UNOS, MELD, and PELD
In the United States, the United Network for Organ Sharing (UNOS) is the national organization that sets policy and enforces the rules for organ allocation. UNOS rules determine when and to whom organs are allocated. All transplant centers must abide by UNOS rules to remain certified to perform transplants. UNOS divides the country into 11 distinct organ sharing regions as shown on this map.
MELD/PELD: For liver candidates, UNOS has developed a scoring system called MELD (Model End-Stage Liver Disease) to determine the need for a liver. The scoring system is based upon blood tests for bilirubin, creatinine, and INR (International Normalized Ratio, also called prothrombin time). MELD scoring also includes serum sodium levels. Scores range from 6 (low level of illness) to 40 (gravely ill). For persons under the age of 12, the calculator is called PELD (Pediatric End-Stage Liver Disease). The PELD score includes age, bilirubin, albumin, INR, and history of growth failure.
The MELD/PELD system has reduced the number of deaths of people on the waiting list by offering livers for the sickest patients. Researchers have found that transplantation too early, at a low MELD score, can prematurely expose the person receiving the transplant to higher operative and immunosuppressive risks associated with the transplant surgery.
Waiting Time: The waiting time for liver transplantation varies depending on how sick the individual is, which is usually reflected by their MELD or PELD score. In addition, blood type is also important in the matching process, and body type may play a role. Until 2002, time spent on the waiting list was the determining factor for organ recipients. However, today the MELD and PELD scores identify who is sickest and requires a liver first.
Special Exceptions: For some liver conditions, a special exception can be made to raise the MELD/PELD score. If your doctor thinks you present special circumstances that are unaddressed by the MELD/PELD system, the transplant center can ask a UNOS Regional Review Board for an exception. Exceptions are very rarely given. The hepatologist with whom you are working can explain where you fit in the scoring system.
The UNOS website has a calculation feature page where you can calculate the MELD and PELD score, if you know the values of certain recent blood tests.
Updating Lab Tests: As you get closer to your transplant, you will be required to update blood tests on a specific, required schedule. If you do not keep the tests updated and inform your transplant center, you can be given a lower MELD/PELD score until you get your lab tests done. Your center’s transplant coordinator will help you understand the schedule and assist you in sending the results to the center.
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