Hierarchy Process (AHP) is being used to inform the development of the framework through a prioritization exercise. AHP asks participants to compare two attributes against each other and select their level of importance when considering a candidate for organ transplant. This information will be used to inform the weight of each attribute to the overall score.
This method was chosen because it has been used effectively by other health care groups to involve patients in making clinical decisions.
Participate in the exercise
Your input is critical to the process and will support the development of a framework that is best for the donation and transplantation community.
The AHP will be used to inform each organ committee as they move through the process of developing the framework for each organ type separately.
The opportunity to participate in the AHP exercise for lung closed Oct. 1, 2020.
Check back here for open opportunities to participate.
Video about the AHP prioritization exercise
We encourage all members of the donation and transplantation community to participate in this important exercise.
Background & resources
In December 2018, the OPTN approved a continuous distribution model as a framework for developing future organ allocation policy, upon the recommendation of a specially called Ad Hoc Geography Committee. Continuous distribution was selected after consideration of multiple alternative frameworks and was developed with input from the public and the transplant community. Recent changes to organ allocation have been made in an effort to align with this new framework and improved equity in organ allocation.
- 2019 lung concept paper (PDF 1.2 M; 8/2019)
- Video about the AHP prioritization exercise
- Guidance on effective practices in broader distribution (PDF - 727 K; 6/2019)
- Proposed distribution frameworks overview (PDF - 1.3 M; 8/2018)
- Ad Hoc Geography Committee's charge, its members, and summaries of previous meetings.
- Data Request from the OPTN Kidney Transplantation Committee
Provide simulation data on effect of removing DSA and region from kidney/pancreas/kidney-pancreas organ allocation policy- View kidney pancreas analysis (PDF; 12/2018)
- Access kidney pancreas results (XLSX; 12/2018)
- Article in the Journal of Health & Biomedical Law analyzing legal issues related to the emergent lung allocation policy enacted in November 2017. (PDF - 180 K; 7/2018)
- June 6 memo to members from Board President Yolanda Becker, M.D. (PDF - 51 K; 6/2018)
- June 20 update to members from Board President Yolanda Becker, M.D. (PDF - 63 K; 6/2018)
- Read an August 13 reply from the OPTN to HRSA’s memo of July 31. (PDF - 251 K; 8/2018)
Alexandra Glazier, J.D., M.P.H., President and CEO of New England Donor Services and a member of the Ad Hoc Geography Committee, describes the legal and regulatory history and perspective for organ distribution in the United States, as well as recent legal developments that may influence how current and future organ distribution policy is interpreted.