Introduction: Parameters allowing regular evaluation of renal function in critically-ill patients such as serum creatinine and blood urea are not optimal. Sudden changes in glomerular filtration rate (GFR) are not followed by parallel changes in serum creatinine and are at risk of developing renal dysfunction. The aim of study: was to analyze the utility of serum cystatin C as a real-time biomarker of renal function in critically-ill patients with end stage liver disease (ESLD). Patients and Methods: serum creatinine, cystatin c and 24 hours creatinine clearance were determined daily to 300 patients (220 male and 80 female) critically-ill patients with ESLD. The serum levels of creatinine and cystatin c were correlated with the creatinine clearance daily. The diagnostic value of serum creatinine and cystatin c to identify GFR under 80 ml/min per 1.73 m2 was evaluated using receiver operating characteristic (ROC) curve analysis. Result: Thirty out of 300 patients (10 %) had serum creatinine above the upper limit of normal, while 85 out of 300 patients (28.3 %) had serum cystatin c above the upper limit of normal. Statistically the ability of serum cystatin c to identify a creatinine clearance rate 80 ml/min per 1.73 m2was better than that of serum creatinine (areas under the ROC curve: for cystatin c 0.925, and for creatinine0.613). Conclusion: serum cystatin c is an accurate easy and useful marker, better than serum creatinine to detect early renal dysfunction in real-time before acute renal injury in critically-ill patients.
