Allocation Out of OPTN Sequence (AOOS)

AOOS is when an organ is offered or accepted or transplanted into a transplant candidate or potential transplant recipient (PTR) that deviates from the match sequence and is not consistent with OPTN policy.

AOOS is identified through the use of one or more of the following organ offer bypass codes:

• 861: Operational - Organ Procurement Organization (OPO)
• 862: Donor medical urgency
• 863: Offer not made due to expedited placement attempt
• 887: Not Offered - expedited placement
• 799: Other (specify)

HRSA and the OPTN are committed to data transparency and accessibility. With HRSA’s support, the OPTN is developing a consensus, living dataset for the community to use in AOOS analyses; when that dataset is available, these graphs and the details below will be updated accordingly.

Please contact AskDOT@HRSA.gov with questions about this analysis or suggestions for how to improve future versions of this dashboard.

Allocation out of sequence

• This graph shows the percent of organ allocations that met the OPTN’s analytic definition of AOOS.
• The “All OPOs (Median)” line shows the median AOOS rate by OPO for each month. The individual OPO lines show a rolling average over the previous six months. To protect patient privacy, data points that would be calculated from fewer than 15 total allocation events are not shown.
• The full organ donation, procurement, and transplant process can take several days. In this graph, the date of an organ’s allocation is counted as the date when an OPO executed a match run to determine the sequence of potential recipients who would be offered that organ.
• An allocation is considered out of sequence if one or more of the AOOS organ offer bypass codes was recorded for a potential transplant recipient ranked earlier on the match run than the patient who accepted the organ. An allocation is not considered out of sequence if AOOS bypass codes are present only at later sequences than the patient who accepted the organ. (Note that in rare cases, the patient who accepts the organ may not be the patient who receives the transplant.)
• Sometimes more than one refusal or bypass code is entered in response to a single organ offer. This analysis considers the latest code entered for each offer, which may have been recorded by an OPO, a transplant center, or the OPTN computer system.
• OPOs are required to report organ offer outcomes, including bypass codes, within 30 days of the match run date. (See OPTN Policy 18.3 (PDF - 3 MB) for more detail.) Because data are largely incomplete within this 30-day reporting period, this graph shows results with a one-month delay from the date of analysis.
• Sometimes an OPO runs more than one match run for the same organ(s). In this analysis, most allocations are counted once per organ:
  • If the organ was transplanted, we count the match run used to allocate the organ for transplant.
  • If the organ was accepted but not transplanted, we count the latest match run on which it was accepted.
  • Organs that were offered but neither accepted nor transplanted are not included in this graph because offers cannot be characterized as in or out of sequence using existing OPTN allocation data.
  • Multi-organ transplants allocated on a single match run are counted as a single allocation event. For example, if a recipient is allocated a lung on a lung match run and also receives a kidney from the same donor as part of a multi-organ transplant, that allocation is counted once.
  • Separately transplanted organs allocated on the same match run (for example, two kidneys from the same donor into separate recipients) are counted as separate allocation events.
• This analysis includes the following organs: kidney, pancreas, liver, intestine, heart, lung. This analysis excludes islet cell and vascularized composite allotransplantation (VCA) transplants.
• This analysis only includes organs procured and transplanted in the U.S. From 2015 to 2024, an average of <10 organs per year were procured outside the U.S. and transplanted in the U.S.
• An allocation event is counted for the OPO that submitted the match run, even in rare cases where this is not the same OPO that performed the procurement surgery.

Organ non-use

• This graph shows the proportion of all organs procured for transplant that were not ultimately transplanted.
• The “All OPOs” line shows the median organ non-use rate by OPO for each month. The individual OPO lines show a rolling average over the previous six months. To protect patient privacy, data points that would be calculated from fewer than 15 total allocation events are not shown.
• The full organ donation, procurement, and transplant process can take several days. In this graph, the date of an organ’s use or non-use is counted as the date of the organ recovery surgery.
• An organ use/non-use event is counted for the OPO that performed the procurement surgery, even in rare cases where a different OPO executed a match run for that organ.

• National Organ Transplant Act
• Final Rule
• OPTN Bylaws and Policies