Current policy
Every lung transplant candidate receives an individualized lung Composite Allocation Score (CAS). This score determines priority for receiving a lung transplant when donor lung(s) become available. The lung CAS is individual for each candidate and each organ offer. The lung CAS point values represent each of the factors used to match organ offers with transplant candidates (Exhibit 1). The people who have the highest number of points for that organ offer will have the highest priority.
In October 2025, the Health Resources and Services Administration’s (HRSA) preliminary analyses documented a rise in allocation out of OPTN sequence (AOOS) that correlates with the implementation of the lung continuous distribution policy in 2023. In response, the OPTN Board of Directors considered potential changes to lung allocation to promote policy compliance and reduce AOOS.
Supporting media
Exhibit 1. Current Lung Composite Allocation Score
| Attribute | Definition | % of Available Points |
|---|---|---|
| Waiting List Survival | Expected 1-year waiting list survival | 25 |
| Post-Transplant Outcomes | Expected 5-year post-transplant survival | 25 |
| Candidate Biology | Total of ABO, CPRA, and height points | 15 |
| ABO | Based on percentage of compatible donors by blood type | 5 |
| CPRA | Based on percentage of compatible donors by CPRA | 5 |
| Height | Based on percentage of compatible donors by height | 5 |
| Patient Access | Total of pediatric and prior living donor points | 25 |
| Pediatric | For candidates under 18 years old | 20 |
| Prior Living Donor | For candidates who donated any organ | 5 |
| Placement Efficiency | Total of travel and proximity efficiency points | 10 |
| Travel Efficiency | Based on impact of distance on costs of travel | 5 |
| Proximity Efficiency | Based on impact of distance on other efficiency (time, availability, etc.) | 5 |
Note. Total Score = Waiting List Survival + Post-Transplant Outcomes + Candidate Biology + Patient Access + Placement Efficiency
Acronyms. ABO=ABO blood group system, CPRA=Calculated Panel Reactive Antibody
Proposed changes
- Increasing the weight on placement efficiency from 10% to 15% of the overall score.
- Reducing the weight on all other parts of the score proportionally, including points assigned to pediatric candidates less than 12 years old for waitlist survival and post-transplant outcomes.
- Replacing the existing travel efficiency and proximity efficiency rating scales with a single placement efficiency rating scale to assign points to potential transplant recipients based on the nautical mile distance between the donor hospital and the transplant hospital.
- Lung CAS scores for all lung and heart-lung candidates on the waiting list will be updated to reflect the changes to the lung CAS (Exhibit 2).
- Approved exceptions will remain in effect based on the percentage of available points approved by the Lung Review Board, and the points assigned for each exception will be reduced proportionately to the adjusted goal weights.
Exhibit 2. Revised Lung Composite Allocation Score
| Attribute | Definition | % of Available Points |
|---|---|---|
| Waiting List Survival | Expected 1-year waiting list survival | 23.6111 |
| Post-Transplant Outcomes | Expected 5-year post-transplant survival | 23.6111 |
| Candidate Biology | Total of ABO, CPRA, and height points | 14.1666 |
| ABO | Based on percentage of compatible donors by blood type | 4.7222 |
| CPRA | Based on percentage of compatible donors by CPRA | 4.7222 |
| Height | Based on percentage of compatible donors by height | 4.7222 |
| Patient Access | Total of pediatric and prior living donor points | 23.6111 |
| Pediatric | For candidates under 18 years old | 18.8889 |
| Prior Living Donor | For candidates who donated any organ | 4.7222 |
| Placement Efficiency | Total of travel and proximity efficiency points | 15 |
Note. Total Score = Waiting List Survival + Post-Transplant Outcomes + Candidate Biology + Patient Access + Placement Efficiency
Acronyms. ABO=ABO blood group system, CPRA=Calculated Panel Reactive Antibody
Anticipated impact
- What it's expected to do
- Reduce median travel distance for lungs
- Reduce logistical complexity in lung allocation
- Improve policy compliance
- What it won’t do
- It will not completely alleviate AOOS.
Terms to know
- Allocation out of OPTN sequence (AOOS): An organ allocation event in which an organ is offered, accepted, and/or transplanted outside the established match sequence.
- Composite Allocation Score (CAS): This score determines priority for receiving a lung transplant when donor lung(s) become available.
- Calculated Panel Reactive Antibody (CPRA): A score (0–100%) indicating the percentage of potential donors a patient is immunologically incompatible with due to antibodies.
Read the full proposal (PDF - 377 KB)
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