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Submit exception requests for the lung CAS transition starting Feb. 9

Submit exception requests for the lung CAS transition starting Feb. 9

Updated March 2, 2023: The lung allocation system based on continuous distribution was originally scheduled to take effect on March 2, 2023. The lung continuous distribution policy is now expected to implement on March 9, 2023. This system notice has been updated to reflect the change in expected implementation date.


  • All lung transplant programs

Early exception request submission date

  • Starting Feb. 9, 2023


When continuous distribution of lungs is implemented, which is expected on March 9, 2023, the Lung Allocation Score (LAS) will be replaced by the lung Composite Allocation Score (CAS). As a result, currently held LAS exceptions will be eliminated on March 9. Prior to implementation, transplant programs may submit lung CAS exception requests by goal type so that approved exceptions will be in place when continuous distribution of lungs is implemented.

What you need to do

Utilize the Lung CAS Report in the Data Services Portal and the national data found in the Lung CAS summary data on to review your lung and heart-lung candidates to determine if they will need a CAS exception request under the new system.

To request a goal-based exception for lung or heart-lung candidates before implementation, transplant programs must use the Lung CAS Exception Request Form found in UNetSM Resources, under Forms/Tools (education is available on this process in UNOS Connect and is referenced below). Return the completed form starting Feb. 9, 2023 via secure email to [email protected].

Transplant programs are encouraged to submit forms by Feb. 23, 2023 to ensure the Lung Review Board has sufficient time to adjudicate cases prior to implementation of lung continuous distribution.

Starting on March 9, 2023, new exception requests should be submitted in WaitlistSM.

Additional details

The completed form will be sent to the Lung Review Board (LRB) for review. Approved goal-based lung CAS exceptions will be effective upon implementation of lung continuous distribution. Approved exceptions are valid until the candidate is transplanted, removed from the lung waiting list, or the program withdraws the exception.

Education and resources

  • On
    • Lung CAS summary data
      • Utilize this summary data when evaluating your lung and heart-lung candidates for CAS exceptions
  • In the Data Services Portal
    •  Lung CAS Reports
      • Utilize this report to examine your candidates’ scores when evaluating them for CAS exceptions (education available in UNOS Connect referenced below)
  • In UNOS Connect
    •  SYS183: Using the Lung CAS Report in Data Portal
      • Learn how to use the Lung CAS Report to examine your candidate scores (15 min)
    • LUN104: Scoring and Exceptions Under Lung Continuous Distribution
      • Review CAS examples to determine if submitting an exception request is appropriate (30 min)
    • SYS186: UNet for Lung Continuous Distribution
      • Learn the process of submitting an exception in UNet (30 min)
  • A lung CAS calculator will available on the OPTN website starting Feb. 2, 2023
  • Upcoming webinars:
    • Feb 10: Lung continuous distribution: Exception requests and Review Board
    • Feb. 17: Lung continuous distribution and multi-organ allocation
    • Feb: 23: Patient webinar-Preparing for lung continuous distribution


If you have questions relating to implementation, contact UNOS Customer Service at [email protected], or call 800-978-4334 from 8 a.m. to 7 p.m. ET.

For policy-related questions, contact [email protected]

For submission-related questions, contact [email protected]

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