MELD Score
The Model for End-Stage Liver Disease (MELD) is a scoring system used to prioritize patients on the liver transplant wait list. The MELD score can be calculated by using routine blood tests including bilirubin, INR (International Normalized Ratio, or prothrombin time), and creatinine to estimate how sick the liver is. When your sodium levels are used in the calculation, the score is called MELD-Na.
For adults and children aged 12 and older, MELD/MELD-Na scores usually range from 6 to 40. These scores are not specific to PSC, but are used for all liver conditions when determining if someone should be listed for a liver transplant. In most cases a higher score indicates more severe liver damage and thus a higher priority for transplant. However, this is not necessarily the case with PSC patients.
PELD Score
The Pediatric Model for End-Stage Liver Disease (PELD) is the pediatric version of MELD, and is used for children under 12 years of age. It is based on albumin, bilirubin, INR, growth failure, and age at transplant listing.
How the scores relate to PSC and eMELD and ePELD
The MELD and PELD scores are important, however they do not always tell the full story for PSC patients. Some patients may be much sicker or have serious symptoms or complications that are not fully reflected in their scores. Because of this, some PSC patients may receive exception points to add to their MELD and PELD scores to make eMELD and ePELD scores. These exception points can help provide a more accurate picture of the severity of their liver disease and adjust one’s priority on the transplant list.
Relevance of exception points in Canada
In Canada, transplant practices can differ by province, so the way exception points are handled may vary depending on where you live. A Canadian Liver Journal review describes these provincial differences in more detail (see Tables 2, 3, and 4) in their article Exception points for liver transplantation: A Canadian review.
Calculating individual MELD or PELD scores
For patients with PSC, understanding your MELD/PELD (or eMELD/ePELD scores) is important when discussing the need for transplant with your doctor. The Organ Procurement and Transplantation Network posted an online calculator for calculating your MELD or PELD score based on the blood test results you input. When using this online calculator, it is important to review the results with your doctor.
Use of machine learning to evaluate liver transplant priorities
Although the eMELD and ePELD scores are used to help address the disparities in liver transplantation, they are still not perfect. Fortunately, Dr. Mamatha Bhat from the University Health Network in Toronto is working to use machine learning to address these disparities in people with PSC. By using both the MELD score and PSC-specific factors (for example: frequency of cholangitis, cirrhosis, biliary dysplasia and removal surgeries), this tool has the potential to better reflect the true medical need of transplant for those with PSC.
For more information, read Using Machine Learning to Evaluate Liver Transplant Priorities. The full paper – Living donor liver transplantation can address disparities in transplant access for patients with primary sclerosing cholangitis – is available on the National Library of Medicine website.
