The MELD score is a number between 6 and 40 that estimates how urgently a person with liver disease needs a liver transplant. It predicts the risk of dying from liver disease within the next 90 days, and it’s the primary tool used to rank patients on the national liver transplant waiting list. The higher the score, the sicker the patient and the more urgently they need a new liver.
How the MELD Score Works
MELD stands for Model for End-Stage Liver Disease. It’s a mathematical formula that uses results from routine blood tests to produce a single number reflecting how well (or poorly) the liver is functioning. The United Network for Organ Sharing (UNOS), which regulates organ transplantation in the United States, adopted the MELD score for transplant allocation in 2002. Before that, placement on the waiting list involved more subjective assessments that were prone to bias.
The system’s core purpose is straightforward: make sure the sickest patients get transplants first. Since its introduction, MELD has increased transplant rates for the most severely ill patients and reduced deaths on the waiting list, all without hurting survival after transplant.
What Goes Into the Calculation
The original MELD formula uses three lab values that together paint a picture of liver and kidney function plus blood clotting ability:
- Bilirubin: A waste product the liver normally clears from the blood. Rising levels signal the liver is falling behind.
- Creatinine: A marker of kidney function. Advanced liver disease often drags kidney function down with it.
- INR (International Normalized Ratio): Measures how quickly blood clots. The liver produces clotting proteins, so a high INR means the liver isn’t keeping up.
These three values are plugged into a logarithmic equation that weights each one differently. You don’t need to do the math yourself. Online calculators and your medical team handle it, and the score gets recalculated at regular intervals as your condition changes.
MELD-Na and the Role of Sodium
Researchers found that the original three-variable formula missed an important piece of the puzzle: serum sodium. Low sodium levels in patients with cirrhosis reflect a type of circulatory dysfunction where the body retains too much water relative to salt. The more severe the sodium drop, the worse the outlook.
Adding sodium to the formula created MELD-Na, which proved more accurate at predicting death than the original MELD alone. MELD-Na became the standard scoring system for transplant allocation, giving a better read on disease severity for patients whose original MELD score didn’t fully capture how sick they were.
MELD 3.0: The Latest Version
In 2023, the United States launched MELD 3.0, the newest version of the scoring system. It adds two more variables: sex and serum albumin (a protein made by the liver that drops as liver function worsens).
The sex adjustment corrects a longstanding problem. Women naturally have lower creatinine levels than men, which made the older formulas systematically underestimate how sick female patients were. Women with equally severe liver disease often received lower scores than men, pushing them further down the transplant list. MELD 3.0 explicitly accounts for this difference, reclassifying more women into higher priority categories and narrowing a gender gap in waitlist deaths that had persisted for years.
Albumin, meanwhile, adds another direct measure of how well the liver is producing essential proteins. Together, these changes give a more complete and equitable picture of a patient’s true condition.
What the Numbers Mean
MELD scores range from 6 to 40. A score of 6 means relatively stable liver function, while scores approaching 40 indicate an extremely high risk of death within three months without a transplant. The score applies to anyone age 12 and older with liver disease. Children under 12 are evaluated with a separate pediatric scoring system that accounts for growth and development factors specific to younger patients.
Generally, scores can be grouped into broad tiers:
- Below 10: Lower short-term mortality risk. These patients are on the list but are not prioritized for immediate transplant.
- 10 to 19: Moderate risk. Patients are monitored closely with regular recalculations.
- 20 to 29: High risk. The urgency for transplant increases significantly.
- 30 to 39: Very high risk. These patients are among the most critically ill on the waiting list.
- 40: The maximum score, representing the highest level of urgency.
These are general ranges, not hard cutoffs. The transplant team considers the full clinical picture alongside the score when making decisions.
Exception Points for Certain Conditions
Some liver conditions are life-threatening but don’t always push lab values high enough to generate a MELD score that reflects the true urgency. For these patients, the system grants “exception points” that raise their effective score on the transplant list. Conditions that may qualify include liver cancer (hepatocellular carcinoma), a blood clot in the liver’s main artery, certain lung complications caused by liver disease (hepatopulmonary syndrome and portopulmonary hypertension), cystic fibrosis, and several inherited metabolic disorders.
Exception points exist because the MELD formula, while powerful, is built around specific lab values that don’t capture every way liver disease can threaten a person’s life. A patient with early-stage liver cancer, for example, might have relatively preserved liver function on paper but faces a rapidly closing window for successful transplant.
How the Score Affects Your Place on the List
When a donor liver becomes available, it is offered first to the patients with the highest MELD scores within the local region, then expands to broader geographic areas. Blood type compatibility and body size also factor in, but the MELD score is the primary driver of who gets the offer.
Your score isn’t static. It gets recalculated at intervals that depend on its current level. Patients with higher scores are rechecked more frequently because their condition can change quickly. If your liver function improves (after treating an infection or stopping alcohol use, for example), your score can drop and your position on the list adjusts accordingly. If it worsens, your score rises and you move up.
The MELD score is also used outside of transplant decisions. Some doctors use it to gauge the severity of liver disease in patients who aren’t transplant candidates, helping guide treatment intensity and prognosis conversations. But its primary, most consequential role remains deciding who gets a new liver and when.