OBJECTIVE Early diagnosis of acute pancreatitis remains a challenge. A rapid dipstick screening test for acute pancreatitis has been developed. This prospective study was designed to evaluate the diagnostic value and time course of the rapid urinary trypsinogen-2 test strip in acute pancreatitis, with comparisons with serum amylase and serum lipase. METHODS A total of 165 patients with acute abdominal pain (67 with acute pancreatitis and 98 with other acute abdominal diseases) attending our emergency unit were included. All patients were tested with the urinary trypsinogen-2 test strip, and serum amylase and serum lipase concentrations were determined simultaneously. To measure the time course of the urinary trypsinogen-2 test, 32 patients with acute pancreatitis were tested with a urinary trypsinogen-2 test strip on days 1, 2, 3, and 4 after admission. RESULTS Using a cutoff level of 50 microg/L for urinary trypsinogen-2, the sensitivity, specificity, and accuracy of the urinary trypsinogen-2 test strip for recognition of acute pancreatitis were 89.6%, 85.7%, and 87.3%, respectively. The diagnostic accuracy rates of serum amylase and serum lipase were 88.5% and 93.3%, using cutoff values of 3 times the upper normal limits for serum amylase and serum lipase, respectively. All but one of the 17 patients with severe acute pancreatitis was detected by the test strip (sensitivity, 94.1%). The time-course study of the urinary trypsinogen-2 test strip revealed that the sensitivity on days 1, 2, 3, and 4 was 90.6%, 81.2%, 59.4%, and 50%, respectively. There was no significant difference in the sensitivity between urinary trypsinogen-2 and serum lipase; however, the sensitivity values of serum lipase were significantly higher than those of serum amylase from days 1 to 4. CONCLUSIONS The rapid urinary trypsinogen-2 test is a reliable and simple method for the early diagnosis of acute pancreatitis. A positive test identifies patients in need of further diagnostic measures. The urinary trypsinogen-2 test can be performed in health care units where laboratory testing facilities are not immediately available.