Serum and urinary biomarkers for predicting acute kidney injury after partial nephrectomy Abstract Purpose: The purpose of this study was to evaluate the ability of specific biomarkers to predict acute kidney injury (AKI) after partial nephrectomy.Methods: A prospective study of 89 patients undergoing partial nephrectomy was conducted in the First Affiliated Hospital of Fujian Medical University. The patients were divided into two groups according to AKI status: an AKI group and non-AKI group. Receiver operator characteristic (ROC) curves were generated and the areas under the curve (AUCs) were compared.Results: Twenty-eight subjects (31.5%) developed AKI while sixty-one subjects (68.5%) did not. Vascular clamping time in the AKI group was longer than that in the non-AKI group (29 ± 17 min vs. 24 ± 9 min, P = 0.042). Eight patients (28.6%) received blood infusion in the AKI group compared with five patients (8.2%) in the non-AKI group (P = 0.021). The area under ROC curve for AKI prediction was 0.792 [95% confidence interval (CI) 0.697 to 0.888, P < 0.000] for serum cystatin C 24 hours after surgery and 0.756 (95% CI 0.656 to 0.857, P < 0.000) for serum cystatin C 48 hours after surgery. Multivariate regression analysis showed transfusion [Hazard ratio (HR) 3.712, P = 0.044] and 24 hours serum cystatin C (HR 41.594, P = 0.001) correlated with AKI.Conclusions: Postoperative serum cystatin C may be an early predictor for AKI after partial nephrectomy. Transfusion may be an independent risk factor for AKI after partial nephrectomy Partial nephrectomy is considered the preferable treatment for small renal cell carcinoma tumors, resulting in equivalent oncological outcomes but better preservation of renal function and improved overall survival compared with radical nephrectomy [1,2]. Interruption of renal blood flow through temporary renal artery occlusion is widely carried out during partial nephrectomy. This maneuver may improve visibility, aid in hemostasis and allow for adequate closure of the parenchymal defect; however, this may also cause renal ischemia reperfusion injury, which may induce postoperative acute kidney injury (AKI) [3]. Many studies have demonstrated that impaired renal function may increase postoperative non-cancer associated mortality [4,5]. Current criteria for AKI diagnosis and classification depend highly on serum creatinine (SCr) changes [6]; however, many studies have indicated that SCr is not a sensitive biomarker for detection of early AKI [7]. Although early AKI diagnosis could trigger early initiation of supportive measures and novel therapeutic strategies [8], the diagnosis of AKI is often delayed until the SCr level increases.Several clinical indicators are presently used to predict AKI after cardiac surgery and renal disease, including serum or urinary cystatin C [9]. Serum β2 microglobulin may also be an early indicator for acute kidney ischemia (based on data from animal models) and urinary concentrations of β2 microglobulin are measured to evaluate percutaneous nephrolithotomyind...