Abstract: FR-PO1010
Increasing Early Out-of-Sequence Allocation of Unilateral Deceased-Donor Kidneys
Session Information
- Transplantation: Clinical - Pretransplantation, Living Donation, and Policies
November 07, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Transplantation
- 2102 Transplantation: Clinical
Authors
- Yu, Miko, Columbia University, New York, New York, United States
- Husain, Syed Ali, Columbia University, New York, New York, United States
- Cron, David C., Massachusetts General Hospital, Boston, Massachusetts, United States
- Adler, Joel Thomas, Dell Seton Medical Center at The University of Texas, Austin, Texas, United States
- Schold, Jesse D., University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
- Mohan, Sumit, Columbia University, New York, New York, United States
Background
Deceased donor kidney allocation follows an objective algorithm to match recipients, however organ procurement organizations (OPOs) are increasingly turning to the out-of-sequence (OOS) pathway, citing increased efficiency & utility of less-than-ideal organs. This process lacks standardization & organs can be deemed OOS at any point in the match run.
Methods
Using SRTR registry data from 2020-24, we identified donor pairs with one kidney successfully placed in-sequence with the other placed OOS. We examined the prevalence of unilateral OOS allocation & compared the sequence numbers of the first appearance of an OOS code.
Results
4,313 donor pairs were identified with unilateral OOS transplants, representing 28% of all OOS kidneys. There was a 17-fold increase in the number of unilateral OOS kidneys rising from 97 instances in 2020 to 1,698 kidneys in 2024 (Fig 1). 15 OPOs offered a total of 97 unilateral OOS organs in 2020 at median sequence number 202 (IQR 40-513) compared to all 56 OPOs offering 1,698 unilateral OOS organs in 2024 at median sequence number 28 (IQR 21-46) in 2024. Those allocated OOS before sequence 100 had a higher proportion of recipient factors cited & a 10-15% lower proportion of donor-related factors such as organ damage, biopsy or donor history.
Conclusion
OOS transplants have increased rapidly & more than a third of these are unilateral OOS following the successful in-sequence placement of the mate kidney, with OPOs allocating these organs OOS earlier in the match run each year. Understanding if this practice is truly driven by concerns of donor quality is critical to determining next steps in the development of an expedited pathway for organs at risk of nonuse.
Number of kidneys transplanted & median sequence numbers of the first appearance of an OOS refusal code.
Funding
- NIDDK Support