BACKGROUND Acute cholangitis is caused by bacterial infection and has high morbidity and mortality risk. The grade of cholangitis can guide clinical treatment from single antibiotic treatment to biliary drainage. With the introduction of white blood cell (WBC) count, C-reactive protein (CRP), and total bilirubin (T-Bil) into the diagnostic criteria and severity grading for acute cholangitis, the diagnosis rate and grading have significantly improved. However, early risk stratification assessments are challenging in the emergency department. Therefore, we hope to find an ideal predictive biomarker for cholangitis grade. Presepsin is a promising biomarker for the early diagnosis, severity, and prognosis of acute bacterial infections. AIM To assess the grading value of presepsin in patients with acute cholangitis. METHODS This clinical study was conducted at the Beijing Friendship Hospital, a 2000-bed teaching hospital with approximately 200000 emergency admissions per year. In this prospective observational study, 336 patients with acute cholangitis meeting the Tokyo Guidelines 2018 diagnostic criteria in the emergency department from May 2019 to December 2020 were analyzed. WBC count, CRP, procalcitonin (PCT), presepsin, T-Bil, and blood culture results were collected. The values were compared using the Pearson.2 test, Fisher's exact test, or Mann-Whitney U test. The area under the receiver operating characteristic curve (AUC) of the value was examined using the Delong test. The correlations among the key research indicators were determined using Pearson correlation. RESULTS In total, 336 patients were examined, which included 107, 106, and 123 patients classified as having mild, moderate, and severe cholangitis, respectively. WBC count, CRP, PCT, presepsin, T-Bil, direct bilirubin, and sequential organ failure assessment scores of moderate and severe cholangitis patients were higher than those of mild cholangitis patients (P = 0.000). The AUC of presepsin in predicting moderate acute cholangitis was 0.728, which was higher than that of CRP (0.631, P = 0.043) and PCT (0.585, P = 0.002), and same as that of WBC count (0.746, P = 0.713) and T-Bil (0.686, P = 0.361). The AUC of presepsin in predicting severe acute cholangitis was 0.715, which was higher than that of WBC count (0.571, P = 0.008), CRP (0.590, P = 0.009), PCT (0.618, P = 0.024), and T-Bil (0.559, P = 0.006). The presepsin levels in the positive blood culture group were higher (2830.8pg/mLvs1987.8pg/ mL, P = 0.000), and the AUC of presepsin (0.688) proved that it was a good biomarker for predicting positive bacterial culture. CONCLUSION Presepsin can predict positive blood culture in patients with acute cholangitis. It is superior to WBC count, CRP, PCT, and T-Bil for the risk stratification of acute cholangitis.