MELD-Na Score
Model for End-stage Liver Disease incorporating sodium, for chronic liver disease severity and transplant priority.
MELD-Na quantifies the severity of chronic liver disease and is used by allocation systems to prioritise liver transplantation. It refines the original MELD by adding serum sodium, which independently predicts mortality in cirrhosis.
📐 Formula
MELD = 3.78·ln(bili) + 11.2·ln(INR) + 9.57·ln(creat) + 6.43; MELD-Na = MELD + 1.32·(137 − Na) − 0.033·MELD·(137 − Na)
🎯 When to Use
- Assessing severity of chronic liver disease and cirrhosis.
- Estimating 3-month mortality for transplant listing and prioritisation.
- Serial tracking of decompensation.
⚙️ How It Works
- Each of bilirubin, INR and creatinine is bounded to a minimum of 1.0 before taking the natural log.
- Creatinine is capped at 4.0 mg/dL (and set to 4.0 for patients on dialysis).
- MELD = 3.78·ln(bilirubin) + 11.2·ln(INR) + 9.57·ln(creatinine) + 6.43.
- Sodium is bounded to 125–137 mEq/L, then MELD-Na = MELD + 1.32·(137 − Na) − 0.033·MELD·(137 − Na).
📊 Interpreting the Result
- MELD-Na ≤ 9: ~1.9% estimated 3-month mortality.
- MELD-Na 10–19: ~6% estimated 3-month mortality.
- MELD-Na 20–29: ~20% estimated 3-month mortality.
- MELD-Na 30–39: ~53% estimated 3-month mortality.
- MELD-Na ≥ 40: ~71% estimated 3-month mortality.
⚠️ Limitations & Pitfalls
- Validated for patients ≥12 years old; not for acute liver failure.
- Laboratory values must be recent and consistent; medications and haemolysis can distort inputs.
- The sodium correction is only applied when the base MELD exceeds 11 in the OPTN implementation.
📚 References
- Kim WR, Biggins SW, Kremers WK, et al. Hyponatremia and mortality among patients on the liver-transplant waiting list. N Engl J Med. 2008;359(10):1018-1026.
- Organ Procurement and Transplantation Network (OPTN) Policy — MELD/PELD calculation.
⚕️ For clinical decision support only. Always verify calculations and apply clinical judgment.