BACKGROUND/AIMS: The duodenal intubation test (duodenal secretin test; DST) is now considered the 'gold standard' test of exocrine pancreatic function in detecting exocrine pancreatic dysfunction in patients with chronic pancreatitis. However, the DST has not been widely used, because it is time-consuming, invasive, and labor-intensive. On the other hand, intraductal secretin test (IDST) with endoscopic retrograde cannulation of the main pancreatic duct has been showed similar diagnostic efficiency compared with DST. We assessed the clinical usefulness of IDST and investigated parameters for assessing impaired pancreatic function of IDST. METHODS: Pure pancreatic juices were collected from 12 patients with chronic pancreatitis by endoscopic cannulation after a bolus intravenous injection of secretin 100 U, for 15min in three 5-min intervals. Five parameters of IDST were measured, and the sensitivity, specificity, and accuracy of IDST evaluated compared with ERP. RESULTS: When we regarded mean-1.5 SD as the lower limits of IDST, the diagnostic sensitivity, specificity, and accuracy of five parameters to detect chronic pancreatitis were 91.7-100%, 75-87.5%, and 85-90%, respectively. Among five parameters, pancreatic juice secretory volume, bicarbonate concentration, and amylase output showed the highest diagnostic accuracy, followed by lipase output and bicarbonate output. A 10-min collection showed as much information as a 15-min collection. CONCLUSIONS: 10-min intraductal secretin test is useful as the conventional exocrine pancreatic function test in detecting exocrine pancreatic dysfunction in patients with chronic pancreatitis and the most discriminatory parameters are pancreatic juice secretory volume, bicarbonate concentration, and amylase output.