Version July 2025
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What is H. pylori? —
This is a type of bacteria. It can cause a stomach infection that can lead to ulcers.
Doctors can do different tests to diagnose H. pylori infection. These include:
●Breath tests – These measure substances in a person's breath after they drink a special liquid. They are also called "urea breath tests."
●Stool tests – These are tests on a sample of a bowel movement, or "stool."
●Biopsy – A doctor takes a small piece of tissue from the lining of the stomach. Then, they look at the tissue under a microscope. They can do a biopsy during an endoscopy. This is a procedure that lets a doctor look at the inside lining of the esophagus, stomach, and duodenum. (The duodenum is the first part of the small intestine.)
●Blood test – This is not as accurate as the other tests, so it is not often used.
Your doctor will choose a test based on your situation. If you already need to get an endoscopy, the doctor will probably do a biopsy. If not, they might do a breath or stool test instead.
How do I prepare for an H. pylori test? —
Your doctor or nurse will tell you what you need to do to prepare. If you are having a breath test or biopsy, you will need to avoid eating or drinking for a few hours before the test.
Some medicines need to be stopped 2 to 4 weeks before the test. These include:
●Medicines to reduce the amount of acid that the stomach makes
●Bismuth subsalicylate (brand name: Pepto-Bismol)
●Antibiotics
It's important to follow all instructions about stopping medicines. If you don't, the test results might not be accurate.
What happens during an H. pylori test? —
It depends on which test you get:
●Breath test – You breathe out into a balloon or bag before and after drinking a special liquid. The doctor measures how much carbon dioxide you breathed out. This can tell them if you have H. pylori in your body. The test takes about 15 to 30 minutes.
●Stool test – You collect a sample of your bowel movement. You can do this at home using a special collection kit. Your doctor will tell you where and when to send the sample. Then, the sample is tested for H. pylori in a lab.
●Biopsy – This is done during an upper endoscopy. A doctor puts a thin tube down your throat and into your stomach. The tube has a light and a tiny camera on the end, so the doctor can see inside your stomach. They take a small sample from the lining of your stomach and look at it under a microscope.
●Blood test – You get a blood draw. Then, your blood is tested for "antibodies." These are proteins that the body makes when you have an H. pylori infection.
What do my results mean? —
Your doctor or nurse will tell you when to expect your results, and will contact you with the results. Or if you use an online "patient portal," you might get an alert there when your results are ready.
The results can be:
●Positive – A positive breath test, stool test, or biopsy means that you have H. pylori infection. A positive blood test can mean that you have H. pylori infection or that you had it in the past. This is because antibodies stay in the blood even after the infection has been cured.
●Negative – A negative result for any of these tests means that you probably do not have H. pylori infection.
If you do have an infection, your doctor will talk to you about treatment.
Patient education: H. pylori infection (The Basics)
Patient education: Upper endoscopy (The Basics)
Patient education: Peptic ulcers (The Basics)
Patient education: Stomach polyps (The Basics)
Patient education: Low iron (The Basics)
Patient education: Nausea and vomiting in adults (The Basics)
Patient education: Helicobacter pylori infection and treatment (Beyond the Basics)
Patient education: Upper endoscopy (Beyond the Basics)
Patient education: Peptic ulcer disease (Beyond the Basics)
Patient education: Anemia caused by low iron in adults (Beyond the Basics)
