This test measures the amount of gastrin in your blood. Gastrin is a hormone made by G cells in the lower part of your stomach. It controls the release of gastric acid to help break down food.
You may need this test if your healthcare provider wants to check for high levels of gastrin. This test also helps to diagnose and monitor different conditions. They include:
Gastrinomas. Tumors that produce gastrin.
Zollinger-Ellison (ZE) syndrome. A rare condition with tumors in the small intestine or pancreas.
G-cell hyperplasia. Cells in the stomach make too much gastrin.
You may also have lab tests like a gastric acid level, a pH test to measure the acid in your stomach juices, or other tests that check gastrin production. You may also have imaging tests.
Test results may vary depending on your age, gender, health history, the method used for the test, and other things. Your test results may not mean you have a problem. Ask your healthcare provider what your test results mean for you.
The results are usually expressed in picograms per milliliter of blood (pg/mL). The normal range is:
0 to 180 pg/mL for adults
0 to 125 pg/mL for children
Your levels may be higher if you are an older adult.
Patients with ZE syndrome or G-cell hyperplasia usually have levels of gastrin in their blood that are quite high. But you could have ZE syndrome without high levels of blood gastrin. Other conditions and some medicines can also raise gastrin levels.
The test is done with a blood sample. A needle is used to draw blood from a vein in your arm or hand.
Having a blood test with a needle carries some risks. These include bleeding, infection, bruising, and feeling lightheaded. When the needle pricks your arm or hand, you may feel a slight sting or pain. Afterward, the site may be sore.
Things that may affect your test results include:
Having peptic ulcer surgery
Eating a lot of high-protein foods
Taking insulin to treat diabetes
Taking antacids or other medicines that block gastric acid production
Taking calcium supplements
Having drinks, food, or medicine with caffeine
Taking antidepressants, which can lower your gastrin levels
You must fast for 12 hours before the test. You can drink water. Ask your healthcare provider if there are any medicines that you should stop taking before the test. Do not drink alcohol for at least 24 hours before having this test. Be sure your healthcare provider knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illicit drugs you may use.