MELD-Na Score = —
Calculator Use
The meld score calculator is an essential clinical tool used to estimate the relative severity of chronic liver disease. Standing for "Model for End-Stage Liver Disease," the MELD score is primarily used by United Network for Organ Sharing (UNOS) and other medical organizations to prioritize patients for liver transplants. By entering specific laboratory values, you can determine a score that predicts the 3-month survival rate of patients with cirrhosis.
This version utilizes the MELD-Na formula, which incorporates serum sodium levels. Studies have shown that adding sodium to the original MELD calculation provides a more accurate prediction of mortality, as hyponatremia (low blood sodium) is a significant risk factor in end-stage liver disease.
- Bilirubin
- Measures how well the liver clears bile. Higher levels often indicate liver dysfunction.
- INR (International Normalized Ratio)
- Evaluates the blood's ability to clot, which depends on proteins produced by the liver.
- Creatinine
- A marker of kidney function. Kidney failure is common in advanced liver disease (hepatorenal syndrome).
- Sodium
- Helps assess fluid balance and electrolyte status, critical for predicting complications.
How It Works
The MELD score calculation relies on logarithmic values of laboratory results. Because different labs have different minimums, the formula "caps" or "floors" certain values (e.g., values less than 1.0 are treated as 1.0) to maintain statistical consistency. The modern formula used by UNOS since 2016 is:
MELD(i) = 0.957 × ln(Cr) + 0.378 × ln(Bil) + 1.120 × ln(INR) + 0.643
If the MELD(i) is greater than 11, the calculator performs the Sodium correction (MELD-Na):
MELD-Na = MELD(i) + 1.32 × (137 – Na) – [0.033 × MELD(i) × (137 – Na)]
- Dialysis: If a patient has received dialysis twice within the last 7 days, the Creatinine value is automatically set to 4.0 mg/dL.
- Maximum Score: The MELD score is capped at 40. Patients with scores of 40 are given the highest priority.
- Minimum Score: The score is floored at 6.
Calculation Example
Example: A 55-year-old patient with cirrhosis presents with the following lab results: Bilirubin 3.0, INR 1.8, Creatinine 1.5, and Sodium 130.
Step-by-step solution:
- Calculate base MELD(i): 0.957*ln(1.5) + 0.378*ln(3.0) + 1.120*ln(1.8) + 0.643 = 2.11
- Multiply by 10: 21.1
- Apply Sodium Correction (since 21.1 > 11): 21.1 + 1.32*(137-130) – [0.033*21.1*(137-130)]
- 21.1 + 9.24 – 4.87 = 25.47
- Round to the nearest whole number: MELD-Na = 25
Common Questions
What is a "good" MELD score?
In the context of the MELD score, lower is better. A score of 6 to 9 indicates mild liver dysfunction with a very low 3-month mortality risk. As the score increases, the urgency for a transplant increases.
How often should MELD be recalculated?
The frequency depends on the score's severity. Patients with a score of 25 or higher often require lab updates every week, while those with scores below 10 may only need updates once a year for transplant list maintenance.
Does the MELD score consider liver cancer?
The meld score calculator itself measures liver function, not cancer specifically. However, patients with Hepatocellular Carcinoma (HCC) may receive "exception points" to increase their score and priority on the transplant list, as their mortality risk is higher than their lab values might suggest.