Which variables are used to calculate the MELD score?

The MELD (Model for End-stage Liver Disease) score is a clinical tool used to assess the severity of liver disease and prioritize candidates for liver transplantation. The components used to calculate the MELD score are creatinine, bilirubin, INR (International Normalized Ratio), and for patients undergoing dialysis, an adjustment is made.

Creatinine levels indicate kidney function, which is important as renal function can be significantly affected in liver disease. Bilirubin levels reflect bilirubin metabolism and liver function; elevated levels suggest a degree of liver dysfunction. INR is a measure of blood coagulation and reflects synthetic liver function; it indicates how well the liver is producing clotting factors.

The specific use of dialysis as a component serves to include patients who are receiving renal replacement therapy, which significantly affects the interpretation of creatinine levels in the context of liver disease.

Thus, the correct answer incorporates all the necessary components that relate directly to liver and kidney function, making it the proper criteria for calculating the MELD score.