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

Peptic ulcer disease - H pylori; PUD - H pylori

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.

Biopsy

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

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 of these 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 (indigestion). 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 EGD is most often done only when the discomfort is new, the person is younger than 55, and there are no other symptoms.

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

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

Cover TL, Blaser MJ. Helicobacter pylori and other gastric Helicobacter species. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 217.

Siddiqi HA, Rabinowitz S, Axiotis CA. Laboratory diagnosis of gastrointestinal and pancreatic disorders. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 23.