Medical AIMELD-Na end-stage liver disease calculator
MELD-Na adds serum sodium to the classic MELD model (bilirubin, INR, creatinine), capturing the prognostic weight of hyponatraemia in cirrhosis. It estimates 90-day mortality and was used by OPTN for liver allocation from 2016 until MELD 3.0 superseded it.
How to measure each input
- Total bilirubin
- Use total (not direct) serum bilirubin in mg/dL; the calculator converts umol/L by dividing by 17.1. Values below 1.0 are floored to 1.0 by the formula.
- INR
- International normalised ratio of the prothrombin time. Values below 1.0 are floored to 1.0. Direct oral anticoagulants distort the INR and make the score unreliable.
- Creatinine
- Serum creatinine in mg/dL (umol/L is divided by 88.4). It is floored at 1.0, capped at 4.0, and set to 4.0 if the patient had at least two dialysis sessions (or 24 hours of CVVHD) in the prior week.
- Sodium
- Serum sodium in mmol/L. Within the MELD-Na term it is bounded to the 125 to 137 range, so values outside that window are clamped before the calculation.
Interpretation
| Band | Meaning |
|---|---|
| <= 9, low risk | Approximately 1.9 percent estimated 3-month mortality in the classic MELD validation. Low priority for transplant listing on score alone. |
| 10 to 19, moderate risk | Roughly 6 percent estimated 3-month mortality at the lower end, rising through this band. Hepatology follow-up; reassess for transplant evaluation as the score climbs. |
| 20 to 29, high risk | Approximately 19.6 percent estimated 3-month mortality. Substantial waitlist priority; ensure transplant evaluation is under way and complications are managed. |
| 30 to 39, very high risk | Approximately 52.6 percent estimated 3-month mortality. Very high waitlist priority; intensive management and expedited transplant consideration. |
| 40, extreme risk | Around 71 percent or higher estimated 3-month mortality. The score is capped at 40 and carries the highest standard allocation priority. |
Pitfalls, exclusions and caveats
- MELD 3.0 has superseded MELD-Na for OPTN liver allocation (effective 2023). MELD 3.0 adds serum albumin and a female sex adjustment and changes coefficients, so MELD-Na should be read as historical or educational for allocation purposes.
- The score is invalid if INR is affected by anticoagulants (warfarin, direct oral anticoagulants) rather than by hepatic synthetic dysfunction.
- Creatinine is sensitive to non-hepatic factors: muscle mass, hydration, and intrinsic kidney disease all move the score independently of liver function.
- Laboratory method differences in INR and creatinine assays introduce real variability between centres, which is why the formula uses conservative floors and caps.
- MELD-Na predicts short-term mortality; it does not capture complications such as variceal bleeding, refractory ascites, or hepatocellular carcinoma, which may justify exception points.
MELD(i) = 0.957 x ln(creatinine) + 0.378 x ln(bilirubin) + 1.120 x ln(INR) + 0.643, then x 10 and round. Lab values < 1.0 set to 1.0; creatinine capped at 4.0 (or set to 4.0 if dialysed twice in the last week). If MELD > 11: MELD-Na = MELD + 1.32 x (137 - Na) - [0.033 x MELD x (137 - Na)], with Na bounded to 125 to 137.MELD was described by Kamath et al. (2001) and the sodium adjustment by Kim et al. (2008); allocation rules are set by OPTN/UNOS. This implementation is an educational tool and is not affiliated with those authors or organisations, and must not be used for actual organ allocation.
Frequently asked
How is MELD-Na different from MELD?
MELD-Na adds serum sodium to the classic MELD (bilirubin, INR, creatinine). Hyponatraemia is an independent marker of mortality in cirrhosis, so adding sodium improved prediction, especially at lower MELD scores. The sodium term is only applied when MELD is above 11.
Is MELD-Na still used for transplant allocation?
In the United States, OPTN moved to MELD 3.0 in 2023, which adds serum albumin and a female sex adjustment. MELD-Na is therefore best treated as historical or educational for allocation, though it remains a recognised prognostic score.
Why are bilirubin, INR, and creatinine floored at 1.0?
The formula uses natural logarithms, so values below 1.0 would produce negative contributions and could be exploited by minor lab variation. Flooring each at 1.0 keeps the score stable and reproducible across laboratories.
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