Pancreatic function tests - Investigations and procedures

Pancreatic function tests

Exocrine function

Serum amylase is a marker for pancreatic damage. A rise of more than 4 times normal with suggestive clinical features is diagnostic of acute pancreatitis, although lesser rises may occur due to other causes, e.g. mesenteric infarction and acute cholecystitis. A normal amylase level does not exclude acute pancreatitis. Serum lipase is also a marker for pancreatic damage.

Steatorrhea which is thought to be caused by chronic pancreatitis may be investigated using faecal fat estimation and/or a breath test to compare the absorption of a radiolabelled fatty acid versus a radiolabelled triglyceride. If the fatty acid is absorbed normally but the more complex triglyceride is not, then the steatorrhea is caused by pancreatic disease.

Other tests to assess the exocrine function, such as measuring the levels of enzymes in the duodenum after a food challenge, are available but not commonly performed.

Endocrine function

Chronic pancreatitis may lead to secondary diabetes mellitus. Tests for endocrine function in this context are not required.

Endocrine tests may be needed in the diagnosis of islet cell tumours. Pancreatic polypeptide is raised in all of these types of tumour.