MELD Score Calculator
The Model for End-Stage Liver Disease (MELD) score is a reliable measure of mortality risk in patients with end-stage liver disease. It is widely used to prioritize patients for liver transplantation. The MELD-Na score, which incorporates serum sodium, is a refinement that provides an even more accurate prediction of short-term mortality.
Understanding the MELD Score
The MELD score is a prognostic model 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 Eurotransplant for prioritizing patients on the liver transplant waiting list.
Components of the MELD Score
The original MELD score is calculated using three laboratory values:
- Total Bilirubin: A measure of liver's ability to process bile. Higher levels indicate more severe liver dysfunction.
- INR (International Normalized Ratio): A measure of how long it takes for blood to clot. The liver produces clotting factors, so a high INR suggests impaired liver function.
- Creatinine: A measure of kidney function. Kidney dysfunction is common in advanced liver disease (hepatorenal syndrome) and significantly impacts prognosis.
The MELD-Na score incorporates an additional factor:
- Serum Sodium: Low sodium levels (hyponatremia) are common in advanced liver disease and are associated with increased mortality, independent of the other MELD components.
How the MELD Score is Calculated
The MELD score is a logarithmic equation. Specific caps and minimums are applied to the lab values before calculation to ensure consistency and clinical relevance:
- Bilirubin, INR, Creatinine: Any value less than 1.0 is set to 1.0 for the calculation.
- Creatinine: The maximum value used for creatinine is 4.0 mg/dL. If a patient has received two or more dialysis treatments within the last 7 days or is on continuous renal replacement therapy (CRRT), their creatinine is automatically set to 4.0 mg/dL, regardless of its actual value.
- Sodium: For the MELD-Na calculation, sodium values are capped between 125 mEq/L (lower limit) and 137 mEq/L (upper limit). If a patient's sodium is below 125, 125 is used; if it's above 137, 137 is used.
The MELD score is always at least 6. The final MELD and MELD-Na scores are typically rounded to the nearest whole number.
Interpreting Your MELD Score
A higher MELD or MELD-Na score indicates more severe liver disease and a higher risk of mortality. This means patients with higher scores are generally prioritized for liver transplantation. The score helps clinicians and transplant centers make informed decisions about patient care and organ allocation.
Example: Let's calculate the MELD-Na score for a patient with:
- Total Bilirubin: 5.0 mg/dL
- INR: 2.5
- Creatinine: 2.0 mg/dL
- Serum Sodium: 130 mEq/L
- No Dialysis
Using the calculator with these values, the MELD score would be approximately 29, and the MELD-Na score would be approximately 32. This indicates severe liver disease.
It's important to remember that the MELD score is a tool for medical professionals and should be interpreted in the context of a patient's overall clinical condition. Always consult with a healthcare provider for diagnosis and treatment.