MELD-Na Score

Q: How does hyponatremia change the MELD-Na score?

Hyponatremia raises the score. The formula adds 1.32 times the difference between 137 mmol/L and the measured sodium, with a small interaction term, so the further sodium falls below 137 the higher the result. Sodium below 125 is bounded at 125 before calculation. This reflects the observation that hyponatremia worsens prognosis in cirrhosis.

Q: Is MELD-Na still used for U.S. transplant allocation?

MELD-Na was adopted by UNOS because adding serum sodium improved mortality prediction compared with MELD alone, particularly in patients with hyponatremia. U.S. liver allocation transitioned to the MELD 3.0 model in July 2023, which incorporates albumin, sex, and updated coefficients, so MELD-Na is no longer the allocation score but remains a validated prognostic estimate.

Q: Why does a high sodium not improve the score?

Sodium is clamped to a maximum of 137 mmol/L, so the model does not reward supra-normal sodium; a value above 137 is treated the same as exactly 137. The score was built to capture the prognostic penalty of hyponatremia in advanced liver disease, not any potential benefit of higher sodium.

Model for End-stage Liver Disease Sodium (MELD-Na) score for predicting 3-month mortality in advanced liver disease.

Gastroenterology GastroenterologyEvidence-BasedUpdated 2026-07

Clinical decision-support tool for qualified healthcare professionals. Results are not a diagnosis and should not replace professional clinical judgment.

Clinical Notes

MELD-Na improves mortality prediction compared with MELD alone and is used for liver transplant allocation.

Calculator Information

Specialty

Gastroenterology

📋 Reference Ranges

Reference ranges for this calculator
Classification	Range
Low Risk	<10
Moderate Risk	10–19
High Risk	20–29
Very High Risk	30–39
Extremely High Risk	≥40

What This Calculator Measures

Calculates the MELD-Na score, which adds serum sodium to the MELD model to improve 3-month mortality prediction in advanced liver disease. MELD-Na is a widely used prognostic model for transplant waitlist mortality; U.S. liver allocation transitioned to the MELD 3.0 model in July 2023.

How to Use

Enter the most recent serum bilirubin, creatinine, INR, and sodium.
Indicate whether the patient has been on dialysis at least twice in the past week (creatinine is set to 4 mg/dL).
Serum sodium is clamped between 125 and 137 mmol/L by the model before calculation.
Review the score against the same mortality-risk bands used for MELD.

How the Calculation Works

MELD-Na = MELD + 1.32 x (137 - sodium) - [0.033 x MELD x (137 - sodium)], where MELD is the standard MELD score and sodium is in mmol/L. Sodium is bounded to 125-137 mmol/L before the calculation, and the result is rounded to the nearest integer.

Variables Explained

Serum Bilirubin

Serum bilirubin in mg/dL, entered into the MELD component with a floor of 1.0.

Serum Creatinine

Serum creatinine in mg/dL; floored at 1.0 and capped at 4.0, or set to 4.0 when on dialysis.

INR

International normalized ratio, entered into the MELD component with a floor of 1.0.

Serum Sodium

Serum sodium in mmol/L, bounded to 125-137 for the MELD-Na correction term.

Common error: Sodium values outside 125-137 mmol/L are clamped to those limits.

Dialysis at least twice in the last week?

Yes forces the creatinine term to 4.0 within the MELD component.

Interpretation Guide

MELD-Na <10 indicates low 3-month mortality risk; 10–19 moderate; 20–29 high; 30–39 very high; ≥40 extremely high risk. Sodium below 137 mmol/L raises the score because hyponatremia worsens prognosis.

Clinical Significance

MELD-Na was adopted by UNOS for liver allocation because adding serum sodium improves mortality prediction compared with MELD alone, particularly in patients with hyponatremia. U.S. liver allocation transitioned to the MELD 3.0 model in July 2023.

When It Is Useful

Transplant waitlist risk assessment in cirrhosis
Prognosis in cirrhosis with hyponatremia
Serial severity monitoring in decompensated liver disease

When It Is Not Useful

Acute liver failure, which is not modeled by MELD-Na
Pediatric patients (PELD-based allocation applies)
When serum sodium is unreliable, such as with recent aggressive diuresis or hypotonic fluid administration
As a replacement for clinical assessment of ascites and encephalopathy

Common Mistakes

Expecting a sodium above 137 mmol/L to reduce the score, since sodium is bounded to the 125-137 range before calculation and values above 137 change nothing.
Calculating the score immediately after aggressive diuresis or hypotonic fluid administration, when the measured sodium has not reached a steady state and can bias the result.
Applying the sodium adjustment to a MELD that was not calculated with the standard floors, creatinine cap, and dialysis rule, which produces a MELD-Na that does not match the published model.

Limitations

Sodium is clamped to a maximum of 137 mmol/L, so the score does not reward supra-normal sodium.
Non-hepatic causes of hyponatremia (e.g., SIADH, diuretics) can bias the score.
Retains the creatinine/INR caveats of the underlying MELD model.

Worked Example

A 60-year-old woman with cirrhosis and ascites is listed for transplant. Bilirubin is 2.5 mg/dL, creatinine 1.2 mg/dL, INR 1.5, sodium 130 mmol/L, and she is not on dialysis.

Inputs:

bilirubin: 2.5

creatinine: 1.2

inr: 1.5

sodium: 130

dialysis: no

Expected Result: MELD ≈ 16; MELD-Na = 16 + 1.32×(137−130) − 0.033×16×(137−130) ≈ 22 — high 3-month mortality risk (band 20–29).

Evidence & References

Source:: Original MELD-Na Description / UNOS
Content updated:: 2026-08

Kim WR, et al. N Engl J Med. 2008;359:1018-1026.

References

Kim WR, et al. Hyponatremia and mortality among patients on the liver-transplant waiting list. N Engl J Med. 2008;359:1018-1026. (Original model)

Frequently Asked Questions

How does hyponatremia change the MELD-Na score?

Hyponatremia raises the score. The formula adds 1.32 times the difference between 137 mmol/L and the measured sodium, with a small interaction term, so the further sodium falls below 137 the higher the result. Sodium below 125 is bounded at 125 before calculation. This reflects the observation that hyponatremia worsens prognosis in cirrhosis.

Is MELD-Na still used for U.S. transplant allocation?

MELD-Na was adopted by UNOS because adding serum sodium improved mortality prediction compared with MELD alone, particularly in patients with hyponatremia. U.S. liver allocation transitioned to the MELD 3.0 model in July 2023, which incorporates albumin, sex, and updated coefficients, so MELD-Na is no longer the allocation score but remains a validated prognostic estimate.

Why does a high sodium not improve the score?

Sodium is clamped to a maximum of 137 mmol/L, so the model does not reward supra-normal sodium; a value above 137 is treated the same as exactly 137. The score was built to capture the prognostic penalty of hyponatremia in advanced liver disease, not any potential benefit of higher sodium.

Disclaimer: This calculator is intended for educational and clinical decision support purposes only. MELD-Na is one component of transplant evaluation; allocation decisions follow current institutional and UNOS/OPTN policy (MELD 3.0 in the United States).