Preparation, Reasons & Results of Gastrin Blood Test

Submitted on March 27, 2012

Gastrin is a hormone produced in the stomach by special cells called G cells. This hormone helps to regulate the acid formed in the stomach. When food reaches the stomach, the levels of gastrin in the blood increases. This causes the stomach to release gastric acid that helps in the digestion of food. Blood gastrin levels start dropping when enough gastric acid has been produced.

Importance of Gastrin Test

A gastrin test is used to measure the amount of gastrin hormone contained in the blood. The test is done to diagnose problems associated with increased or reduced gastrin production.


A gastrin test is also sometimes called as a fasting serum gastrin test. The doctor could instruct the following before the test is performed:

  • Do not consume food for at least 12 hours before the test.
  • Do not consume alcohol for at least 24 hours before the test.
  • Do not smoke for at least 4 hours before the test.
  • Do not consume acid-reducing medicines for at least 12 hours before the test.

It is important to inform the doctor of any existing medication being taken as this can have an impact on the test results.

A gastrin test is a blood test that involves the collection of a blood sample from the vein in the upper arm. Gastrin levels are measured in pg/mL or picograms per milliliter. Gastrin values are different for adults and children.

Normal gastrin levels for adults should be less than 200 pg/mL, and for children, it should be lesser than 125 pg/mL.

Reasons for High Gastrin Levels

High gastrin levels could be due to

  • Chronic gastritis.
  • Hyperplasia: This condition is caused due to the excess production of gastrin.
  • Zollinger-Ellison syndrome: This condition is caused when gastrin causes a tumor in the stomach or small intestine.
  • Kidney failure.
  • Stomach cancer.
  • Diseases like hypercalcimia, hyperparathyroidism, and sarcoidosis.

Low gastrin levels may be due to hypothyroidism.

Test Results

Gastrin test results can be affected if the blood sugar levels are very low, if the individual has been consuming antidepressants, and if there was a recent stomach ulcer surgery.

In some cases where the gastrin levels are not too high, but the patient has been showing symptoms of a gastric disorder, a gastric stimulation test is ordered. Patients are injected with a serum called secretin for this test. This test can help to specifically identify the Zollinger-Ellison syndrome, which causes tumors in the small intestines.