MELD Score Explained: Liver Disease Severity & Transplant Priority
Quick Answer
- *The MELD score is a number from 6–40 that measures how severely the liver is failing, using bilirubin, INR, and creatinine levels to estimate 90-day mortality risk.
- *UNOS uses MELD score to rank patients on the liver transplant waiting list — higher scores receive priority organ offers.
- *The updated MELD-Na formula, adopted in 2016, adds serum sodium to more accurately predict waitlist mortality.
- *A MELD score of 40 or above is associated with approximately 71% 90-day mortality without transplantation.
What Is the MELD Score?
The MELD score — Model for End-Stage Liver Disease — is a numerical scoring system that quantifies the severity of chronic liver disease in adults. It was originally developed at the Mayo Clinic in 2001 by Dr. Patrick Kamath and colleagues to predict 90-day survival in patients undergoing elective placement of a transjugular intrahepatic portosystemic shunt (TIPS). Researchers quickly recognized that the score was broadly predictive of short-term mortality in any patient with end-stage liver disease.
In 2002, the United Network for Organ Sharing (UNOS) and the Organ Procurement and Transplantation Network (OPTN) adopted MELD as the primary metric for allocating deceased-donor livers in the United States, replacing the older Child-Pugh score system. The shift was significant: rather than clinical judgment or time on the waiting list, organ allocation would now be driven by objective, lab-based urgency.
The MELD Formula
The standard MELD score uses three laboratory values:
- Serum bilirubin (mg/dL) — a marker of the liver's ability to process waste products
- INR (International Normalized Ratio) — a measure of clotting ability, reflecting synthetic function of the liver
- Serum creatinine (mg/dL) — a marker of kidney function, which deteriorates in advanced liver disease
The formula is:
MELD = 3.78 × ln(bilirubin) + 11.2 × ln(INR) + 9.57 × ln(creatinine) + 6.43
Where ln() is the natural logarithm. Lab values below 1.0 are rounded up to 1.0 before calculation to avoid negative contributions. Creatinine is capped at 4.0 mg/dL. The score is typically rounded to the nearest whole number and ranges from 6 to 40 (scores above 40 are treated as 40 for allocation purposes).
You do not need to do this math by hand. Our MELD Score Calculator handles the computation automatically.
MELD Score Ranges and 90-Day Mortality
The score is directly correlated with short-term mortality risk. The following table summarizes 90-day mortality estimates by MELD range, based on outcomes data published in the original Mayo Clinic derivation study and subsequent OPTN analyses:
| MELD Score | 90-Day Mortality Estimate | Clinical Interpretation |
|---|---|---|
| Less than 10 | ~2% | Relatively stable; outpatient management typical |
| 10–19 | ~6% | Moderate disease; close monitoring required |
| 20–29 | ~20% | Serious disease; transplant evaluation often initiated |
| 30–39 | ~52% | Advanced failure; high transplant urgency |
| 40 or above | ~71% | Critical; highest priority on transplant list |
These are population-level estimates. Individual outcomes depend on the underlying etiology of liver disease, comorbidities, nutritional status, and response to treatment. A physician must interpret any MELD score in the full clinical context.
MELD-Na: The Updated Formula Used Since 2016
In January 2016, UNOS replaced the standard MELD score with MELD-Na as the official allocation tool. MELD-Na adds serum sodium to the formula because hyponatremia (low sodium) is independently associated with increased waitlist mortality in cirrhotic patients, even when the standard MELD score is the same.
The MELD-Na formula adjusts the standard MELD score using:
MELD-Na = MELD + 1.32 × (137 − sodium) − [0.033 × MELD × (137 − sodium)]
Sodium values used in this formula are capped between 125 and 137 mEq/L. The practical effect: a patient with a MELD of 18 and sodium of 128 mEq/L will receive a higher MELD-Na score than a patient with MELD of 18 and normal sodium, reflecting their higher actual mortality risk.
The adoption of MELD-Na represented a meaningful policy change. A 2008 study in Hepatologyfound that adding sodium to the MELD score improved the concordance statistic (c-statistic) for 90-day waitlist mortality from 0.87 to 0.90 — a statistically significant improvement in predictive accuracy.
How UNOS Uses MELD for Organ Allocation
When a deceased-donor liver becomes available, UNOS runs a match algorithm that ranks waiting patients by MELD-Na score within defined geographic zones. Patients with the highest scores receive priority offers first. This system was designed to allocate livers to patients with the highest short-term mortality risk who are most likely to benefit from transplantation.
Key allocation statistics from OPTN data:
- As of 2024, approximately 10,000 patients are on the U.S. liver transplant waiting list at any given time (OPTN data).
- Roughly 9,400 liver transplants are performed annually in the United States (OPTN 2023 annual report).
- The median MELD score at transplant has hovered around 20–24 in recent years, reflecting the practical threshold where transplant benefit exceeds ongoing disease risk.
- Patients with MELD below 15 rarely receive transplants under the current system because post-transplant survival benefit is less clear at lower disease severity.
UNOS also allows for exception points in specific conditions like hepatocellular carcinoma (HCC), where the MELD score alone may underestimate true mortality risk. Transplant centers can petition for additional points through a regional review board process.
Why the MELD Score Was Developed: Key Background Statistics
Liver disease is a significant public health burden in the United States:
- The CDC estimates that approximately 4.5 million adults in the U.S. have been diagnosed with liver disease (CDC chronic liver disease data, 2022).
- Cirrhosis and chronic liver disease account for approximately 56,000 deaths annually in the United States (CDC, 2021 mortality data).
- MELD was developed at Mayo Clinic in 2001 and published in Hepatology by Kamath et al. The original paper remains one of the most cited in hepatology literature.
- UNOS adopted MELD for allocation in February 2002, replacing the Child-Turcotte-Pugh (CTP) score which had been used since the 1990s.
- MELD-Na was adopted as the official allocation metric in January 2016 after multiple validation studies demonstrated improved predictive accuracy.
MELD Score in Specific Liver Diseases
Alcoholic Hepatitis
In severe alcoholic hepatitis, MELD score helps guide treatment decisions. A MELD above 20 in this context often indicates consideration for corticosteroid therapy (prednisolone). MELD score can also track response to treatment over a 7-day period; failure to improve (Lille score) informs further management.
Hepatitis C and Antiviral Therapy
With the advent of direct-acting antiviral (DAA) therapy for hepatitis C, many patients who previously faced transplantation have seen MELD scores fall significantly after achieving sustained virologic response (SVR). This demonstrates the dynamic nature of the score.
Non-Alcoholic Fatty Liver Disease (NAFLD)
NAFLD is now the leading cause of liver disease in the U.S. As NAFLD progresses to cirrhosis, MELD scoring becomes increasingly relevant for monitoring disease progression and transplant planning.
Limitations of the MELD Score
MELD is a powerful but imperfect tool. Important limitations include:
- Lab variability: Different laboratories may produce slightly different creatinine or bilirubin readings, affecting the score.
- Acute vs. chronic disease: MELD was derived in patients with chronic liver disease and may behave differently in acute liver failure.
- Doesn't capture all causes of mortality: Frailty, ascites severity, hepatic encephalopathy, and muscle wasting all affect outcomes but aren't directly reflected in the score.
- Exception scores: The need for disease-specific exception point requests (e.g., HCC) reflects that MELD alone doesn't capture every relevant clinical scenario.
Researchers continue to investigate alternative or supplemental scores. The MELD 3.0 formula, published in 2021, adds female sex, albumin, and sodium to improve equity and accuracy, particularly for women who historically have faced higher waitlist mortality at equivalent MELD scores.
Calculate a MELD score from lab values
Use our free MELD Score Calculator →For educational reference only — always consult your physician for clinical interpretation.
Frequently Asked Questions
What is a MELD score and what does it measure?
MELD (Model for End-Stage Liver Disease) is a numerical score from 6 to 40 that measures the severity of chronic liver disease. It uses three lab values — bilirubin, INR, and creatinine — to estimate 90-day mortality risk. Higher scores indicate more severe disease and greater urgency for liver transplantation.
What MELD score qualifies for a liver transplant?
There is no single cutoff score that automatically qualifies someone for transplant. UNOS uses MELD score to prioritize patients on the waiting list — patients with higher scores receive priority. In practice, most transplants occur in patients with MELD scores above 15, and urgency increases significantly above 20.
What is MELD-Na and how is it different from regular MELD?
MELD-Na adds serum sodium to the standard MELD formula to better predict 90-day waitlist mortality. UNOS adopted MELD-Na as the official allocation score in January 2016 after studies showed sodium levels independently predicted mortality in cirrhotic patients. Patients with low sodium levels receive a higher effective score.
How is the MELD score formula calculated?
The MELD formula is: 3.78 × ln(bilirubin) + 11.2 × ln(INR) + 9.57 × ln(creatinine) + 6.43. All lab values below 1.0 are rounded up to 1.0 before calculation. Creatinine is capped at 4.0 mg/dL. The result is rounded to the nearest whole number.
What is a normal or good MELD score?
MELD scores range from 6 to 40. A score below 10 is associated with approximately 2% 90-day mortality and reflects relatively stable liver function. Scores of 10 to 19 suggest moderate disease with about 6% 90-day mortality. Any score above 20 indicates serious disease requiring close medical management.
Can a MELD score improve?
Yes. MELD score is dynamic and can improve if the underlying cause of liver disease is treated. Patients with alcoholic hepatitis who stop drinking, or hepatitis C patients who achieve viral clearance with antiviral treatment, may see significant score reductions. Treatment of infections and optimizing nutrition can also lower MELD.