Objective:To evaluate the value of shock index and platelet count in early identification of grade 3 acute cholangitis.Methods:This study is a retrospective case-control study. A total of 750 patients who met the diagnostic criteria of acute cholangitis were treated in Beijing Friendship Hospital Affiliated to Capital Medical University from January 2018 to December 2020. They were divided into grade 1, grade 2 and grade 3 groups according to the 2018 Tokyo Guidelines. The age, gender, etiology, complications, Charlson comorbidity index (CCI), vital signs, blood routine indexes, C-reactive protein, lactic acid and consciousness of patients in each group were compared, and the effective indexes for differentiating grade 3 cholangitis were selected. Logistic regression and receiver operating characteristic curve (ROC) analysis were used to screen the indexes with high specificity and sensitivity for early identification of acute cholangitis.Results:There were significant differences in age, CCI score, incidence of acute cholecystitis, all-cause mortality, shock index, heart rate, systolic blood pressure, diastolic blood pressure, mean arterial pressure, respiration, lactic acid, white blood cell count, neutrophil count, lymphocyte count, granulocyte ratio, C-reactive protein, hematocrit, platelet count, thrombocytocrit and platelet distribution width among the three groups ( P<0.05). ROC curve analysis showed that platelet count and thrombocytocrit were more effective in predicting grade 3 cholangitis ( P<0.05). Logistic regression analysis showed that shock index and platelet were significantly correlated with grade 3 cholangitis ( P<0.05). For patients without unconsciousness, the area under curve (AUC) value of shock index alone was 0.621 for differentiating grade 3 cholangitis; The sensitivity was 47.6%, and the specificity was 71.3%. The AUC value of combined shock index and platelet for differentiating grade 3 cholangitis was 0.861, with a specificity of 95.6% and sensitivity of 71%. Conclusions:Shock index combined with platelet can be used as a good indicator for early differentiation of severe acute cholangitis without conscious disorder.