gastroenterology & hepatologyformula

MELD-Na

MELD-Na incorporates serum sodium into the standard MELD score to improve mortality prediction in cirrhosis. Hyponatraemia is common in advanced cirrhosis (dilutional, from portal hypertension) and is an independent predictor of waitlist mortality that standard MELD does not capture.

inputs

Values <125 set to 125, >137 set to 137 per formula
mmol/L

✓ when to use

Use instead of standard MELD for all patients being evaluated for liver transplant listing. MELD-Na has been the UNOS allocation score since January 2016. Also useful for prognostic discussions in advanced cirrhosis with hyponatraemia.

✗ when not to use

MELD-Na sodium adjustment only applies when MELD ≥11. Below MELD 11, MELD-Na equals MELD. Same limitations as standard MELD regarding renal impairment from non-hepatic causes and warfarin-elevated INR. Not validated in acute liver failure.

clinical pearls

  • Sodium is bounded at 125–137 in the formula. Values below 125 are capped because the relationship between sodium and mortality plateaus at severe hyponatraemia, and extremely low values may reflect lab error or acute water intoxication rather than liver disease severity.
  • The sodium adjustment only applies when base MELD ≥11. Below this threshold, the sodium correction has minimal impact and is not applied.
  • In practice, MELD-Na most significantly reclassifies patients with MELD 15–25 who have hyponatraemia — moving them higher on the transplant list compared to MELD alone. This is the population where sodium adds the most prognostic information.
  • Hyponatraemia in cirrhosis is usually dilutional (hypervolaemic hyponatraemia from impaired free water excretion). It reflects severity of portal hypertension and is a marker of advanced disease, not a target for aggressive sodium correction.
  • UNOS now uses MELD 3.0 (adopted 2022), which includes sex and albumin in addition to the MELD-Na components. Check current allocation policy for the most up-to-date score.

related tools

meldBase MELD score without sodiumchild-pughClinical staging of cirrhosis