Beyond serum creatinine: which tools to evaluate renal function in cirrhotic patients?

In cirrhotic patients, a high serum creatinine value is an independent mortality factor. Similarly, it is predictive of renal insufficiency after liver transplantation. In these cases, chronic kidney disease is also an independent mortality factor. A relevant evaluation of glomerular filtration rate is crucial, particularly in cases of end-stage liver disease or liver transplantation, and is key for the decision to undertake dual liver-kidney transplantation. Serum creatinine or creatinine-based equations are the most used tools in clinical practice but they significantly overestimate renal function. Equilibrium inulin renal clearance remains the gold standard but is time consuming and expensive. Cystatin C and cystatin C-based equations are less influenced by muscle mass or bilirubin value, but their dosage is not standardized and they are expensive. Pharmacological models using exogenous markers, new kidney biomarkers, Doppler coupled with ultrasounds, and kidney histology could be interesting tools but their indications need to be specified.