BackgroundLipocalin2 (LCN2) is being increasingly used to diagnose and predict severe bacterial infection. We aimed to evaluate the predictive value of serum lipocalin 2 for severity grading of acute cholangitis (AC) on patient admission. MethodsA total of 108 patients were enrolled in this study. Blood samples were obtained at admission. Receiver operating characteristic (ROC) curves were built to assess the abilities of LCN2 levels to predict moderate/severe (vs. mild) or severe (vs. mild/moderate) AC with traditional markers of inflammation such as white blood cell (WBC) count, C-reactive protein (CRP), procalcitonin (PCT) and neutrophil-to-lymphocyte ratio (NLR). The correlations among the key research indicators were determined using spearman’s test. Multivariate analysis was conducted to identify the risk factors for severe AC. ResultsThe levels of LCN2 on admission increased significantly with the severity of AC. By analysis of ROC curve of biomarkers for differentiating patients with moderate to severe AC (versus mild AC), the AUC for LCN2 (0.925) was significantly greater than that for other inflammatory markers, and the optimal cut-off value of LCN2 was 262.2 ng/mL, with a sensitivity of 90.8% and specificity of 81.4%. In addition, the AUC for LCN2 (0.912) for severe acute cholangitis was also significantly greater than that for other inflammatory markers, and the optimal cut-off value of LCN2 was 325.7 ng/mL. The sensitivity and specificity were 86.1% and 83.3%, respectively. Furthermore, LCN2 the closest relationships were found between LCN2 and PCT (r = 0.8054, P < 0.001) through Spearman’s test. Multivariate analysis showed that LCN2 was the only risk factor predicting severe AC (P < 0.05). ConclusionSerum LCN2 concentration on patient admission could better predict severe acute cholangitis than WBC, CRP, PCT and NLR. Serum LCN2 may become a potential biomarker in the risk stratification of acute cholangitis and in indicating the time of biliary drainage.