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H pylori Testing

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Also known as: H. pylori; H-pylori; H. pylori antibody test; H. pylori stool antigen test; H. pylori breath test; Urea breath test; CLO test; Rapid urease test (RUT) for H. pylori
Formal name: Helicobacter pylori
Related tests: Gastrin

At a Glance

Why Get Tested?

To diagnose an infection with Helicobacter pylori, bacteria that can cause peptic ulcers

When to Get Tested?

When you have symptoms of an ulcer, such as gastrointestinal pain that comes and goes, unexplained weight loss, nausea and/or vomiting

Sample Required?

A stool sample, a breath sample, or a tissue biopsy of the stomach lining

Test Preparation Needed?

You may need to avoid certain medications; follow any instructions you are given.

The Test Sample

What is being tested?

Helicobacter pylori is a type of bacteria that is known to be a major cause of peptic ulcer disease. H. pylori testing detects an infection of the gastrointestinal (GI) tract caused by the bacteria.

H. pylori is very common, especially in developing countries. The bacteria are present in (colonize) the stomachs and intestines of as many as 50% of the world's population. Most of those affected will never have any symptoms, but the presence of H. pylori increases the risk of developing ulcers (peptic ulcer disease), chronic gastritis, and gastric (stomach) cancer. The bacteria decrease the stomach's ability to produce mucus, making the stomach prone to acid damage and peptic ulcers.

There are several different types of H. pylori testing that can be performed. Some are less invasive than others.


  • Stool antigen test – detection of H. pylori in a stool sample
  • Urea breath test – detection of labeled carbon dioxide in the breath after drinking a solution 

Recommendations for these tests come from published guidelines by the American Gastroenterology Association (AGA), the American College of Gastroenterologists (ACG), and the Infectious Diseases Society of America (IDSA) / the American Society for Microbiology (ASM).

An antibody test using a blood sample is not recommended for routine diagnosis or for evaluation of treatment effectiveness. This test detects antibodies to the bacteria and will not distinguish between a present and previous infection. If the antibody test is negative, then it is unlikely that a person has had an H. pylori infection. If ordered and positive, results should be confirmed using a stool antigen or breath test.


Invasive tests using an endoscopy procedure are less frequently performed than noninvasive tests because they require a tissue biopsy collection. Tests include:

  • Histology – examination of tissue under a microscope
  • Rapid urease testing – detects urease, an enzyme produced by H. pylori
  • Culture – growing H. pylori in/on a nutrient solution

How is the sample collected for testing?

The sample collected depends on the test ordered. For the urea breath test, a breath sample is collected and then the person is given a liquid to drink. Another breath sample is collected at a timed interval. For the stool antigen test, a stool sample is collected in a clean container.

A more invasive test will require a procedure called an endoscopy, which involves putting a thin tube with a tiny camera on the end down the throat into the stomach. This allows for visualization of the stomach lining as well as the ability to take a small piece of tissue (a biopsy) from the lining for examination.

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?

For the breath test, you may be instructed to refrain from taking certain medications:

  • Four weeks before the test, do not take any antibiotics or oral bismuth subsalicylate (Pepto Bismol®).
  • Two weeks before the test, do not take any prescription or over-the-counter proton pump inhibitors, such as omeprazole, lansoprazole, or esomeprazole.
  • One hour before the test, do not eat or drink anything (including water).

If submitting a stool sample or having a tissue biopsy collected, it may be necessary to refrain from taking any antibiotics, antacids, or bismuth treatments for 14 days prior to the test.

If undergoing endoscopy, fasting after midnight on the night prior to the procedure may be required.

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

Baumann, A. and Katz, P. (Updated 2014 January 27). Helicobacter Pylori Antigen Test. Medscape Drugs & Diseases [On-line information]. Available online at through Accessed October 2014.

Santacroce, L. and Bhutani, M. (Updated 2014 September 11). Helicobacter Pylori Infection. Medscape Drugs & Diseases [On-line information]. Available online at through Accessed October 2014.

Longstreth, G.(Updated 2013 August 22). Tests for H pylori. MedlinePlus Medical Encyclopedia [On-line information]. Available online at through Accessed October 2014.

DiMarino, M. (Revised 2014 May). Helicobacter pylori Infection. The Merck Manual Professional Edition [On-line information]. Available online through Accessed October 2014.

(© 1995–2014). Helicobacter pylori Antibody, IgA, Serum. Mayo Clinic Mayo Medical Laboratories [On-line information]. Available online at through Accessed October 2014.

(2013 November). Helicobacter pylori Infection: Test Utilization Strategies for Diagnosis. Communique, Mayo Clinic Mayo Medical Laboratories [On-line information]. Available online at through Accessed October 2014.

Kelly, J. (2014 September 30). WHO Urges H pylori Screening to Prevent Gastric Cancer. Medscape News [On-line information]. Available online at through Accessed October 2014.

Baron, E. et. al. (2013 July 10). A Guide to Utilization of the Microbiology Laboratory for Diagnosis of Infectious Diseases: 2013 Recommendations by the Infectious Diseases Society of America (IDSA) and the American Society for Microbiology (ASM). [On-line information]. Available online through Accessed October 2014.

Pagana, K. D., Pagana, T. J., and Pagana, T. N. (© 2015). Mosby's Diagnostic & Laboratory Test Reference 12th Edition: Mosby, Inc., Saint Louis, MO. Pp 494-496.

Sources Used in Previous Reviews

The Cleveland Clinic Health Information Center. Breath Test for H. pylori (Online information). Available online at Accessed February 2008.

Pagana K, Pagana T. Mosby's Manual of Diagnostic and Laboratory Tests. 3rd Edition, St. Louis: Mosby Elsevier; 2006.

Forbes BA, Sahm DF, Weissfeld AS. Bailey & Scott's Diagnostic Microbiology 12th Edition: Mosby Elsevier, St. Louis, MO; 2007.

Chisholm SA, Owen RJ. Application of polymerase chain reaction-based assays for rapid identification and antibiotic resistance screening of Helicobacter pylori in gastric biopsies. Diagn Microbiol Infect Dis. 2008 Jan 11.

Siddique I, et. al Diagnosis of Helicobacter pylori: Improving the Sensitivity of CLOtest by Increasing the Number of Gastric Antral Biopsies. J Clin Gastroenterol. 2008 Apr;42(4):356-360.

Clinical Chemistry: Principles, Procedures, Correlations. Bishop M, Duben-Engelkirk J, Fody E, eds. 4th ed. Philadelphia: Lippincott Williams & Wilkins; 2000.

Clinical Chemistry: Theory, Analysis, and Correlations. Kaplan L, Pesce A, eds. 2nd ed. St. Louis: The C. V. Mosby Company; 1989.

National Digestive Diseases Information Clearinghouse. H. pylori and Peptic Ulcer. Available online at through Accessed June 2011.

Michael Selgrad, Arne Kandulski and Peter Malfertheiner. Helicobacter pylori: Diagnosis and Treatment: Diagnosis of Helicobacter pylori. Curr Opin Gastroenterol. 2009;25(6):549-556. Available online at through Accessed June 2011.