Skip to main content

Lung continuous distribution policy

Toolkit sectionsToolkit


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, anticipated to take effect early in 2023, creates 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.

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, rare blood type, 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

Post-implementation monitoring

OPTN member evaluation preview

FAQs & resources

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

  • LUN102 Basic Principles of Lung Continuous Distribution
  • LUN103 Unacceptable Antigens & CPRA in Lung Continuous Distribution
  • LUN104 Scoring and Exceptions Under Lung Continuous Distribution
  • LUN105 Preparing for Implementation of Lung Continuous Distribution
  • SYS183 Using the Lung CAS Report
  • SYS186 UNetSM for Lung 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

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)

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)

Member webinar

A webinar was held on Oct. 13, at to help lung transplant programs prepare for implementation of the lung allocation policy based on continuous distribution. The presentation reviewed the lung composite allocation score (CAS) and how it differs from the current lung allocation score (LAS).

View slides