MELD stands for Model for End-Stage Liver Disease. It uses three objective lab values (bilirubin, INR, creatinine) to predict 3-month mortality in patients with liver disease. Scores range from 6 to 40, with higher scores indicating more severe disease.

MELD-Na incorporates serum sodium into the MELD calculation, which improves mortality prediction — especially for patients with ascites and dilutional hyponatremia. Since 2016, UNOS has used MELD-Na for liver transplant allocation in the US.

Higher MELD scores indicate greater urgency for transplantation. In general: MELD <10 has good prognosis without transplant; MELD 10–19 represents moderate disease; MELD 20–29 represents increasing mortality; MELD ≥30 indicates very severe disease with high short-term mortality.

MELD may not capture all aspects of liver disease severity. It can underestimate risk in patients with certain conditions like hepatocellular carcinoma, hepatopulmonary syndrome, or persistent ascites. Exception points are sometimes granted for conditions not reflected in the score.