MELD Formula
The MELD (Model for End-Stage Liver Disease) score is calculated using the formula: MELD = 3.8 × log(bilirubin in mg/dL) + 11.2 × log(INR) + 9.6 × log(creatinine in mg/dL) + 6.4. 1
Formula Components
The MELD score incorporates three objective laboratory values 1:
- Serum bilirubin (mg/dL) - reflects hepatic excretory function 1, 2
- Serum creatinine (mg/dL) - assesses renal function, a critical prognostic marker in liver disease 1
- INR (International Normalized Ratio) - measures coagulation function and clotting factor synthesis 1, 2
Score Range and Interpretation
- The MELD score produces a numeric scale ranging from 6 (less ill) to 40 (gravely ill) for individuals aged 12 years or older 1
- Mortality risk increases directly with MELD score: patients with MELD <9 have 1.9% 3-month mortality, while those with MELD ≥40 have 71.3% mortality 3
- A MELD score ≥18 indicates poor prognosis in alcoholic hepatitis, though cutoffs of 11,19, or 21 have also been suggested depending on clinical context 1
Clinical Applications
Primary use for liver transplant allocation: The MELD score was adopted by the United Network for Organ Sharing (UNOS) in 2002 to stratify patients on the liver transplantation waiting list according to their risk of death within 3 months 1, 3, 4
Prognostic accuracy: The MELD score demonstrates superior predictive ability compared to Child-Pugh score, with a c-statistic of 0.83 versus 0.76 for 3-month mortality prediction 3
Beyond transplant: The score effectively predicts outcomes in cirrhotic patients undergoing surgery, those with fulminant hepatic failure, and patients with alcoholic hepatitis 4
Recent Evolution: MELD 3.0
The newest iteration, MELD 3.0, incorporates additional variables including patient sex and serum albumin levels, with adjusted weights for sodium, bilirubin, INR, and creatinine 5, 6
This update is expected to reduce overall waitlist mortality and improve access for female liver transplant candidates 5, 6
Advantages Over Child-Pugh Score
- Objective scoring based solely on widely available laboratory tests - eliminates subjective clinical assessments 1
- Includes renal function measurement - captures the hepatorenal syndrome component of advanced liver disease 1
- Continuous variable - provides more granular risk stratification than categorical systems 4
Important Limitations
The MELD score does not include clinical parameters such as ascites, encephalopathy, or signs of portal hypertension that are captured in Child-Pugh scoring 1
INR and creatinine elevations from non-hepatic causes can artificially inflate the score, requiring clinical judgment 4
Validation concerns: The MELD score has not been validated as a predictor of survival in cirrhotic patients who are not on a liver transplantation waiting list 1
Practical Calculation Note
An online calculator is available at www.mayoclinic.org/meld/mayomodel7.html for ease of use 1
The formula uses natural logarithms (log base e) for all three laboratory values, with a constant of 6.4 added to the sum 1