UNOS, OPTN & Liver Allocation

In the United States, liver allocation operates through the Organ Procurement and Transplantation Network (OPTN), a federally designated network that establishes national transplant policy and maintains the rules for organ allocation. [1]

UNOS (United Network for Organ Sharing) is the OPTN contractor and administers the OPTN’s day-to-day operations, including the national waiting list and organ matching systems. [1]

For patients, this means your transplant center does not “invent” allocation rules. Your center follows OPTN policy, and organs are offered using a national match system that ranks candidates based on urgency and policy-defined factors. [2]

The modern U.S. transplant system is rooted in the National Organ Transplant Act (NOTA) of 1984, which created a national framework for organ allocation and prohibited buying or selling human organs. [3]

The OPTN is overseen by HRSA (Health Resources and Services Administration), a U.S. Department of Health and Human Services agency that manages the federal oversight of organ donation and transplantation. [4]

A practical way to think about the system:

• OPTN = the policy framework (rules, committees, governance, public comment processes). [2]
• UNOS = the organization contracted to administer the OPTN and operate the matching/waitlist infrastructure. [1]
• HRSA = federal oversight of the national system. [4]

Policies evolve; HRSA has also published information about ongoing OPTN modernization efforts aimed at reliability, safety, and transparency. [5]

Most adult liver candidates are prioritized using the MELD (Model for End-Stage Liver Disease) score, which is designed to estimate short-term risk of death without transplant. [6]

The concept of MELD-based allocation is widely described as a “medical urgency” model, where higher MELD generally means higher priority for offers (with specific policy-defined exceptions and statuses). [7]

Importantly, MELD is not the only determinant: allocation also considers compatibility (such as blood type), candidate status categories, and distribution rules (including distance-based frameworks). [8]

When a donor liver becomes available, the OPTN system generates a ranked “match run” and offers the organ in sequence according to OPTN liver allocation policy. [8]

Your transplant program evaluates whether a specific organ is medically appropriate for you at that time (donor factors, recipient stability, surgical logistics). A decline by the center is not the same as “you were rejected”—it often reflects safety, timing, or suitability decisions. [2]

Liver distribution uses distance from the donor hospital as part of how offers are prioritized (rather than relying only on older fixed geographic boundaries). A widely described framework uses distance-based groupings such as 150, 250, and 500 nautical miles before broader national sharing in certain contexts. [9]

In plain language: a high-urgency candidate farther away may be offered an organ before a lower-urgency candidate nearby, depending on the policy category and the match run sequence. [8]

The goal of these policies is to reduce disparities while balancing travel time, organ preservation, and appropriate prioritization. [10]

Some patients have urgent transplant needs that MELD may not fully capture. OPTN policy allows for MELD exception pathways in defined scenarios—most notably for certain hepatocellular carcinoma (HCC) criteria—using standardized guidance and review processes. [11]

Exception processes are policy-governed and typically require documentation, ongoing reassessment, and center compliance with OPTN requirements. [2]

OPTN policy permits patients to be registered at more than one transplant hospital (multiple listing), although individual centers may set their own acceptance rules for multiple-listed candidates. [12]

Multiple listing can add travel and coordination complexity. If you are considering it, ask about organ offer logistics, insurance coverage, and the practical realities of getting to the hospital quickly if an offer occurs. [12]

• What is my current MELD score, and how often is it recalculated and updated in the OPTN system? [6]
• Do I qualify for any MELD exceptions, and how does my center submit and track exception requests? [11]
• How does distance-based distribution affect my likelihood of getting an offer at this center (given my blood type and MELD)? [8]
• If I want to consider multiple listing, what would your program require and what practical barriers should I anticipate? [12]