Modify Lung Allocation by Blood Type

At a glance

Current policy

In lung allocation, candidates receive a composite allocation score (CAS), which takes into account many patient and donor factors. This score sets the order in which candidates are ranked to receive offers for donor lungs. One of the factors in the score is blood type. Candidates who are less likely to match with donors based on blood type are given more points. Blood type O candidates have received fewer transplants than was expected based on simulation modeling of the policy before it went into effect.

Presentation

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Proposed changes

• Scale up blood type points in the CAS as follows:
  • Type O – 5 points
  • Type B – 2.2382 points
  • Type A – 0.3032 points
  • Type AB – 0 points
• Change shape of rating scale so blood type points have a larger impact on the overall score

Anticipated impact

• What it's expected to do
  • Change the points given to candidates for blood type in lung allocation to provide more proportional access to transplant by blood type
  • Balance against the impact on overall waiting list mortality and median travel distance
• What it won't do
  • Give blood type O candidates extra access to transplant over other blood types

Terms to know

• Composite Allocation Score (CAS): The total number of points assigned to a candidate on the wait list, which would determine their rank on a match run.
• Rating Scale: Method used to calculate number of points awarded to candidates for each attribute. For example, if everything else is equal, should a candidate with twice as much medical urgency as another receive twice as many points? Applying the rating scale to each candidate’s information and combining it with the weight of the attribute results in an overall composite score for prioritizing candidates.
• Blood type (ABO): A classification of blood based on the presence and absence of antibodies and inherited antigenic substances on red blood cells.

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Read the full proposal (PDF)