Gastrin
The Test
How is it used?
A gastrin test may also be ordered to monitor for recurrence following the surgical removal of a gastrinoma.
Sometimes a gastrin stimulation test may be ordered if a gastrin result is not significantly elevated, but the doctor still suspects that the patient’s symptoms are due to a gastrinoma. This procedure involves collecting a baseline gastrin sample, giving the patient a chemical (typically the hormone secretin) to stimulate gastrin production, and then drawing additional gastrin samples at timed intervals.
A measurement of gastric acid level (pH) may sometimes be ordered along with or following a gastrin test to help diagnose ZE syndrome.
When is it ordered?
When you have had a gastrin-producing tumor removed, a gastrin test may be ordered periodically as a screening test to monitor for recurrence.
What does the test result mean?
Gastrin levels can increase with age and with prolonged use of medications such as antacids and proton pump inhibitors that neutralize or inhibit the production of stomach acid. They will also typically be elevated in patients who are not fasting.
Greatly increased levels of gastrin in symptomatic patients and concentrations of gastrin that increase significantly during a gastrin stimulation test indicate the likelihood that a person has ZE syndrome and one or more gastrinomas. Imaging tests are typically ordered as a follow-up to high gastrin concentrations to locate the gastrinoma(s). The quantity of gastrin produced is not related to either the tumor size or to the number of tumors. Even tiny tumors can produce large amounts of gastrin.
Gastrin levels that were initially low after the surgical removal of a gastrinoma and then increase may signal a recurrence of the tumor. Concentrations that do not decrease after treatment may indicate that the treatment has not been fully effective.
Is there anything else I should know?
It is important to note that most stomach ulcers are not due to gastrinomas. They are commonly associated with Helicobacter pylori infections and sometimes with the use of NSAIDs (nonsteroidal anti-inflammatory medicines) such as ibuprofen.
Increases in gastrin concentration with age may reflect a general decrease in the ability to produce stomach acid.
