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Helicobacter pylori breath test

What is this test?

This test detects the activity of urease by measuring carbon dioxide (CO2) gas in air that is exhaled (breathed out). Urease is an enzyme produced by the bacteria Helicobacter pylori (H. pylori). This test is done after drinking a liquid that contains urea. It is used to help diagnose and manage a H. pylori infection[1][2] such as H. pylori gastritis[3][4][5][6].

Why do I need this test?

Laboratory tests may be done for many reasons. Tests are performed for routine health screenings or if a disease or toxicity is suspected. Lab tests may be used to determine if a medical condition is improving or worsening. Lab tests may also be used to measure the success or failure of a medication or treatment plan. Lab tests may be ordered for professional or legal reasons. You may need this test if you have:

When and how often should I have this test?

When and how often laboratory tests are done may depend on many factors. The timing of laboratory tests may rely on the results or completion of other tests, procedures, or treatments. Lab tests may be performed immediately in an emergency, or tests may be delayed as a condition is treated or monitored. A test may be suggested or become necessary when certain signs or symptoms appear.

Due to changes in the way your body naturally functions through the course of a day, lab tests may need to be performed at a certain time of day. If you have prepared for a test by changing your food or fluid intake, lab tests may be timed in accordance with those changes. Timing of tests may be based on increased and decreased levels of medications, drugs or other substances in the body.

The age or gender of the person being tested may affect when and how often a lab test is required. Chronic or progressive conditions may need ongoing monitoring through the use of lab tests. Conditions that worsen and improve may also need frequent monitoring. Certain tests may be repeated to obtain a series of results, or tests may need to be repeated to confirm or disprove results. Timing and frequency of lab tests may vary if they are performed for professional or legal reasons.

How should I get ready for the test?

Fast overnight before the test[5][7][2].

Tell the person doing the test if you are pregnant or breast feeding, have used antibiotics or bismuth preparations within four weeks, or have a history of gastric (stomach) conditions or surgeries[5].

How is the test done?

Methods used to collect for this test vary. Depending on the method used, you may be asked to drink a liquid test meal or water containing a fixed amount of urea[1][7][2]. Breath samples will be collected by blowing through a drinking straw into a bottle of liquid containing test solutions[5]. Ask the healthcare worker to explain the details of this test to you.

How will the test feel?

The amount of discomfort you feel will depend on many factors, including your sensitivity to pain. Communicate how you are feeling with the person doing the test. Inform the person doing the test if you feel that you cannot continue with the test.

What should I do after the test?

There are no special instructions to follow after this test.

What are the risks?

Ask the healthcare worker to explain the risks of this test or procedure to you before it is performed.

What are normal results for this test?

Laboratory test results may vary depending on your age, gender, health history, the method used for the test, and many other factors. If your results are different from the results suggested below, this may not mean that you have a disease. Contact your healthcare worker if you have any questions. The following is considered to be a normal result for this test:

Adults and Children: Below cut-off value for radiolabeled CO2[1]

What might affect my test results?

Drug Therapy Use:

Some medications may affect the results of the test. These medications include:

What follow up should I do after this test?

Ask your healthcare worker how you will be informed of the test results. You may be asked to call for results, schedule an appointment to discuss results, or notified of results by mail. Follow up care varies depending on many factors related to your test. Sometimes there is no follow up after you have been notified of test results. At other times follow up may be suggested or necessary. Some examples of follow up care include changes to medication or treatment plans, referral to a specialist, more or less frequent monitoring, and additional tests or procedures. Talk with your healthcare worker about any concerns or questions you have regarding follow up care or instructions.

Where can I get more information?

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[1] Dunn BE, Cohen H, & Blaser MJ: Helicobacter pylori. Clin Microbiol Rev 1997; 10(4):720-741.

[2] Rauws EAJ, Royen EAV, Langenberg W, et al: 14C-Urea breath test in C. pylori gastritis. Gut 1989; 30:798-803.

[3] Dunn BE, Cohen H, & Blaser MJ: Helicobacter pylori. Clin Microbiol Rev 1997; 10:720-741. Available from URL: As accessed February 11, 2005.

[4] Cutler AF: Testing for Helicobacter pylori in clinical practice. Am J Med 1996; 100:35S-41S.

[5] Faigel DO, Childs M, Furth EE, et al: New noninvasive tests for Helicobacter pylori gastritis. Digest Dis Sci 1996; 41:740-748.

[6] Mertz H, Lafrance N, Kafonek D, et al: Diagnosis of Campylobacter pylori gastritis. Digest Dis Sci 1991; 36:1-4.

[7] Atherton JC & Spiller RC: The urea breath test for Helicobacter pylori. Gut 1994; 35:723-725.

Last Updated: 3/29/2016

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