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Tests for H. pylori

Helicobacter pylori (H. pylori) is the bacteria (germ) responsible for most stomach and duodenal ulcers and many cases of stomach inflammation (chronic gastritis).

How the Test is Performed

There are several methods to test for H. pylori infection.

Breath Test (Carbon Isotope-urea Breath Test, or UBT)

  • Up to 2 weeks before the test, you need to stop taking antibiotics, bismuth medicines such as Pepto-Bismol, and proton pump inhibitors (PPIs).
  • During the test, you swallow a special substance that has urea. Urea is a waste product the body produces as it breaks down protein. The urea used in the test has been made harmlessly radioactive.
  • If H. pylori are present, the bacteria convert the urea into carbon dioxide, which is detected and recorded in your exhaled breath after 10 minutes.
  • This test can identify almost all people who have H. pylori. It can also be used to check that the infection has been fully treated.

Blood Tests

  • Blood tests are used to measure antibodies to H. pylori. Antibodies are proteins made by the body's immune system when it detects harmful substances such as bacteria.
  • Blood tests for H. pylori can only tell if your body has H. pylori antibodies. It cannot tell if you have a current infection or how long you have had it. This is because the test can be positive for years, even if the infection is cured. As a result, blood tests cannot be used to see if the infection has been cured after treatment.

Stool Test

  • A stool test can detect traces of H. pylori in the feces.
  • This test can be used to diagnose the infection and confirm that it has been cured after treatment.


  • A tissue sample, called biopsy, that is taken from the stomach lining is the most accurate way to tell if you have an H. pylori infection.
  • To remove the tissue sample, you have a procedure called endoscopy. The procedure is done in the hospital.
  • Usually, a biopsy is done if endoscopy is needed for other reasons. Reasons include diagnosing the ulcer, treating bleeding, or making sure there is no cancer.

Why the Test is Performed

Testing is most often done to diagnose H. pylori infection:

  • If you currently have a stomach or duodenal ulcer
  • If you had a stomach or duodenal ulcer in the past, and were never tested for H. pylori
  • After treatment for H. pylori infection, to make sure there are no more bacteria

Testing may also be done if you need to take long-term ibuprofen or other NSAID medicines. Your health care provider can tell you more.

The test may also be recommended for a condition called dyspepsia. This is upper abdominal discomfort. Symptoms include a feeling of fullness or of heat, burning, or pain in the area between the navel and the lower part of the breastbone during or after eating. Testing for H. pylori without endoscopy is most often done only when the discomfort is new, the person is younger than 55, and there are no other symptoms.

Normal Results

Normal results mean there is no sign that you have an H. pylori infection.

What Abnormal Results Mean

Abnormal results mean that you have an H. pylori infection. Your provider will discuss treatment with you.

Alternative Names

Peptic ulcer disease - H. pylori; PUD - H. pylori


Cover TL, Blaser MJ. Heliobacter pylori and other gastric Heliobacter species. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 8th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 219.

Morgan DR, Crowe SE. Heliobacter pylori infection. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease: Pathophysiology/Diagnosis/Management. 10th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 51.

Salwen MJ, Siddiqi HA, Gress FG, Bowne WB. Laboratory diagnosis of gastrointestinal and pancreatic disorders. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 22.

Review Date 8/14/2015

Updated by: Subodh K. Lal, MD, gastroenterologist at Gastrointestinal Specialists of Georgia, Austell, GA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

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