DefinitionGastrin 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 performedA blood sample is needed. For information on how this is done, see: VenipunctureHow to prepare for the testCertain 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 feelWhen 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 performedYour 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.Normal ValuesNormal values are generally less than 100 pg/mL (picograms per milliliter).Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.The examples above show the common measurements for results for these tests. Some laboratories use different measurements or may test different specimens.What abnormal results meanToo much gastrin causes severe peptic ulcer disease. Greater-than-normal levels may also be due to:Chronic kidney diseaseLong-term gastritisOveractivity of the gastrin-producing cells in the stomach (G-cell hyperplasia)Helicobacter pylori infection of the stomachUse of antacids or medicines to treat heartburnZollinger-Ellison syndrome, a gastrin-producing tumor that may develop in the stomach or pancreasWhat the risks areVeins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.Other risks associated with having blood drawn are slight but may include:Excessive bleedingFainting or feeling light-headedHematoma (blood accumulating under the skin)Infection (a slight risk any time the skin is broken)ReferencesJensen RT. Pancreatic endocrine tumors. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 201.Reviewed ByReview Date: 08/05/2011David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.