Clinical Utility and Optimal Sampling Timing of Urinary Trypsinogen-2 for Early Prediction of Post-endoscopic Retrograde Cholangiopancreatography Pancreatitis: A Prospective Observational Study

PURPOSE: Endoscopic retrograde cholangiopancreatography (ERCP) is essential for pancreatobiliary diseases but carries a risk of post-ERCP pancreatitis (PEP). Early prediction of PEP is crucial; thus, urinary trypsinogen-2 (UT2) is a potential biomarker, but its role and optimal measurement timing remain unclear. METHODS: This single-center prospective study enrolled consecutive patients undergoing their first ERCP at our institution between February 2022 and June 2024. Patients with choledochojejunostomy, biliary pancreatitis, or hemodialysis were excluded. The diagnostic performance of UT2 was evaluated immediately, 1 h, and 3 h after ERCP, and compared with serum amylase (AMY) measured 3 h after ERCP. RESULTS: Of 521 patients screened, 337 were analyzed (median age 74 years, 64% male). PEP occurred in 10% (mild 8.6%, moderate 1.2%, severe 0.3%). UT2 was positive prior to ERCP in 28.5% of patients and was more frequent among older patients and those with pancreatic cancer. UT2 sensitivity peaked at 1 h and remained stable thereafter. UT2 at 1 h showed higher sensitivity than AMY at 3 h (64.7% vs 52.9%) but lower specificity (64.7% vs 92.7%) and accuracy (64.7% vs 88.7%). In the subgroup analysis of patients with negative baseline UT2, specificity and accuracy were 87.1 and 83.8%, respectively, comparable to those of AMY (91.7% and 88.0%). CONCLUSION: Although the diagnostic performance of UT2 was lower than that of AMY, its performance plateaued at 1 h, suggesting that UT2 may facilitate earlier prediction of PEP.