A gastrin test measures the level of the hormone gastrin in the blood. Gastrin is produced by cells, called G cells, in the stomach lining. When food enters the stomach, G cells trigger the release of gastrin in the blood. As blood levels of gastrin rise, the stomach releases acid (gastric acid) that helps break down and digest food. When enough gastric acid has been produced by the stomach, gastrin levels in the blood drop.
Gastrin also has minor effects on the pancreas, liver, and intestines. Gastrin helps the pancreas produce enzymes for digestion and helps the liver produce bile. It also stimulates the intestines to help move food through the digestive tract .
Sometimes a test for gastrin is done after eating a high-protein diet or after receiving an injection of the digestive hormone secretin into a vein. This is called an intravenous secretin test.
Why It Is Done
A gastrin test may be done to:
How To Prepare
Before having the gastrin test:
- Do not drink alcohol for 24 hours before the test.
- Do not eat for 12 hours before the test.
- Do not eat or drink anything with caffeine, such as coffee, for 12 hours before the test.
- Do not chew gum or smoke cigarettes for 4 hours before the test.
- You can drink as much water as you want up to 1 hour before the test.
Many medicines can change the results of this test. Be sure to tell your doctor about all the nonprescription and prescription medicines you take, especially acid-reducing medicines, such as Pepcid, Prilosec, Rolaids, Tums, or Zantac. You may need to stop taking some medicines before this test.
Stress can affect gastrin levels, so you may be asked to rest quietly for 30 minutes before the blood sample is drawn.
Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results will mean. To help you understand the importance of this test, fill out the medical test information form(What is a PDF document?).