About

The Model for End-Stage Liver Disease (MELD) is a reliable numerical scale used by the United Network for Organ Sharing (UNOS) to assess the severity of chronic liver disease. Initially developed to predict death within three months of surgery in patients who had undergone a transjugular intrahepatic portosystemic shunt (TIPS) procedure, it is now the standard for determining liver transplant allocation.

Accuracy in this calculation is a matter of life and death, as the score directly dictates a patient's place on the waitlist. This tool implements the strict UNOS modification, which accounts for lower limits (setting values less than 1.0 to 1.0) to prevent mathematical errors with logarithms, and caps the maximum creatinine level to ensure balanced scoring.

Formulas

The calculation uses natural logarithms (ln). Values for Bilirubin, INR, and Creatinine that are less than 1.0 are set to 1.0. Creatinine is capped at 4.0 mg/dL. If the patient is on dialysis, Creatinine is automatically set to 4.0.

MELD = 10 × (0.957 × ln(Cr) + 0.378 × ln(Bili) + 1.120 × ln(INR) + 0.643)

Reference Data

MELD Score	3-Month Mortality Risk
≤ 9	1.9%
10 - 19	6.0%
20 - 29	19.6%
30 - 39	52.6%
≥ 40	71.3%

Frequently Asked Questions

The MELD score typically ranges from 6 (less ill) to 40 (gravely ill). While the formula can mathematically produce higher numbers, the score is capped at 40 for transplant ranking purposes.

It depends on the score's severity. Patients with a score of 25 or higher must be recertified every 7 days. Scores 19-24 every 30 days, 11-18 every 3 months, and scores 10 or less once a year. The dynamic nature of liver disease requires frequent monitoring.

The UNOS modification ensures consistency. It mandates that any lab value less than 1.0 is rounded up to 1.0 (since the natural log of 0 or a fraction can skew results negatively). It also caps Serum Creatinine at 4.0 mg/dL and considers patients on dialysis (twice in the last week) to automatically have a Creatinine of 4.0.

This specific interface calculates the standard MELD. However, if the MELD score is > 11, UNOS often incorporates Serum Sodium levels (MELD-Na) to further refine mortality risk, particularly for patients with hyponatremia. This tool focuses on the core 3 components.