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Lung transplants for blood type O increase after modified blood type rating scale

Published on: Monday, March 11, 2024

A new data monitoring report evaluates key metrics three months after the implementation of a policy that modified how blood type is incorporated into lung allocation under the current continuous distribution (CD) framework. Since implementation, there has been a 11.6 percent increase in lung-alone transplants for candidates with blood type O. 

Additional key points based on the first three months of the modified blood type rating scale:

  • The waiting list mortality rate remained similar or decreased for candidates of all blood types
  • The median time to transplant remained similar or decreased for candidates of all blood types
  • Median distance from the donor hospital to transplant program increased to 417 nautical miles (compared to a median travel distance of 193 nautical miles in the Pre-CD era1
  • and 379 miles in the Post-CD era)

These early findings were presented to the OPTN Lung Transplantation Committee on Feb. 8, 2023. The Committee will continue to monitor this policy to understand whether the changes are meeting the intended goals. The one-year monitoring report for continuous distribution of lungs will be released this spring and subsequent monitoring reports will be published on the OPTN website annually for three years as outlined in the briefing paper.


Lung is the first organ type to adopt the flexible and patient-centric system known as continuous distribution that went into effect March 9, 2023. It was determined in July 2023 that the modeling results used to inform development of the continuous distribution policy did not incorporate screening for incompatible blood types in the simulation, resulting in lower than expected transplant volume for blood type O recipients. Incompatible blood type screening was programmed correctly in the allocation system. The OPTN Board of Directors approved a policy update on Sept. 22, 2023, to improve access to transplant for blood type O candidates, and the policy change was implemented on Sept. 27, 2023. For more information, refer to the policy notice.


1 This report compares 3 policy eras defined as below:

  • Pre-CD era: Three months before the initial implementation of CD, Dec. 08, 2022 -March 08, 2023
  • Post-CD era: Three months with the original blood type rating scale, June 28, 2023 -Sept. 26, 2023
  • Post-CD + ABO Mod- First three months with the modified blood type rating scale, Sept. 27, 2023 -Dec. 26, 2023