Other kinds of lab tests are used to check for the specific type of pancreatic NETs.
The following tests and procedures may be used:
Fasting serum gastrin test: A test in which a blood sample is checked to measure the amount of gastrin in the blood. This test is done after the patient has had nothing to eat or drink for at least 8 hours. Conditions other than gastrinoma can cause an increase in the amount of gastrin in the blood.
Basal acid output test: A test to measure the amount of acid made by the stomach. The test is done after the patient has had nothing to eat or drink for at least 8 hours. A tube is inserted through the nose or throat, into the stomach. The stomach contents are removed and four samples of gastric acid are removed through the tube. These samples are used to find out the amount of gastric acid made during the test and the pH level of the gastric secretions.
Secretin stimulation test: If the basal acid output test result is not normal, a secretin stimulation test may be done. The tube is moved into the small intestine and samples are taken from the small intestine after a drug called secretin is injected. Secretin causes the small intestine to make acid. When there is a gastrinoma, the secretin causes an increase in how much gastric acid is made and the level of gastrin in the blood.
Somatostatin receptor scintigraphy: A type of radionuclide scan that may be used to find small pancreatic NETs. A small amount of radioactive octreotide (a hormone that attaches to tumors) is injected into a vein and travels through the blood. The radioactive octreotide attaches to the tumor and a special camera that detects radioactivity is used to show where the tumors are in the body. This procedure is also called octreotide scan and SRS.
Fasting serum glucose and insulin test: A test in which a blood sample is checked to measure the amounts of glucose (sugar) and insulin in the blood. The test is done after the patient has had nothing to eat or drink for at least 24 hours.