What are helicobacter pylori (H. pylori) tests?

Helicobacter pylori (H. pylori) is a common type of bacteria that infects the lining of the stomach and the first part of the small intestine. Most people with H. pylori never have symptoms. But in some people, the bacteria can cause problems with digestion.

H. pylori is the most common cause of peptic ulcers, which are sores that form mainly in the stomach and upper part of the small intestine. H. pylori can also cause gastritis (inflammation and irritation of the stomach lining). Without treatment, H. pylori gastritis can last a lifetime and increase the chance of developing stomach cancer.

Researchers aren't sure how people get the bacteria. H. pylori may be spread from person to person through contact with vomit, stool (poop), or saliva (spit) from an infected person. The bacteria may also be spread through contaminated food and water.

Anyone who is exposed to H. pylori can become sick with an H. pylori infection. But H. pylori infections are most common in children. Testing for the bacteria can find out if H. pylori is causing gastritis or other conditions that cause ongoing indigestion. If so, treatment can kill the bacteria so the lining of your stomach can heal.

There are different ways to test for an H. pylori infection. The most common tests use samples of your breath or stool. In certain cases, tests are done on a sample of tissue that's removed from inside your stomach.

Other names: H. pylori stool antigen, H. pylori breath tests, urea breath test, rapid urease test (RUT) for H. pylori, H. pylori culture

What are they used for?

H. pylori tests are used to:

• Find out if an H. pylori infection is the cause of digestive symptoms
• Find out if treatment has cured an H. pylori infection

Because there are many possible causes of digestive symptoms, providers often order tests for other digestive disorders along with an H. pylori test.

Why do I need an H. pylori test?

You may need an H. pylori test if you have symptoms of gastritis or an ulcer. These conditions are often caused by H. pylori bacteria. The symptoms may include:

• Pain in your upper abdomen (belly)
• Bloating (a feeling of fullness or swelling in your belly)
• Feeling full too soon while eating a meal
• Nausea and vomiting
• Burping or belching
• Loss of appetite
• Weight loss

Gastritis can lead to an ulcer, which is a more serious condition. The symptoms of an ulcer can become severe if you develop complications. Get medical help right away if you have:

• Signs of stomach bleeding which include:
  • Black or tarry stool
  • Red blood in vomit or vomit that looks like coffee grounds
• Sudden, sharp or severe belly pain that doesn't go away
• Dizziness or fainting
• A rapid pulse (heartbeat) or other symptoms of shock
• A chance or worsening in your symptoms if you already know you have an ulcer

If you've been treated for an H. pylori infection, you may need testing to see if treatment worked to get rid of all the bacteria. If H. pylori remains in your body, it can grow and cause symptoms again.

What happens during H. pylori testing?

There are different ways to test for H. pylori. Your health care provider may order one or more tests:

A breath test is also called a urea breath test. It generally includes these steps:

• First, you will breathe into a container to provide a sample of your breath.
• Next you will swallow a pill or liquid that contains urea. Urea is a normal waste product found in blood. The urea used for the test contains special carbon atoms. If you have H. pylori, the bacteria will change the urea into carbon dioxide that includes these carbon atoms. Your body will get rid of the carbon dioxide in the air you exhale (breathe out).
• A few minutes after swallowing the urea, you'll provide another sample of your breath.
• The two breath samples will be tested and compared to each other. If you have H. pylori bacteria in your stomach:
  • The special carbon atoms in the urea will show up in the second sample of your breath.
  • The second breath sample will contain more carbon dioxide than the first.

Stool tests. There are different ways to check a stool sample for H. pylori:

• Antigen tests are the most common type of test for H. pylori. Antigens are a type of protein. The test checks your sample for antigens that come from H. pylori.
• PCR tests check your sample for genetic material from H. pylori.

Your provider will probably give you a container or kit with instructions on how to collect a stool sample. There are different ways to collect the sample so follow the instructions carefully. In general, you'll need to:

• Label the container with your name, the collection date, and time.
• Collect a stool sample as instructed. This usually involves using a clean, dry container, or special paper or plastic wrap placed over the toilet to catch the stool.
• Make sure the stool doesn't mix with any urine, toilet paper, or water from the toilet.
• Close the container tightly.
• Wash your hands well with soap and water.
• Return the container according to the instructions.

If you're collecting a sample from diapers, you'll get special instructions for using plastic wrap inside of a clean diaper. In certain cases, a provider may use a swab to take a stool sample from the rectum.

Endoscopy. If other tests don't provide enough information for a diagnosis, your provider may order a procedure called an endoscopy. Your provider will use a scope to look at your esophagus (the tube that links your mouth and stomach), the lining of your stomach, and part of your small intestine. During the procedure:

• You will lie down on an exam table.
• You'll be given medicine to help you relax and to numb your throat so you won't feel pain.
• Your provider will insert a thin tube (an endoscope) through your mouth and into your stomach. The tube has a light and camera to let your provider examine you.
• Your provider may take a biopsy to remove small samples of tissue. The tissue will be sent to a lab to test for H. pylori and other conditions that may be causing symptoms.
• After the procedure, you'll recover for an hour or two while the medicine wears off.

Will I need to do anything to prepare for testing?

Before you have an H. pylori test, you may need to stop taking certain medicines for two weeks to a month. This includes many medicines you may be taking for your symptoms. Be sure to talk with your provider about all medicines you are currently taking.

For an endoscopy, you may need to fast (not eat or drink) for several hours before the procedure. You may be drowsy afterwards, so plan to have someone bring you home.

Are there any risks to testing?

There is no known risk to having breath or stool tests.

During an endoscopy, you may feel some discomfort when the scope is inserted, but serious complications are rare. There's a very small risk of a tear in your intestine. If you have a biopsy, there's a small risk of bleeding where the sample was removed. But it usually stops on its own.

What do the results mean?

A negative (normal) H. pylori test result means that you probably don't have an H. pylori infection. Your provider may order more tests to find out the cause of your symptoms.

A positive test result means that you have an H. pylori infection. Your provider will usually prescribe one or more antibiotics to treat the infection. You will usually take other medicines to relieve your symptoms and help heal your stomach. After you finish your treatment, your provider may order repeat tests to make sure all the H. pylori bacteria is gone.

Learn more about laboratory tests, reference ranges, and understanding results.

Is there anything else I need to know about H. pylori testing?

Blood tests for H. pylori check for certain proteins (antibodies) that your immune system makes to fight off H. pylori. These tests aren't commonly used to diagnose H. pylori. That's because the test can't show whether the antibodies are from an active H. pylori infection that you have now or a past infection that your antibodies successfully fought off.

But if an H. pylori blood test shows that you don't have any H. pylori antibodies, it usually means that you didn't have an infection when your blood sample was taken.