Helicobacter Pylori Tests

Why It Is Done

A Helicobacter pylori ( H. pylori) test is done to:

• Find out whether an infection with H. pylori bacteria may be causing an ulcer or irritation of the stomach lining (gastritis).
• Find out whether treatment for an H. pylori infection has been successful.

How To Prepare

Blood antibody test

You do not need to do anything before you have a blood antibody test.

Stool antigen test

Medicines may change the results of this test. Be sure to tell your doctor about all the prescription and nonprescription medicines you take. Your doctor may recommend that you stop taking some of your medicines.

• Do not take antibiotics or medicines containing bismuth (such as Pepto-Bismol) for 1 month before the test.
• Do not take proton pump inhibitors (such as Nexium or Prilosec) for 2 weeks before the test.

Stomach biopsy or urea breath test

You will be asked to not eat or drink anything for a certain amount of time before having a breath test or a stomach biopsy. Follow your doctor's instructions about how long you need to avoid eating and drinking before the test.

Many medicines may change the results of this test. Be sure to tell your doctor about all the prescription and nonprescription medicines you take. Your doctor may recommend that you stop taking some of your medicines.

• Do not take antibiotics or medicines containing bismuth (such as Pepto-Bismol) for 1 month before the test.
• Do not take proton pump inhibitors for 2 weeks before the test.
• Do not take H2 blockers, such as Pepcid, Zantac, Axid, or Tagamet, for 24 hours before the test.

Talk to your doctor about any concerns you have about the need for the test, its risks, how it will be done, or what the results may mean. To help you understand the importance of this test, fill out the medical test information form (What is a PDF document?).

How It Is Done

Blood antibody test

The health professional taking a sample of your blood will:

• Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.
• Clean the needle site with alcohol.
• Put the needle into the vein. More than one needle stick may be needed.
• Attach a tube to the needle to fill it with blood.
• Remove the band from your arm when enough blood is collected.
• Put a gauze pad or cotton ball over the needle site as the needle is removed.
• Put pressure on the site and then put on a bandage.

Urea breath test

The breath sample is collected when you blow into a balloon or blow bubbles into a bottle of liquid. The health professional taking a sample of your breath will:

• Collect a sample of your breath before the test starts.
• Give you a capsule or some water to swallow that contains tagged or radioactive material.
• Collect samples of your breath at different times. The breath samples will be tested to see if they contain material formed when H. pylori comes into contact with the tagged or radioactive material.
• The urea breath test usually takes about 30 minutes.

Stool antigen test

The stool sample for this test may be collected at home. If you are in the hospital, a health professional will help you collect the sample.

To collect the sample, you need to:

• Pass stool into a dry container. Either solid or liquid stools can be collected. Be careful not to get urine or toilet tissue in with the stool sample.
• Replace the container cap and label the container with your name, your doctor's name, and the date the sample was collected.
• Wash your hands well after collecting the sample to avoid spreading bacteria.
• Deliver the sealed container as soon as possible to your doctor's office or directly to the lab.

Your doctor may also use a cotton swab inserted into your rectum to collect a stool sample during an exam.

Stomach biopsy

• Endoscopy is used to collect samples of tissue from the stomach and duodenum. The doctor may collect up to 10 tissue samples. To learn more, see the topic Upper Gastrointestinal Endoscopy.
• The tissue samples are tested in the lab to see if they contain H. pylori.
• In rare cases, a biopsy sample may be placed in a container with a substance that promotes the growth of H. pyloribacteria. This is called an H. pylori culture. If no bacteria grow, the culture is negative. If H. pyloribacteria grow, the culture is positive. Sometimes other tests are done to find the right medicine for treating the infection. This is called sensitivity testing.

How It Feels

Blood antibody test

The blood sample is taken from a vein in your arm. An elastic band is wrapped around your upper arm. It may feel tight. You may feel nothing at all from the needle, or you may feel a quick sting or pinch.

Urea breath test

A urea breath test does not normally cause discomfort.

Stool antigen test

Collecting a stool sample normally does not cause any discomfort.

If your doctor collects the sample during a rectal exam, you may feel some pressure or discomfort as the cotton swab is inserted into your rectum.

Stomach biopsy

You may notice a brief, sharp pain when the intravenous (IV) needle is placed in a vein in your arm. The local anesthetic sprayed into your throat usually tastes slightly bitter and will make your tongue and throat feel numb and swollen. Some people report that they feel as if they cannot breathe at times because of the tube in their throat, but this is a false sensation caused by the anesthetic. There is always plenty of breathing space around the tube in your mouth and throat. Remember to relax and take slow, deep breaths.

You may experience some gagging, nausea, bloating, or mild abdominal cramping as the tube is moved. Even though you won't be able to talk during the procedure because you have a tube in your throat, you can still communicate. If the discomfort is severe, alert your doctor with an agreed-upon signal or a tap on the arm.

The IV medicines will make you feel sleepy. Other side effects-such as heavy eyelids, difficulty speaking, a dry mouth, or blurred vision-may last for several hours after the test. The medicines may also cause you not to remember much of what happens during the test.

What Affects the Test

Reasons you may not be able to have the test or why the results may not be helpful include the following:

• Most urea breath tests now use tagged carbon rather than radioactive carbon. If you are pregnant, the radioactive urea breath test for H. pylori is not usually done, because the radiation could harm your child.
• Use of antibiotics may affect the results of the urea breath test, the stool antigen test, and stomach biopsy by reducing the number of H. pylori bacteria in the stomach and duodenum.
• The use of cimetidine (Tagamet), famotidine (Pepcid), lansoprazole (Prevacid), nizatidine (Axid), omeprazole (Prilosec), rabeprazole (Aciphex), ranitidine (Zantac), sucralfate (Carafate), or medicines containing bismuth (such as Pepto-Bismol) can also interfere with the results of the urea breath test, the stool antigen test, and stomach biopsy.
• A stomach biopsy may not detect an H. pylori infection that is present if the biopsy samples are taken from areas that are not infected by the H. pylori bacteria.
• Rough handling, contamination, or inadequate refrigeration of the blood sample can cause inaccurate blood antibody test results.
• When a blood antibody test is done early in an H. pylori infection, the results may be falsely negative because the level of antibodies is too low to measure.
• The likelihood of infection with H. pylori increases with age. Older adults are more likely to have detectable amounts of the bacteria in their body.

What To Think About

• Most urea breath tests now use tagged carbon rather than radioactive carbon. If you are pregnant, the radioactive urea breath test for H. pylori is not usually done, because the radiation could harm your child.
• The stool antigen test is the least expensive of the four tests for Helicobacter pylori, but it may not be as accurate as the other tests. The stomach biopsy is very accurate, but it is the most expensive and most risky of the four tests.
• A negative stool antigen test does not always mean that an H. pylori infection is not present (false-negative).
• Although many people are infected with H. pylori bacteria, only a few of them will develop peptic ulcer disease. For this reason, other factors (such as a person's symptoms) should be considered when interpreting the results of an H. pylori test.
• Blood tests for H. pylori may be positive for several years after the infection, so the urea breath test, the stool antigen test, or a biopsy may be used to find out if treatment has been effective.
• If your symptoms don't go away, an endoscopy may be needed. To learn more, see the topic Upper Gastrointestinal Endoscopy.
• Having an infection with H. pylori increases your chances of having cancer of the stomach. But the risk is very low.
• For some people who have taken medicine to treat a Helicobacter pylori ( H. pylori) infection, a follow-up test may be needed to make sure the infection is cured. The American College of Gastroenterology recommends a follow-up test to check for H. pylori infection whenever:^{footnote 1}
  • A peptic ulcer is caused by H. pylori infection.
  • Stomach (gastric) mucosa-associated lymphoid tissue (MALT) lymphoma is caused by H. pylori infection.
  • Upset stomach (dyspepsia) symptoms are present even after H. pylori infection was tested for and treated.
  • Resection of early stomach (gastric) cancer has been done.