Why does MELD-Na include serum sodium?

Hyponatremia (low serum sodium) is a marker of portal hypertension severity and impaired renal free-water excretion, both of which independently predict mortality in cirrhosis. Large cohort studies showed that patients with the same classic MELD score but lower sodium had significantly higher 90-day mortality. Adding sodium to the formula corrects this underestimation, which is why UNOS replaced classic MELD with MELD-Na for allocation in January 2016.

How is MELD-Na calculated?

First, compute classic MELD = 10 × (0.957 × ln(creatinine) + 0.378 × ln(bilirubin) + 1.120 × ln(INR)) + 6.43, with creatinine capped at 4.0, and all three values floored to 1.0. Then apply the sodium adjustment: MELD-Na = MELD + 1.32 × (137 − Na) − [0.033 × MELD × (137 − Na)], with sodium clamped to the 125–137 mEq/L range.

What sodium range does the formula use?

The UNOS formula clamps serum sodium to a minimum of 125 mEq/L and a maximum of 137 mEq/L. Values below 125 are treated as 125 (severe hyponatremia beyond this point adds no further penalty in the formula), and values above 137 are treated as 137 (the sodium adjustment becomes zero at or above 137 mEq/L, so normonatremic patients get no bonus).

What is the minimum MELD-Na score?

The minimum reportable score is 6 per UNOS policy. This floor prevents nonsensical negative scores for very healthy-range laboratory values and ensures all active waitlist candidates have a baseline allocation priority.

Is this tool a substitute for clinical judgment?

No. This calculator is for educational and reference purposes only. MELD-Na scores must be interpreted alongside the full clinical picture — etiology, comorbidities, functional status, and local transplant center criteria. Transplant allocation decisions are governed by national UNOS/OPTN policy and require multidisciplinary teams. Never use any calculator as the sole basis for a medical decision.

When should I use MELD-Na vs. classic MELD?

For official UNOS liver transplant allocation in the United States, MELD-Na is the current standard (since January 2016). Classic MELD is still reported for historical comparison and is used in some non-US systems and in contexts such as Maddrey Discriminant Function combinations for alcoholic hepatitis. This calculator computes both so you can compare them.

MELD-Na Score Calculator

Name: MELD-Na Score Calculator
Availability: InStock
Author: Nham Vu

Enter serum bilirubin, creatinine, INR, and sodium to compute the MELD-Na score and estimate 90-day mortality risk in liver disease.

Lab Values

Serum Bilirubin (mg/dL)

Minimum applied: 1.0 mg/dL per UNOS guidelines

Serum Creatinine (mg/dL)

Capped at 4.0 mg/dL; dialysis patients use 4.0

INR (International Normalized Ratio)

Minimum applied: 1.0 per UNOS guidelines

Serum Sodium (mEq/L)

Formula clamps to 125–137 mEq/L range

MELD-Na Formula (UNOS 2016)

MELD = 10 × (0.957×ln(Cr) + 0.378×ln(Bili) + 1.120×ln(INR)) + 6.43
MELD-Na = MELD + 1.32×(137−Na) − [0.033×MELD×(137−Na)]

Enter lab values on the left and click Calculate MELD-Na Score

MELD-Na Score (UNOS Allocation)

—

Classic MELD

—

Without sodium

Na Adjustment

—

Points added by sodium

Score Position

610203040+

LowMildModerateSevereCritical

Step-by-Step Breakdown

90-Day Mortality Reference (MELD-Na)

Score Range	Severity	~90-Day Mortality

Clinical note: This tool is for educational and reference purposes only. MELD-Na scores guide transplant allocation policy and are not a substitute for full clinical evaluation, multidisciplinary hepatology review, or transplant center protocols. Mortality estimates are population-based approximations. Always confirm results with laboratory-reported values and clinical judgment.

Summary

Enter serum bilirubin, creatinine, INR, and sodium to compute the MELD-Na score and estimate 90-day mortality risk in liver disease.

How it works

Enter the most recent serum bilirubin (mg/dL) from a metabolic panel.
Enter serum creatinine (mg/dL); enter 4.0 if the patient is on hemodialysis.
Enter the INR from a coagulation panel.
Enter serum sodium (mEq/L); the formula clamps values to the 125–137 range.
Click Calculate to compute both MELD and MELD-Na scores with a full breakdown.
Review the severity category, estimated mortality, and the step-by-step formula output.

Use cases

Estimate 90-day waitlist mortality for patients with cirrhosis or end-stage liver disease.
Determine UNOS organ allocation priority using the MELD-Na formula in use since 2016.
Identify patients whose serum hyponatremia significantly increases mortality risk beyond the classic MELD.
Track serial MELD-Na scores to monitor disease progression over hospitalizations.
Support TIPS (transjugular intrahepatic portosystemic shunt) patient selection.
Educate patients and families about liver disease severity with an objective, guideline-referenced score.
Compare MELD vs. MELD-Na to quantify the sodium penalty in hyponatremic patients.
Aid hepatology documentation with a reproducible, UNOS-compliant severity assessment.

Frequently Asked Questions

Last updated: 2026-06-14 · Reviewed by Nham Vu