How to Use the MELD Score Calculator
The MELD score calculator (Model for End-Stage Liver Disease) is a critical tool used by medical professionals to assess the severity of chronic liver disease. It is primarily used to prioritize patients for liver transplants. By entering standard laboratory values, this calculator provides a score between 6 and 40 that predicts the 3-month mortality risk for patients with cirrhosis.
To get an accurate result, you will need the following laboratory values from a recent blood draw:
- Bilirubin
- Measures the amount of bile pigment in the blood, indicating how well the liver is clearing waste.
- INR (International Normalized Ratio)
- Measures the blood's ability to clot, which is a key function of liver-produced proteins.
- Creatinine
- An indicator of kidney function, as kidney failure often accompanies advanced liver disease.
- Sodium
- Used in the MELD-Na formula to provide more accurate predictions for patients with low serum sodium levels (hyponatremia).
The MELD Score Formula
The MELD score is calculated using natural logarithms of laboratory results. The modern standard is the MELD-Na, which adjusts the initial MELD score based on serum sodium levels. The fundamental formula is:
MELD(i) = 10 * [0.957 * ln(Cr) + 0.378 * ln(Bili) + 1.120 * ln(INR) + 0.643]
Specific rules apply to ensure the score is standardized:
- If any value is less than 1.0, it is automatically rounded up to 1.0.
- If the patient has had dialysis twice within the last 7 days, the Creatinine value is set to 4.0 mg/dL.
- The maximum Creatinine value allowed in the formula is 4.0 mg/dL.
- Sodium levels are capped between 125 and 137 mEq/L.
MELD Score Interpretation
Understanding the score is vital for transplant planning. Higher scores indicate a higher urgency for a liver transplant. The following table represents the estimated 3-month mortality based on MELD score ranges:
| MELD Score | 3-Month Mortality |
|---|---|
| 40 or higher | 71.3% mortality |
| 30–39 | 52.6% mortality |
| 20–29 | 19.6% mortality |
| 10–19 | 6.0% mortality |
| 9 or lower | 1.9% mortality |
Calculation Example
Example Scenario: A patient presents with Bilirubin of 2.5 mg/dL, INR of 1.8, Creatinine of 1.2 mg/dL, and Sodium of 130 mEq/L. They are not on dialysis.
Step-by-step calculation:
- Determine MELD(i): 10 * [0.957 * ln(1.2) + 0.378 * ln(2.5) + 1.120 * ln(1.8) + 0.643]
- Calculation: 10 * [0.174 + 0.346 + 0.658 + 0.643] = 18.21. Round to 18.
- Calculate Sodium Adjustment: MELD + 1.32 * (137 – 130) – [0.033 * 18 * (137 – 130)]
- Adjustment: 18 + 9.24 – 4.158 = 23.08
- Final MELD-Na Score: 23
Common Questions
What is a "good" MELD score?
In the context of the MELD score calculator, lower is better. A score of 6 is the baseline for a healthy individual. As the score increases, the liver function is considered more compromised.
How often should the MELD score be recalculated?
Recalculation frequency depends on the score severity. Patients with a score over 25 may need labs every week, while those with scores below 10 may only need testing every year while on a transplant waitlist.
Does the MELD score apply to children?
No. For children under the age of 12, the PELD (Pediatric End-Stage Liver Disease) score is used instead, which accounts for factors like growth failure and age.