Specialty Testing Guide › GI-MAP Gut Testing
H. pylori (Helicobacter pylori) is a bacterium that lives in the lining of the stomach. It can cause upper belly pain, bloating, nausea and feeling full too soon, and it is a common cause of stomach ulcers and a known cause of stomach cancer, though many people who carry it never know.
Because the infection is common and treatable, guidelines name specific groups who should be tested, even without symptoms. Anyone who tests positive should be treated and then retested to make sure the treatment worked.
Key takeaways
- More than half the people in the world carry H. pylori, and in North America the figure is roughly a third.
- It can cause indigestion and ulcers, and it raises the long-term risk of stomach cancer.
- US guidelines now recommend testing adults who share a home with someone who has it, along with other higher-risk groups.
- After treatment, a repeat breath, stool or biopsy test is needed to confirm the infection has cleared.
What H. pylori is and how common it is
H. pylori is a spiral-shaped bacterium adapted to survive stomach acid. It settles into the stomach lining, where it can cause long-lasting inflammation called gastritis.
A large review estimated that about 4.4 billion people worldwide had H. pylori in 2015, more than half the world's population.1 Rates vary widely by country, from under 20% in some to more than 80% in others. The American College of Gastroenterology puts prevalence in North America at 30% to 40%, with the infection typically picked up in childhood.2
How it spreads
Researchers are still working out exactly how H. pylori passes between people. The bacteria may spread from person to person through contact with an infected person's vomit, stool or saliva, or through food or water contaminated by them.3
Infection is more common in crowded living conditions, in places with poor sanitation and among people who moved from regions where it is widespread.
Symptoms
H. pylori usually does not cause symptoms.4 When it does cause trouble, usually through gastritis or an ulcer, symptoms can include:
- Pain or discomfort in the upper belly, between the belly button and breastbone
- Feeling full too soon, or uncomfortably full after a meal
- Nausea or vomiting
- Bloating and belching
These symptoms overlap with heartburn, gallbladder trouble and functional dyspepsia, so they do not prove H. pylori on their own. Testing is the only way to know.
Get medical help right away for black or tarry stools, red or maroon blood in your stool, vomit that looks like coffee grounds, sudden severe belly pain, or feeling dizzy or faint. These can signal a serious ulcer complication. Call 911 if symptoms are severe.
Ulcer and stomach cancer risk
H. pylori and anti-inflammatory pain relievers such as aspirin, ibuprofen and naproxen are the two most common causes of peptic ulcers.
The World Health Organization classifies H. pylori as a group 1, or definite, carcinogen.2 Most people with the infection will never develop stomach cancer, but the risk is real. In randomized trials, mostly in Asia, treating H. pylori in healthy infected adults cut later stomach cancer cases by nearly half.5
Who should be tested
The 2024 American College of Gastroenterology guideline lists these groups among those who should be tested:
- People with indigestion (dyspepsia), especially under 60 without alarm features
- Anyone with a current or past peptic ulcer
- People taking anti-inflammatory pain relievers long term or starting daily aspirin
- People with iron deficiency anemia that has no other explanation, or immune thrombocytopenia (a low platelet count)
- Adult household members of someone who tests positive
- People with a family history of stomach cancer, or who emigrated from a region where stomach cancer is common
- People with certain precancerous stomach changes or MALT lymphoma
How it is tested and treated
Standard tests that show a current infection are the urea breath test, the stool antigen test and, during an upper endoscopy, a biopsy. Acid-reducing medicines, bismuth and recent antibiotics can cause false negatives. Before a follow-up test, the ACG advises holding proton pump inhibitors for two weeks and bismuth and antibiotics for four weeks, so ask your doctor before stopping anything.2
Treatment combines several medicines, usually for 14 days, chosen with antibiotic resistance in mind. A follow-up breath, stool or biopsy test is advised at least four weeks after therapy to confirm the infection is gone.62
Some DNA stool panels also report H. pylori. A positive result on that kind of test should be confirmed and treated according to these guidelines. Our guide to H. pylori on a GI-MAP explains how that result compares with standard tests.
Your next step
If you fit one of the groups above or have ongoing upper belly symptoms, ask your primary care doctor about a breath or stool antigen test. Both are widely available across Pennsylvania. If you have alarm symptoms, ask about seeing a gastroenterologist.
To learn more about how DNA stool testing works and where it fits beside standard tests, read how DNA stool testing works or visit the gut testing hub.
Frequently asked questions
Can H. pylori go away on its own?
Do not count on it. Current US guidelines say that everyone found to be infected should be treated, rather than waiting to see whether it clears.
Should my partner or family be tested if I have it?
The 2024 ACG guideline recommends testing adult household members of people who test positive. Talk with your doctor about who in your home should be checked.
Can I be reinfected after treatment?
It is possible. Confirming that treatment worked, and testing adults you live with, both lower the chance of the infection coming back unnoticed.
Related reading
This article is for general education and is not medical advice. Decisions about testing and treatment should be made with your clinician. If you have severe symptoms, call 911. For a suspected poisoning, call Poison Control at 1-800-222-1222.
