Definition of Gastrin - blood test:

Gastrin is the major hormone that controls the release of acid in your stomach. When there is food in the stomach, gastrin is released into the blood. As the acid level rises in your stomach and intestines, your body normally makes less gastrin.

A laboratory test can be done to measure the amount of gastrin in the blood.

How the test is performed:

A blood sample is needed. For information on how this is done, see: Venipuncture

How to prepare for the test:

Certain drugs may interfere with the results of this test. Your doctor will tell you if you need to stop taking any medicines. Do not stop taking any medicines before talking to your doctor.

Drugs that can increase gastrin measurements include antacids, H2-blocking agents (such as cimetidine), and proton pump inhibitors (such as omeprazole).

How the test will feel:

When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.

Why the test is performed:

Your doctor may order this test if you have signs or symptoms of a disorder linked to abnormal amounts of gastrin. This includes peptic ulcer disease.