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Lung continuous distribution policy

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In December 2021, the OPTN Board of Directors approved a policy to fundamentally change the process for matching lung donors and recipients. The new policy took effect on March 9, 2023, creating a single, composite allocation score, specific to each match from a lung donor. It will replace a series of matching categories historically used to assess patients’ transplant priority.

The new policy is based on a concept known as continuous distribution. Each lung transplant candidate will receive a composite allocation score for each organ offer. This score combines weighted priority for a number of attributes that reflect the candidate’s need for a transplant and how well the candidate matches the organ donor.

On Sept. 27, 2023, additional changes took effect related to how the OPTN lung policy accounts for blood type. Read the policy notice for more details.

Find more information on lung continuous distribution.


Summary of policy changes

  • The new policy will produce a Composite Allocation Score (CAS). This score has point values that represent each of the attributes used to match organ offers with transplant candidates. The people who have the highest number of points for that donor will be the first to get organ offers. Points are awarded based on the following attributes:
    • How urgently the candidate needs a transplant
    • How likely the person is to do well once transplanted
    • Whether the patient has any biological issues that would make him or her harder to match with a donor (for example, blood type incompatible with many donors, immune system sensitization and/or being much taller or shorter than most donors)
    • Whether the candidate is younger than age 18
    • Whether the person has been a prior living organ donor
    • How efficient it is to transport the lung(s) from donor hospital to transplant hospital (for example, ease of scheduling ground transport or flights)
    • The distance between donor hospital and transplant hospital
  • The CAS will extend to decimal point values, meaning there should not be many instances where two or more candidates will have the exact same score. But if they do have a tie score for a given donor offer, the person who has waited longer for a transplant would receive an organ offer before any others who have not waited as long.

Policy documents

Establish continuous distribution of lungs

Modify lung allocation by blood type

Post-implementation monitoring

OPTN evaluation plan

Six-month monitoring report

Three-month monitoring report: Early lung monitoring report shows increase in transplants following implementation of lung continuous distribution

FAQs & resources

The following professional education modules on this policy change are available on the OPTN learning management system:

Overview courses for all members:

  • Unacceptable Antigens and CPRA in Lung Continuous Distribution 
  • Lung Continuous Distribution Scoring and Exceptions 

For transplant programs:

  • UNetSM for Lung Continuous Distribution

For OPOs:

  • OPO Considerations for Lung Continuous Distribution 

For Review Board members:

  • Lung Review Board Member Orientation under Continuous Distribution

Frequently Asked Questions: Continuous Distribution of Lungs

Information about the new policy, with an emphasis on what lung transplant programs need to know.
Frequently Asked Questions: Continuous Distribution of Lungs

Crosswalk of Covariates used for the Post-Transplant Survival Calculation in Lung Allocation

Transplant hospitals can use this crosswalk to compare the covariates for the one-year post-transplant calculation used in the LAS prior to March 9, 2023, with the covariates for the five-year post-transplant calculation effective March 9, 2023.
View crosswalk

A Guide to Calculating the Lung Composite Allocation Score (Lung CAS)

Detailed information about the attributes included in the lung CAS, the statistical weighting of each factor, and the algorithm for calculating the score.

A Guide to Calculating the Lung Composite Allocation Score (Lung CAS) (last updated, 11/15/2023)

Patient FAQs: Lung allocation based on the Composite Allocation Score (CAS)

Information for lung transplant candidates and caregivers about the new lung allocation system and how it differs from the current policy.
Patient FAQs: Lung allocation based on the Composite Allocation Score (CAS)

Lung CAS animated explainer video

Learn how the lung Composite Allocation Score (CAS) is calculated and used in lung allocation in this brief animated video. Watch video.

Patient questions and resources for new lung allocation policy handout

Patient handout with answers to frequently asked questions, questions to ask your transplant coordinator, and resources for further learning.
View patient handout