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Modify Heart Policy for Intended Incompatible Blood Type (ABOi) Offers to Pediatric Candidates

eye iconAt a glance

Current policy

Currently, pediatric heart candidates who are registered on the waiting list as Status 1a or 1b before they turn two years old have the option to accept hearts from donors whose blood type is incompatible with their own. If they are less than one year old at the time of the match run, they are classified as a primary blood type match per OPTN policy. If they are at least one year old at the time of the match run, they can be a secondary blood type match if they meet certain isohemagglutinin titer values and haven’t received treatments that could lower their titer values. Pediatric lung candidates also have similar requirements.

Supporting media


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Proposed changes

  • Allow all pediatric heart, heart-lung, and/or lung candidates registered before turning age 18 the option to accept an ABO-incompatible heart, heart-lung, and/or lung
    • Will now include pediatric heart Status 2 candidates and pediatric priority 2 lung candidates
    • Will change eligibility from candidates registered before turning two to candidates registered before turning 18

Anticipated impact

  • What it's expected to do
    • Allow more flexibility for transplant programs when caring for pediatric heart, heart-lung, and/or lung candidates
    • Increase access to heart and lung offers for pediatric candidates who are able to accept an ABO-incompatible organ
    • Improve waitlist mortality among pediatric heart candidates
  • What it won't do
    • Require pediatric heart or lung patients to accept an ABO-incompatible organ
    • Change the existing heart ABO-incompatible policy requirements regarding isohemagglutinin titers or treatments that could reduce titers
    • Change policy for ABO-compatible heart, lung, or heart-lung transplants

Terms to know

  • ABO-incompatible: When people who have one blood type receive blood from someone with a different blood type, this may cause their immune system to react.
  • Isohemagglutinin: The naturally occurring antibodies in the ABO blood group system. These antibodies are what can cause a blood type to be rejected by the body. 
  • Match Run: A computerized ranking of transplant candidates based upon donor and candidate medical compatibility and criteria defined in OPTN policies.

Click here to search the OPTN glossary

Read the full proposal

Provide feedback

eye iconComments

Steven Weitzen | 01/29/2023

If this will increase likelihood of better outcomes for the pediatric community, I believe it should move forward.

Melanie Everitt | 01/25/2023

Supportive of increasing the age eligible for ABOi to <18 yrs. I also support increasing the age for primary allocation from <1 yr for primary offers to <2 yrs for intended ABOi hearts given the waitlist mortality in the <2 yr old cohort.

Deipanjan Nandi | 01/23/2023

Anything that increases the ability to transplant these smaller children should be considered, including this expansion of ABO(i) potential transplants, and I am strongly in favor. While I recognize that the historical data would imply that 1:16 would not be widely sought in the older children transplants, why not leave that a question for individual programs? Some sites choose to accept transplant across known HLA types, and the intricacies of brief rises in PRA and isoheme titers just after a surgical palliation or VAD are best known by individual sites.