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?