Gastrin

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Formal name: Gastrin
Related tests: Helicobacter pylori, Gastric Acid

At a Glance

Why Get Tested?

To detect an overproduction of gastrin, to help diagnose Zollinger-Ellison syndrome and G-cell hyperplasia, and to monitor for recurrence of a gastrin-producing tumor (gastrinoma)

When to Get Tested?

When you have peptic ulcers and/or diarrhea and abdominal pain that your doctor suspects is caused by excess gastrin; periodically to monitor for a gastrinoma recurrence

Sample Required?

A blood sample drawn from a vein in your arm

Test Preparation Needed?

You should fast for 12 hours and avoid alcohol for 24 hours prior to the test. Your doctor may also ask you to refrain from taking certain stomach medications for several days prior to the test.

The Test Sample

What is being tested?

Gastrin is a hormone produced by "G-cells" in the stomach. It regulates the production of acid in the stomach during the digestive process. This test measures the amount of gastrin in the blood to help evaluate an individual with recurrent peptic ulcers and/or other serious abdominal symptoms.

When food is eaten, the stomach becomes less acidic, stimulating the release of gastrin. Gastrin in turn stimulates parietal cells to produce gastric acid. As acidity increases in the stomach, food is broken down and gastrin release is suppressed. This feedback system normally results in low to moderate concentrations of gastrin in the blood. Rare conditions such as G-cell hyperplasia and Zollinger-Ellison (ZE) syndrome can cause an overproduction of gastrin and gastric acid. This can lead to aggressive peptic ulcers that can be difficult to treat.

ZE syndrome is characterized by high gastrin levels, greatly increased gastric acid production, and by peptic ulcers due to gastrin-producing tumors called gastrinomas. Gastrinomas can form in the pancreas, the duodenum, and rarely in other parts of the body. More than half of them are malignant – causing cancer that can spread to other parts of the body, such as the liver. Even tiny tumors can produce large quantities of gastrin.

How is the sample collected for testing?

A blood sample is obtained by inserting a needle into a vein in the arm.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

You should fast for 12 hours and avoid alcohol for 24 hours prior to the test. Your doctor may also ask you to refrain from taking certain stomach medications for several days prior to the test.

The Test

Common Questions

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Article Sources

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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.

Sources Used in Current Review

Dugdale, D. (Updated 2011 August 5). Gastrin - blood test. MedlinePlus Medical Encyclopedia. [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003697.htm. Accessed October 2012.

(© 1995-2012). Gastrin, Serum. Mayo Clinic Mayo Medical Laboratories [On-line information]. Available online at http://www.mayomedicallaboratories.com/test-catalog/Overview/8512 through http://www.mayomedicallaboratories.com. Accessed October 2012.

(Revised 2012 January 13). How is pancreatic cancer diagnosed? American Cancer Society [On-line information]. Available online at http://www.cancer.org/Cancer/PancreaticCancer/DetailedGuide/pancreatic-cancer-diagnosis through http://www.cancer.org. Accessed October 2012.

Bishnu D. (Updated 2012 April 10). Gastrin. Medscape Reference [On-line information]. Available online at http://emedicine.medscape.com/article/2089092-overview through http://emedicine.medscape.com. Accessed October 2012.

(Modified 2012 February 6). General Information About Pancreatic Neuroendocrine Tumors (Islet Cell Tumors). National Cancer Institute [On-line information]. Available online at http://www.cancer.gov/cancertopics/pdq/treatment/isletcell/patient/ through http://www.cancer.gov. Accessed October 2012.

Bonheur, J. and Nachimuthu, S. (Updated 2012 January 25). Gastrinoma. Medscape Reference [On-line information]. Available online at http://emedicine.medscape.com/article/184332-overview through http://emedicine.medscape.com. Accessed October 2012.

(Updated 2012 May 10). Zollinger-Ellison Syndrome. National Institute of Diabetes and Digestive and Kidney Diseases [On-line information]. Available online at http://digestive.niddk.nih.gov/ddiseases/pubs/zollinger/ through http://digestive.niddk.nih.gov. Accessed October 2012.

Pagana, K. D. & Pagana, T. J. (© 2011). Mosby's Diagnostic and Laboratory Test Reference 10th Edition: Mosby, Inc., Saint Louis, MO. Pp 478-479.

Sources Used in Previous Reviews

Pagana, Kathleen D. & Pagana, Timothy J. (© 2007). Mosby's Diagnostic and Laboratory Test Reference 8th Edition: Mosby, Inc., Saint Louis, MO. Pp 471-472.

Clarke, W. and Dufour, D. R., Editors (2006). Contemporary Practice in Clinical Chemistry, AACC Press, Washington, DC. Pp 301, 303.

Wu, A. (2006). Tietz Clinical Guide to Laboratory Tests, Fourth Edition.  Saunders Elsevier, St. Louis, Missouri. Pp 432-435.

Hurd, R. (2007 October 24). Gastrin. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003697.htm. Accessed on 10/11/08.

Stone, C. (2008 February 20, Updated). Zollinger-Ellison syndrome. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/000325.htm. Accessed on 10/11/08.

Livstone, E. (2007 December, Revised). Pancreatic Endocrine Tumors. Merck Manual Home Edition [On-line information]. Available online at http://www.merck.com/mmhe/sec09/ch131/ch131l.html#sec09-ch131-ch131l-950 through http://www.merck.com. Accessed on 10/11/08.

(2008 April). Your Digestive System and How it Works. National Digestive Diseases Information Clearinghouse [On-line information]. Available online at http://digestive.niddk.nih.gov/ddiseases/pubs/yrdd/ through http://digestive.niddk.nih.gov. Accessed on 10/11/08.

Meikle, A. W. (2008 July, Updated). Zollinger-Ellison Syndrome – Gastrinoma. ARUP Consult [On-line information]. Available online at http://www.arupconsult.com/Topics/OncologicDz/NeuroendocrineTumors/Gastrinoma.html# through http://www.arupconsult.com. Accessed on 10/18/08.

Bonheur, J. and Nachimuthu, S. (2006 June 27). Gastrinoma. EMedicine [On-line information]. Available online at http://www.emedicine.com/med/TOPIC2678.HTM through http://www.emedicine.com. Accessed on 10/11/08.