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MELD Score and INR

The model for end-stage liver disease (MELD) score attempts to objectively assesses the severity of chronic liver disease and prioritize liver transplants. The MELD formula is:

MELD = 3.78×ln[serum bilirubin (mg/dL)] + 11.2×ln[INR] + 9.57×ln[serum creatinine (mg/dL)] + 6.43; where ln = natural log.
MELD score is used to assess 3-month mortality: <9 = 1.9%; 10–19 = 6%; 20–29 = 19.6%; 30–39 = 52.6%; 40 and above = 71.3% mortality

As you can see, the MELD score relies heavily on INR, and there is concern that because the INR is based on thromboplastin ISI values computed from vitamin K antagonist (VKA) cilabrators, it may vary by local thromboplastin and coagulometer choices. There is a recommendation to compute liver disease specimen-based thromboplastin ISIs: Lee HJ, Kim JE, Lee HY, et al. Significance of local international sensitivity index systems for monitoring warfarin and liver function. Am J Clin Pathol 2014;141: 542–50, and Lee JH, Kweon OJ, Lee MK, et al. Clinical usefulness of international normalized ratio calibration of prothrombin time in patients with chronic liver disease. Int J Hematol 2015;102:163–9.

If you support a transplant service, have you made any modifications to your INR computations to normalize MELD values? Do you support the concept of a separately validated thromboplastin for MELD computation? What other approaches could be used to normalize the MELD value?

Comments (1)
Screening Assays
Apr 22, 2016 11:33pm

Hi George.

Hi George.
I am working in a cardiac center where we have been releasing PT/INR reports using Thromborel S reagent with a usual ISI value of 0.9. Last year, a liver transplant unit also started functioning in our center. They have performed many transplants and as yet have not commented on the PT reports released for our side using the same reagent . They are using the same to calculate MELD and so far appear fine with our reports. Guess more studies are needed to actually verify the INR difference in patients on warfarin vis a vis chronic liver disease patients.Thanks. Dr Siddhartha

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