What happens during the H. pylori breath test?

During the H. pylori breath test, you will be asked to exhale into a balloon-like bag. The amount of carbon dioxide you exhale into this bag is measured to provide a baseline level for comparison.

Next, you will be asked to drink a small amount of a pleasant lemon-flavored solution. The solution contains a substance called urea. Fifteen minutes after drinking the solution, you will exhale into a second bag. The amount of carbon dioxide you exhale into the second bag is also measured.

H. pylori bacteria (if present) breaks down the urea in the solution you drank, releasing carbon dioxide in the breath you exhale. So if the amount of carbon dioxide in your second sample is higher than the amount in your first sample, you have a positive test for the presence of H. pylori.

What steps do I need to take before the procedure?

Be sure to tell your healthcare provider if you are allergic to any medicines or if you are phenylketonuric. Follow these instructions:


  • Four weeks before your test, do not take any antibiotics or Pepto-Bismol® (oral bismuth subsalicylate).
  • Two weeks before your test do not take any over-the-counter or prescription proton pump inhibitors, such as omeprazole (Prilosec®), lansoprazole (Prevacid®), pantoprazole (Protonix®), rabeprazole (AcipHex®) or esomeprazole (Nexium®), dexlansoprazole (Dexilant®).

Do not stop taking any other medicine without first talking with your healthcare provider.

Food and drinks:

  • One hour before the test, do not eat or drink anything (including water).

On the day of the procedure

A healthcare provider will explain the procedure in detail and answer any questions you might have. The procedure lasts about 20 to 30 minutes.

After the procedure

  • Your breath samples are sent to the laboratory where they are tested.
  • You may resume your normal activities.
  • No restrictions.

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