MELD Score Calculator
Use this calculator to estimate the Model for End-Stage Liver Disease (MELD) score, which is used to assess the severity of chronic liver disease and prioritize patients for liver transplantation.
Understanding the MELD Score
The Model for End-Stage Liver Disease (MELD) score is a reliable numerical scale used to assess the severity of chronic liver disease. It was initially developed to predict survival in patients undergoing transjugular intrahepatic portosystemic shunt (TIPS) procedures but has since been adopted by the United Network for Organ Sharing (UNOS) and Organ Procurement and Transplantation Network (OPTN) to prioritize adult patients for liver transplantation.
Why is the MELD Score Important?
The MELD score helps ensure that the sickest patients receive liver transplants first. A higher MELD score indicates more severe liver disease and a higher risk of death within three months without a transplant. The score ranges from 6 (least severe) to 40 (most severe).
Components of the MELD Score Calculation
The MELD score is calculated using four key laboratory values:
- Serum Bilirubin (mg/dL): Measures how well the liver is clearing bilirubin, a waste product from red blood cell breakdown. High levels indicate impaired liver function.
- INR (International Normalized Ratio): Measures the liver's ability to produce clotting factors. A high INR indicates poor liver function and increased bleeding risk.
- Serum Creatinine (mg/dL): Measures kidney function. Liver disease can affect kidney function, and elevated creatinine levels are a poor prognostic sign.
- Serum Sodium (mEq/L): (Used in MELD-Na) Reflects the body's fluid balance and is an independent predictor of mortality in liver disease.
How the MELD Score is Calculated (MELD-Na Formula)
The MELD score calculation involves a logarithmic formula and specific caps and minimums for each variable to ensure fairness and accuracy. The most commonly used version, MELD-Na, incorporates serum sodium.
Calculation Steps:
- Adjust Input Values:
- Bilirubin: Minimum value is 1.0 mg/dL. If your input is less than 1.0, it will be treated as 1.0.
- INR: Minimum value is 1.0. If your input is less than 1.0, it will be treated as 1.0.
- Creatinine: Maximum value is 4.0 mg/dL. If your input is greater than 4.0, it will be treated as 4.0. If the patient has been on dialysis (at least two treatments within the last 7 days), creatinine is automatically set to 4.0 mg/dL, regardless of the actual value.
- Sodium: Values are capped between 125 mEq/L and 137 mEq/L. If your input is below 125, it will be treated as 125. If it's above 137, it will be treated as 137.
- Calculate Base MELD Score:
MELD = 3.78 * ln(serum bilirubin) + 11.2 * ln(INR) + 9.57 * ln(serum creatinine) + 6.43
Where 'ln' is the natural logarithm.
- Adjust for Sodium (MELD-Na):
MELD-Na = MELD + 1.32 * (137 - Na) - [0.033 * MELD * (137 - Na)]
- Round to Nearest Whole Number: The final MELD-Na score is rounded to the nearest integer.
Example Calculation
Let's calculate the MELD-Na score for a patient with the following lab values:
- Serum Bilirubin: 2.5 mg/dL
- INR: 1.8
- Serum Creatinine: 1.5 mg/dL
- Serum Sodium: 130 mEq/L
- Dialysis Status: No
- Adjusted Values:
- Bilirubin: 2.5 (no change)
- INR: 1.8 (no change)
- Creatinine: 1.5 (no change, not on dialysis, below 4.0)
- Sodium: 130 (no change, between 125 and 137)
- Base MELD Calculation:
- ln(2.5) ≈ 0.916
- ln(1.8) ≈ 0.588
- ln(1.5) ≈ 0.405
MELD = (3.78 * 0.916) + (11.2 * 0.588) + (9.57 * 0.405) + 6.43
MELD = 3.46488 + 6.5856 + 3.87585 + 6.43 ≈ 20.356
- MELD-Na Adjustment:
137 - Na = 137 - 130 = 7
Adjustment = 1.32 * 7 - (0.033 * 20.356 * 7)
Adjustment = 9.24 - (0.033 * 142.492)
Adjustment = 9.24 - 4.6929 ≈ 4.547
- Final MELD-Na Score:
MELD-Na = 20.356 + 4.547 = 24.903
Rounded to the nearest whole number, the MELD-Na score is 25.
This calculator provides an estimate based on the standard MELD-Na formula. Always consult with a healthcare professional for medical advice and interpretation of MELD scores.
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function calculateMELD() {
var serumBilirubinInput = document.getElementById("serumBilirubin").value;
var inrValueInput = document.getElementById("inrValue").value;
var serumCreatinineInput = document.getElementById("serumCreatinine").value;
var serumSodiumInput = document.getElementById("serumSodium").value;
var dialysisStatus = document.getElementById("dialysisStatus").checked;
var resultDiv = document.getElementById("meldResult");
// Validate inputs
if (isNaN(serumBilirubinInput) || serumBilirubinInput === "" ||
isNaN(inrValueInput) || inrValueInput === "" ||
isNaN(serumCreatinineInput) || serumCreatinineInput === "" ||
isNaN(serumSodiumInput) || serumSodiumInput === "") {
resultDiv.innerHTML = "Please enter valid numerical values for all fields.";
return;
}
var bilirubin = parseFloat(serumBilirubinInput);
var inr = parseFloat(inrValueInput);
var creatinine = parseFloat(serumCreatinineInput);
var sodium = parseFloat(serumSodiumInput);
// Apply MELD rules for caps and minimums
bilirubin = Math.max(1.0, bilirubin);
inr = Math.max(1.0, inr);
if (dialysisStatus) {
creatinine = 4.0; // If on dialysis, creatinine is automatically 4.0
} else {
creatinine = Math.min(4.0, creatinine); // Otherwise, cap at 4.0
}
sodium = Math.min(137, Math.max(125, sodium)); // Cap sodium between 125 and 137
// Calculate Base MELD Score
var baseMELD = (3.78 * Math.log(bilirubin)) +
(11.2 * Math.log(inr)) +
(9.57 * Math.log(creatinine)) +
6.43;
// Calculate MELD-Na Adjustment
var sodiumAdjustment = (1.32 * (137 – sodium)) – (0.033 * baseMELD * (137 – sodium));
// Final MELD-Na Score
var finalMELD = baseMELD + sodiumAdjustment;
// Round to the nearest whole number
finalMELD = Math.round(finalMELD);
resultDiv.innerHTML = "Your estimated MELD-Na Score is:
" + finalMELD + "";
}