MELD Calculator (Model for End-Stage Liver Disease)

The standard MELD score utilizes a logarithmic formula based on three routine blood tests: serum bilirubin (evaluating liver function), serum creatinine (evaluating kidney function), and the International Normalized Ratio or INR (evaluating blood clotting). The base formula calculates: MELDScore = 10 * ((0.957 * ln(Creatinine)) + (0.378 * ln(Bilirubin)) + (1.12 * ln(INR))) + 6.43. For patients undergoing dialysis, creatinine is automatically set to a standard cap. Additionally, the modern MELD-Na variant adjusts this baseline score by incorporating serum sodium levels, recognizing that hyponatremia is a strong independent predictor of mortality in end-stage liver disease.

Consider a patient with the following laboratory values: Serum Bilirubin = 3.2 mg/dL, Serum Creatinine = 1.4 mg/dL, INR = 1.8, and Serum Sodium = 130 mEq/L. First, we take the natural logarithms of the lab values: ln(1.4) = 0.336, ln(3.2) = 1.163, and ln(1.8) = 0.588. Multiplying these by their respective coefficients gives: (0.957 * 0.336) + (0.378 * 1.163) + (1.12 * 0.588) = 0.322 + 0.440 + 0.659 = 1.421. Multiplying this sum by 10 and adding 6.43 yields a base MELD score of approximately 20.64 (rounded to 21). Next, incorporating the sodium level of 130 mEq/L into the MELD-Na secondary equation adjusts the final score upward to account for hyponatremia, resulting in a MELD-Na score of roughly 24.

Always input laboratory values that were measured within the same timeframe, as fluctuations in hydration and kidney function can rapidly shift the score. Ensure that any creatinine values for patients receiving regular hemodialysis are handled according to standard transplant guidelines. Remember that this calculator is designed as a supportive decision-making tool for medical professionals and should not replace clinical judgment or official transplant center evaluations.