Gastrin

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At a Glance

Why Get Tested?

To determine whether you are producing too much gastrin; to help diagnose Zollinger-Ellison syndrome and gastrin-producing tumors (gastrinomas) or G-cell hyperplasia; to monitor for recurrence of a gastrinoma

When To Get Tested?

When you have peptic ulcers and/or diarrhea and abdominal pain that your healthcare practitioner 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, including avoiding coffee and caffeine-containing drinks, and avoid alcohol for 24 hours prior to the test. Your health care practitioner may also ask you to refrain from taking certain stomach medications for several days prior to the test. Medications that can increase gastrin levels include antacids, H2-blocking agents (such as cimetidine), and proton pump inhibitors (such as omeprazole).

Looking For Test Results?

Looking For Reference Ranges?

You may be able to find your test results on your laboratory’s website or patient portal. However, you are currently at Testing.com. You may have been directed here by your lab’s website in order to provide you with background information about the test(s) you had performed. You will need to return to your lab’s website or portal, or contact your healthcare practitioner in order to obtain your test results.

Testing.com is an award-winning patient education website offering information on laboratory tests. The content on the site, which has been reviewed by laboratory scientists and other medical professionals, provides general explanations of what results might mean for each test listed on the site, such as what a high or low value might suggest to your healthcare practitioner about your health or medical condition.

The reference ranges for your tests can be found on your laboratory report. They are typically found to the right of your results.

If you do not have your lab report, consult your healthcare provider or the laboratory that performed the test(s) to obtain the reference range.

Laboratory test results are not meaningful by themselves. Their meaning comes from comparison to reference ranges. Reference ranges are the values expected for a healthy person. They are sometimes called “normal” values. By comparing your test results with reference values, you and your healthcare provider can see if any of your test results fall outside the range of expected values. Values that are outside expected ranges can provide clues to help identify possible conditions or diseases.

While accuracy of laboratory testing has significantly evolved over the past few decades, some lab-to-lab variability can occur due to differences in testing equipment, chemical reagents, and techniques. This is a reason why so few reference ranges are provided on this site. It is important to know that you must use the range supplied by the laboratory that performed your test to evaluate whether your results are “within normal limits.”

For more information, please read the article Reference Ranges and What They Mean.

What is being tested?

Gastrin is a hormone produced by “G-cells” in the part of the stomach called the antrum. It regulates the production of acid in the body of 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 antrum of the stomach becomes distended and the presence of food stimulates the release of gastrin. Gastrin in turn stimulates parietal cells to produce gastric acid. Acidity helps to digest food and the rise in acidity eventually suppresses gastrin release. This feedback system normally results in low concentrations of gastrin in the blood, especially in the fasting state. Rare conditions such as G-cell hyperplasia and gastrinomas, including 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.

Gastrinomas are gastrin-producing tumors. ZE syndrome is a condition caused by the presence of one or more gastrinomas and is characterized by high gastrin levels, greatly increased gastric acid production, and by peptic ulcers. Gastrinomas usually form in the pancreas, even though the endocrine cells of the pancreas do not normally make gastrin. 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.

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 health care practitioner may also ask you to refrain from taking certain stomach medications for several days prior to the test. Medications that can increase gastrin levels include antacids, H2-blocking agents (such as cimetidine), and proton pump inhibitors (such as omeprazole). These prevent the normal negative feedback in which acidity suppresses gastrin production.

Common Questions

How is it used?

The gastrin test is primarily used to help detect excess production of gastrin and gastric acid. It is used to help diagnose gastrin-producing tumors called gastrinomas, Zollinger-Ellison (ZE) syndrome, and hyperplasia of G-cells. G-cells are specialized cells in the stomach that produce gastrin, which in turn increases the production of gastric acid.

A gastrin test may also be used to monitor for recurrence following the surgical removal of a gastrinoma.

A gastrin stimulation test therefore may be used to provide additional information if the initial gastrin test result is moderately but not significantly elevated and the healthcare practitioner suspects that a person’s symptoms are due to a gastrinoma. This procedure involves collecting a baseline gastrin sample, giving the patient a chemical (typically the hormone secretin) to stimulate gastrin production, and then collecting additional blood samples at timed intervals for gastrin testing. The other (benign) causes of elevated gastrin will not show an increase after secretin administration.

A measurement of gastric acid pH level may sometimes be ordered along with or following a gastrin test to help diagnose ZE syndrome.

When is it ordered?

A gastrin test may be ordered when a person has diarrhea, abdominal pain, and/or recurrent peptic ulcers that do not respond to treatment and that the healthcare practitioner suspects are due to excess gastrin production. A gastrin stimulation test may be ordered when a gastrin level is moderately elevated and the healthcare practitioner suspects that a person has a gastrinoma.

When a gastrin-producing tumor has been removed, a gastrin test may be ordered periodically as a screening test to monitor for recurrence.

What does the test result mean?

Low or normal blood levels of gastrin are not typically of concern.

Moderately increased levels may be seen with a variety of conditions such as ZE syndrome, G-cell hyperplasia, chronic atrophic gastritis (a condition resulting from long-term inflammation of the stomach lining that leads to the loss of acid-producing cells), pernicious anemia, a pyloric obstruction (blockage at the junction of the stomach and duodenum), and chronic kidney failure.

Greatly increased levels of gastrin in symptomatic individuals and concentrations of gastrin that increase significantly during a gastrin stimulation test indicate the likelihood that a person has ZE syndrome and one or more gastrinomas. Imaging tests may be ordered as a follow up to high gastrin concentrations to locate the gastrinoma(s). The quantity of gastrin produced is not related to either the tumor size or to the number of tumors. Even tiny tumors can produce large amounts of gastrin.

Gastrin levels that were initially low after the surgical removal of a gastrinoma and then increase may signal a recurrence of the tumor. Concentrations that do not decrease after treatment may indicate that the treatment has not been fully effective.

Is there anything else I should know?

Gastrinomas can affect anyone, but people who have an inherited condition called MEN-1 (Multiple Endocrine Neoplasia, type 1) are at an increased risk. These people have genetic alterations that increase their lifetime risk of developing tumors in their pancreas or in another of their endocrine glands.

It is important to note that most stomach ulcers are not due to gastrinomas. They are commonly associated with Helicobacter pylori infections and sometimes with the use of nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen.

Gastrin levels commonly increase with age and with prolonged use of medications such as antacids and proton pump inhibitors that neutralize or inhibit the production of stomach acid. They will also typically be elevated in people who are not fasting. Increases in gastrin concentration with age may reflect a general decrease in the ability to produce stomach acid.

Gastrin blood levels follow a circadian rhythm. This means that they will be at their lowest between about 3 to 7 AM. Concentrations will be higher during the day and will fluctuate in response to meals.

What is Zollinger-Ellison syndrome?

Zollinger-Ellison (ZE) syndrome is a rare disease of the gastrointestinal tract. It is characterized by severe recurrent peptic ulcers in the stomach, duodenum and/or the upper portion of the small intestine. The ulcers are caused by a greatly increased amount of stomach acid due to high levels of gastrin, the hormone that stimulates stomach acid production. In ZE, high gastrin levels are caused by gastrin-producing tumors called gastrinomas, which usually form in the duodenum but can be found in the pancreas and rarely in other parts of the body. More than half of them are malignant and can metastasize to other parts of the body, such as the liver. The tumors must be removed surgically, and sometimes total removal of the stomach is necessary to control the acid production.

How long will it take to get the results of my gastrin test?

Gastrin testing is performed using specialized equipment in a laboratory and not every laboratory will offer gastrin testing. In some cases, your sample may need to be sent to a reference laboratory and results may take a few days.

Can’t I just take stomach medicines to address my excess gastrin and stomach acid?

Stomach medications such as proton pump inhibitors may be prescribed as part of your treatment, but it is important to diagnose your underlying condition. Although gastrinomas are rare, more than half of them are cancerous and can spread to other parts of your body.

Related Content

On This Site

Tests: Helicobacter pylori

Elsewhere On The Web

NIDDK: The Digestive System and How it Works
NIDDK: Peptic Ulcers (Stomach Ulcers)
The National Pancreas Foundation: Zollinger-Ellison Syndrome/Gastrinoma
MayoClinic.com: Zollinger-Ellison syndrome
GeneReviews: Multiple Endocrine Neoplasia Type 1
MedlinePlus Medical Encyclopedia: Zollinger-Ellison syndrome

View Sources

Sources Used in Current Review

U.S. National Library of Medicine. (24 July 2015 updated.) Gastrin Blood Test. Available online at https://medlineplus.gov/ency/article/003697.htm. Accessed March 2017.

Mayo Medical Laboratories. Gastrin, Serum. Available online at http://www.mayomedicallaboratories.com/test-catalog/Clinical+and+Interpretive/8512. Accessed March 2017.

Devkota BP. (17 January 2014 updated.) Gastrin. Available online at http://emedicine.medscape.com/article/2089092-overview#a4. Accessed March 2017.

Healthwise Staff. (9 September 2014 updated.) Gastrin. Available online at http://www.webmd.com/digestive-disorders/gastrin#1. Accessed March 2017.

Pagana, Kathleen D., Pagana, Timothy J., and Pagana, Theresa N. (© 2015). Mosby’s Diagnostic and Laboratory Test Reference. 12th Edition: Mosby, Inc., Saint Louis, MO. Pp 456-457.

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. 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/. 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#. Accessed on 10/18/08.

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

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

 

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