Isoamylase determinations in patients undergoing endoscopic retrograde cholangiopancreatography.

The isoamylase profile in 24 patients undergoing ERCP were prospectively studied. Serum samples were obtained prior to and 4 hours following ERCP. All patients had the bile duct successfully visualized and in all but one patient the pancreatic duct was seen. Twenty-two of the 24 patients had a rise in the total serum amylase following ERCP. Most often this was from pancreatic sources, but two patients had a substantial rise in the salivary isoamylase. No patient developed clinical signs of acute pancreatitis. The patients in whom ductal pathology was found had a significant rise in pancreatic isoamylase following ERCP. Patients with normal pancreatic ducts did not show a significant rise in the pancreatic isoamylase. Patients who were hyperamylasemic prior to ERCP had a statistically significant post-ERCP rise in pancreatic isoamylase. In contrast, those who were normoamylasemic had no significant change in their pancreatic isoamylase level following the procedure. Development of hyperamylasemia is an expected sequela of ERCP, most often is due to pancreatic sources, and is rarely of clinical significance.