MELD-Na Calculator — Sodium-Adjusted MELD for Liver Disease

How to Use This Calculator

1. Enter bilirubin, creatinine, INR, and serum sodium.
2. Select dialysis status if applicable.
3. MELD-Na and standard MELD display with the sodium adjustment contribution.
4. Use the vs MELD 3.0 tab to compare with the current UNOS allocation score.

Formula

Example

Frequently Asked Questions

• What is MELD-Na and how is it calculated? ▼
  MELD-Na is a sodium-adjusted version of the MELD score, developed to improve mortality prediction in cirrhotic patients by incorporating hyponatremia — a complication of portal hypertension that is strongly associated with poor outcomes independent of the standard MELD variables. The MELD-Na formula adds a sodium-dependent adjustment term to the standard MELD score: MELD-Na = MELD + 1.32 × (137 − Na) − [0.033 × MELD × (137 − Na)]. Serum sodium is capped between 125 and 137 mEq/L in the formula — values above 137 are set to 137 (no adjustment), and values below 125 are set to 125 (to prevent excessively high adjustments). When sodium is 137 mEq/L (the upper cap), MELD-Na equals standard MELD exactly. When sodium is 125 mEq/L, the adjustment adds the maximum penalty. The formula was derived from survival analyses showing that for any given MELD score, lower serum sodium predicted significantly higher 90-day waitlist mortality, and that adding sodium improved the model's discriminative ability. MELD-Na was officially adopted by UNOS for liver transplant allocation in January 2016, replacing standard MELD.
• Why was sodium added to the MELD score? ▼
  Serum sodium was added to MELD because hyponatremia is a powerful independent predictor of mortality in cirrhosis that the original MELD formula failed to capture. Hyponatremia in cirrhosis is primarily dilutional — caused by non-osmotic secretion of arginine vasopressin (ADH) triggered by reduced effective arterial blood volume from splanchnic vasodilatation and portal hypertension. This leads to free water retention and progressive hyponatraemia despite total body sodium overload. The pathophysiological significance of hyponatraemia in cirrhosis extends beyond its marker status: low sodium directly contributes to cerebral osmotic stress and is one of the key mechanisms driving hepatic encephalopathy in cirrhotic patients. Multiple cohort studies demonstrated that for identical MELD scores, patients with sodium below 130 mEq/L had substantially higher 3-month waitlist mortality than those with normal sodium. A landmark study by Kim et al. (2008, NEJM) showed that adding sodium to MELD improved the c-statistic for 90-day waitlist mortality from 0.87 to 0.90. These data provided the regulatory justification for UNOS to mandate MELD-Na as the allocation standard.
• How does MELD-Na compare to MELD 3.0? ▼
  MELD-Na and MELD 3.0 share the same foundation but differ in scope and purpose. MELD-Na was introduced in 2016 to address hyponatremia, improving prediction over standard MELD by adding a single adjustment term for sodium. MELD 3.0, introduced in 2022, built upon MELD-Na's framework but specifically targeted a second important limitation: sex-based inequity in transplant access. Studies found that women were consistently waitlisted and transplanted at higher MELD-Na scores than men with equivalent waitlist mortality, primarily because creatinine systematically underestimates renal dysfunction in women (lower muscle mass = lower baseline creatinine). MELD 3.0 addresses this by: using a different creatinine coefficient; incorporating serum albumin as a synthetic function marker; retaining sodium; and adding a fixed 1.33-point bonus for female sex. In validation studies, MELD 3.0 reduced the sex-based gap in transplant access without reducing overall predictive accuracy. MELD-Na remains clinically familiar and useful as a reference, but MELD 3.0 is now the operative UNOS allocation tool. For clinical practice outside of US transplant allocation, MELD-Na and MELD 3.0 are interchangeable as prognostic tools.
• When is sodium capped in the MELD-Na formula? ▼
  Serum sodium is capped at both ends of the MELD-Na formula for mathematical and clinical reasons. The upper cap at 137 mEq/L means that any sodium value at or above 137 contributes zero adjustment to MELD-Na — the score equals standard MELD exactly. This prevents patients with high-normal or hypernatraemic sodium from receiving an artificially reduced MELD-Na, which could happen without the cap because the formula subtracts (137 − Na). The lower cap at 125 mEq/L prevents disproportionate score inflation in patients with profound hyponatraemia (sodium <125 mEq/L) that could disrupt allocation equity — at 125, patients already receive the maximum sodium-related adjustment. In practice, the clinical range most affected by the MELD-Na adjustment is sodium 125–136 mEq/L, where each 1 mEq/L decrease in sodium adds approximately 1–2 points to the score (the exact magnitude depends on the base MELD due to the interaction term). Clinicians should note that sodium must be interpreted in the clinical context: patients receiving salt-free albumin infusions, diuretics, or terlipressin may have rapidly changing sodium values, and a single measurement may not reflect steady-state sodium status.
• How accurate is MELD-Na for predicting transplant outcomes? ▼
  MELD-Na demonstrates good but imperfect accuracy for predicting waitlist mortality — the outcome it was primarily designed for. In the original UNOS validation dataset used to justify adoption, the c-statistic (AUROC) for 90-day waitlist mortality improved from 0.87 (standard MELD) to 0.90 (MELD-Na). This improvement is statistically significant and clinically meaningful at the population level, translating into more equitable organ allocation. However, for individual patients, a c-statistic of 0.90 means that in approximately 10% of paired comparisons, MELD-Na incorrectly ranks the higher-mortality patient lower. The score performs best for mortality prediction in the 90-day window; accuracy degrades for longer time horizons. MELD-Na also does not capture several important prognostic factors including hepatic encephalopathy severity, nutritional status (partially addressed in MELD 3.0 via albumin), malignancy burden in HCC patients, portal vein thrombosis, sarcopenia, and frailty. Frailty — measured by the Liver Frailty Index or 6-minute walk test — has been shown to add significant prognostic information beyond MELD-Na alone, and is increasingly incorporated into transplant centre-specific listing criteria.

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