Also Known As
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
This article was last reviewed on
This article waslast modified on 18 March 2021.
At a Glance
Why Get Tested?

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

When To Get Tested?

If you have gastrointestinal pain or symptoms of an ulcer

Sample Required?

A stool sample, blood sample from a vein, tissue biopsy of the stomach lining, or urea breath test

Test Preparation Needed?

No special preparation is needed for the blood test. For the urea breath test and if submitting a stool or having a biopsy you may be instructed to refrain from certain medications. If undergoing endoscopy, you may be instructed to fast after midnight the night prior to the procedure. Please follow any instructions given to you by a healthcare professional.

On average it takes 7 working days for the blood test results to come back from the hospital, depending on the exact tests requested. Some specialist test results may take longer, if samples have to be sent to a reference (specialist) laboratory. The X-ray & scan results may take longer. If you are registered to use the online services of your local practice, you may be able to access your results online. Your GP practice will be able to provide specific details.

If the doctor wants to see you about the result(s), you will be offered an appointment. If you are concerned about your test results, you will need to arrange an appointment with your doctor so that all relevant information including age, ethnicity, health history, signs and symptoms, laboratory and other procedures (radiology, endoscopy, etc.), can be considered.

Lab Tests Online-UK is an educational website designed to provide patients and carers with information on laboratory tests used in medical care. We are not a laboratory and are unable to comment on an individual's health and treatment.

Reference ranges are dependent on many factors, including patient age, sex, sample population, and test method, and numeric test results can have different meanings in different laboratories.

For these reasons, you will not find reference ranges for the majority of tests described on this web site. The lab report containing your test results should include the relevant reference range for your test(s). Please consult your doctor or the laboratory that performed the test(s) to obtain the reference range if you do not have the lab report.

For more information on reference ranges, please read Reference Ranges and What They Mean.

What is being tested?

These tests are looking for evidence of an infection in your gastrointestinal tract by a bacterium, known as Helicobacter pylori. This bacterium is known to be a major cause of peptic ulcer disease. H. pylori is also associated with the development of gastric (stomach) cancer.

How is the sample collected for testing?

The sample collected depends on the test your doctor requests. It may be as simple as submitting a stool sample to look for the H-pylori antigen or a blood sample taken from your vein to detect antibodies to the bacteria (tests if someone has had an infection).

A more invasive test will require a procedure called an endoscopy, which means putting a tube down the throat into the stomach to take a small piece of tissue (a biopsy) from the stomach lining. A biopsy can be used to detect other reasons for stomach pain, as well as be tested in the laboratory for H.pylori. H.pylori produces urease, a special enzyme that allows it to survive in the acidic environment of the stomach. The lab can detect the presence of this bacterium by looking for this enzyme in the tissue sample. The tissue may also be examined under a microscope by a pathologist, who will look for these bacteria or any other signs of disease that may explain your symptoms.

Sometimes a 13C-urea breath test can be used instead of a biopsy. This test is to diagnose active infection and to check for the successful eradication of H.pylori in patients with a peptic ulcer. In this case, the test may be performed at least one month after completion of treatment.

You will be asked to drink a fluid containing a naturally occurring substance called urea. This urea contains a form of carbon, known as 13C. If H.pylori is present in your stomach, the urea will be broken down leading to an increase in 13C in the carbon dioxide you breathe out. By testing the expelled air collected from your breath sample, we can determine if H.pylori is present in your body. The test is completely safe and does not involve the use of radiation.

Is any test preparation needed to ensure the quality of the sample?

No special preparation is needed for the blood test.

For the urea breath test you must have nothing to eat or drink except a glass of water and your medication on the day of the test. Smoking is also not advised on the day of the test. Please follow any instructions you are given and inform you healthcare professional of any medications you are taking, as some medications will interfere with the test results, and the test may need to be rearranged.

If submitting a stool or having a biopsy you may be instructed to refrain from certain medications.

If undergoing endoscopy, you may be instructed to fast after midnight the night prior to the procedure.

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Common Questions
  • How is it used?

    This test is used to diagnose infection due to Helicobacter pylori.  A positive test for H.pylori indicates that your gastrointestinal pain may be due to a peptic ulcer caused by this bacterium. Taking antibiotics will kill the bacteria and may stop the pain and the ulceration.

    Sometimes a test for H.pylori may be used to determine if treatment with antibiotics was effective, however the blood antibody test cannot be used for this purpose since antibodies to H.pylori may persist even after an infection is resolved.

  • When is it requested?

    If you come in complaining of gastrointestinal pain and symptoms of an ulcer, your doctor may request one of the H. pylori tests to determine if there is evidence of this disease. Some of these symptoms may include:

    • Indigestion
    • Feeling of fullness or bloating
    • Nausea
    • Belching and regurgitation

    These tests may also be requested after you finish taking the prescribed antibiotics to prove that the H. pylori bacteria have disappeared from your body. However, the blood antibody test cannot be used for this purpose since antibodies to H. pylori may persist even after an infection is resolved.

    A follow-up test is not performed on every patient.

  • What does the test result mean?

    A positive H. pylori test, antibody, antigen, or breath test indicates that you have been infected with this organism. In recent years, scientific data show that this bacteria causes stomach ulcers and appropriate treatment can destroy the bacteria and stop the disease.

    A negative blood antibody or stool antigen test may mean that you are not infected.  However, if your symptoms persist, you doctor may request the more invasive tissue biopsy to more conclusively rule out infection.


  • Is there anything else I should know?

    People have gastrointestinal pain for many reasons—H.pylori is only one of them.

    If a patient uses antacids within the week prior to testing, the rapid urease test may be falsely negative. Antimicrobials, proton pump inhibitors, and bismuth preparations may interfere with all but the blood antibody test.

  • What is the treatment of peptic ulcer caused by Helicobacter pylori?

    Usually the doctor will prescribe a combination of antibiotics and possibly a bismuth preparation, such as Pepto-Bismol®, for several weeks. 

    It is important to take the full course of antibiotics prescribed to ensure successful treatment.

  • Does everyone with H. pylori get ulcers?

    No, many people have evidence of infection but have no symptoms of ulcerative disease.

  • How did I get infected with H. pylori?

    The bacteria are transmitted by eating food or drinking water that has been contaminated with human faecal material. Animals do not carry the bacteria in their GI tracts; it is only found in humans. Peptic ulcer disease is one of the most common human ailments, affecting approximately two thirds of the world's population. In the UK and other developed countries, the infection rate is lower because of better hygiene and socioeconomic status.

  • Does everyone treated for H. pylori get better?

    The majority of people who successfully complete the combination antibiotic therapy get rid of this bacteria from their GI tract. However, resistance to some of the antibiotics may occur and therefore the bacteria may continue to multiply in spite of appropriate therapy.

  • My father had an ulcer and he only took antacids. Why do I need antibiotics?

    Years ago doctors did not know that Helicobacter pylori existed. Before 1994, peptic ulcers were not recognised as an infectious disease, so the only treatment prescribed for ulcers was a change in diet and antacids to stop the pain.

  • Are there any other ways of testing for H. pylori infection?

    Recently, some studies suggest that the use of molecular methods that detect the genetic material of H. pylori in gastric biopsy samples may be useful in diagnosing an infection.