Diagnostic Utility of Urinary Amylase in Acute Pancreatitis: A Systematic Review.

BACKGROUND: Diagnosis of acute pancreatitis (AP) is primarily based on serum amylase and lipase levels, which may normalize rapidly or remain within normal limits in early or late stages. Urinary amylase, with a longer detection window and easier sample collection, may offer a more sensitive diagnostic option, though evidence remains inconsistent. OBJECTIVE: This study aimed to systematically review published studies evaluating the diagnostic accuracy of urinary amylase in AP. METHODS: A comprehensive search was conducted across PubMed, Embase, Scopus, Web of Science, Cochrane Library, and Google Scholar for studies published from January 2010 to May 2025. Eligible studies included observational, prospective, or diagnostic accuracy designs assessing urinary amylase in clinically suspected or confirmed AP. Data on sensitivity, specificity, predictive values, and area under the curve (AUC) were extracted. Study quality was assessed using the QUADAS-2 tool. RESULTS: Thirteen studies (sample sizes 51-458) met the inclusion criteria, evaluating urinary amylase and urinary trypsinogen-2 in AP. Reported sensitivities ranged from 62.9% to 100% and specificities from 42.9% to 100%. Comparative analyses demonstrated that urinary biomarkers often performed as well as or better than serum amylase and lipase, with AUC values reaching up to 1.0. Several studies highlighted the high negative predictive value (up to 98.3%), suggesting strong utility for excluding AP. Urinary testing also provides practical advantages, including being non-invasive, rapid, and repeatable, which make it especially suitable for emergency and resource-limited settings. CONCLUSION: Urinary amylase and urinary trypsinogen-2 are sensitive, reliable, and clinically useful biomarkers for diagnosing AP. Their diagnostic performance equals or surpasses conventional serum markers, supporting their integration into diagnostic pathways as first-line or adjunctive tests. Standardized protocols and multicenter validation studies are recommended to optimize their clinical application.