Helicobacter pylori Tests

Helicobacter pylori tests are used to detect a Helicobacter pylori (H. pylori) infection in the stomach and upper part of the small intestine (duodenum). H. pylori can cause peptic ulcers; however, most people with H. pylori in their digestive systems do not develop ulcers.

Four tests are used to detect H. pylori:

• Blood antibody test. A blood test checks to see whether your body has made antibodies to H. pylori bacteria. If you have antibodies to H. pylori in your blood, it means you either are currently infected or have been infected in the past.
• Urea breath test. A urea breath test checks to see if you have H. pylori bacteria in your stomach. The breath test is not always available.
• Stool antigen test. A stool antigen test checks to see if substances that trigger the immune system to fight an H. pylori infection (H. pylori antigens) are present in your feces (stool). Stool antigen testing may be done to help support a diagnosis of H. pylori infection or to determine whether treatment for an H. pylori infection has been successful.
• Stomach biopsy. A small sample (biopsy) is taken from the lining of your stomach and small intestine during an endoscopy. Several different tests may be done on the biopsy sample. For more information, see the medical test Upper Gastrointestinal Endoscopy.

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

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

Blood antibody test or stool antigen test

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

Stomach biopsy or urea breath test

Do not eat or drink for at least 6 hours before a breath test or a stomach biopsy.

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 for up to 1 week before having this test.

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

Talk to your health professional about any concerns you have regarding 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?).

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 whether they contain material formed when H. pylori comes into contact with the radioactive material.
• The urea breath test usually takes about 1.5 hours.

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 ten tissue samples. For more information, see the medical test 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 that promotes the growth of H. pylori bacteria. This is called an H. pylori culture. If bacteria grow in the culture, tests (called susceptibility or sensitivity testing) can determine which antibiotic to use to treat the infection.

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 medications 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 medications may also cause you not to remember much of what happens during the test.

Blood antibody test

There is very little chance of a problem from having a blood sample taken from a vein.

• You may get a small bruise at the site. You can lower the chance of bruising by keeping pressure on the site for several minutes.
• In rare cases, the vein may become swollen after the blood sample is taken. This problem is called phlebitis. A warm compress can be used several times a day to treat this.
• Ongoing bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other medicines that thin your blood can make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medicine, tell your doctor before your blood sample is taken.

Urea breath test

There are no known risks or complications with a urea breath test. If radioactive carbon is used, the amount of radioactivity exposure is extremely small—less than you normally get from being outside during the day.

Stool antigen test

There are no risks or complications with a stool sample. However, if you do not wash your hands well after collecting the sample, you may spread germs.

Stomach biopsy

There is a slight risk (1 in 10,000) of puncturing the wall of the esophagus, stomach, or duodenum during an endoscopy to collect stomach biopsy samples. The biopsy may also cause some bleeding at the site where the samples are collected. However, the bleeding usually stops without treatment. For more information, see the medical test Upper Gastrointestinal Endoscopy.

After the test

After the test, you may belch and feel bloated for a while. You also may have a tickling, dry throat; slight hoarseness; or a mild sore throat. These symptoms may last several days. Throat lozenges and warm saltwater gargles can help relieve the throat symptoms. Do not drink alcohol after the test.

After the test, contact your doctor immediately if you:

• Vomit blood or notice black or bloody stools.
• Have trouble swallowing or talking.
• Are short of breath or have a fast heartbeat.
• Have increasing chest or abdominal pain.
• Have neck or shoulder pain.
• Have a fever.

Helicobacter pylori tests are used to detect a Helicobacter pylori (H. pylori) infection in the stomach and upper part of the small intestine (duodenum).

Results from the urea breath test or a stool antigen test are generally available within a few hours. Results from a blood antibody test are usually available within 24 hours. Results from biopsy samples obtained by endoscopy are usually available within 48 hours. Results from a biopsy sample that is cultured can take up to 10 days.

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

• The radioactive urea breath test for H. pylori is not usually done during pregnancy or while you are breast-feeding, 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 lansoprazole (Prevacid), rabeprazole (Aciphex), sucralfate (Carafate), omeprazole (Prilosec), famotidine (Pepcid AC), ranitidine (Zantac), nizatidine (Axid), cimetidine (Tagamet), or medicines containing bismuth (such as Pepto-Bismol) can also interfere with the results of the urea breath 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.

• The radioactive urea breath test is not recommended for children or for pregnant or breast-feeding women because of exposure to a small amount of radioactivity.
• The stool antigen test is the newest and 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.
• 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; therefore, the urea breath test or a biopsy may be used to determine if treatment has been effective.
• If your symptoms persist, an endoscopy may be needed. For more information, see the medical test Upper Gastrointestinal Endoscopy.
• Having an infection with H. pylori increases your chances of having cancer of the stomach; but the risk is very low.

Other Works Consulted

• Chernecky CC, Berger BJ, eds. (2004). Laboratory Tests and Diagnostic Procedures, 4th ed. Philadelphia: Saunders.

• Fischbach FT, Dunning MB III, eds. (2004). Manual of Laboratory and Diagnostic Tests, 7th ed. Philadelphia: Lippincott Williams and Wilkins.

• Handbook of Diagnostic Tests (2003). 3rd ed. Philadelphia: Lippincott Williams and Wilkins.

• Pagana KD, Pagana TJ (2002). Mosby’s Manual of Diagnostic and Laboratory Tests, 2nd ed. St. Louis: Mosby.