A direct test of pancreatic function that assesses both the endocrine and exocrine functions of the pancreas. A double-lumen tube is inserted into the patient’s gastrointestinal tract. One lumen samples the duodenal juices, the other removes gastric secretions. First secretin and then cholecystokinin are given to the patient intravenously; then the duodenal juices are analyzed to determine whether adequate levels of bicarbonate and trypsin are secreted.