In shortH. pylori is checked four ways: the breath test and stool antigen show current infection, blood antibodies show a past or present encounter (they persist after cure), and endoscopic biopsy is the most accurate. After treatment, control is by breath test or stool antigen in 4–6 weeks.
About the infection
Helicobacter pylori is a bacterium colonizing the stomach lining. A large share of adults carry it, mostly without trouble, but it is the main cause of chronic gastritis, stomach and duodenal ulcers and a risk factor for stomach cancer.
Treating H. pylori is not always needed — a gastroenterologist decides. So the tests’ job is to answer precisely “is the bacterium there now”, and the methods differ in value for that.
Diagnostic methods
| Method | What it shows | When it is used |
|---|---|---|
| Urea breath test (¹³C) | Current infection: the bacterium splits urea, the isotope shows in exhaled air | Initial diagnosis and cure control; accuracy about 95% |
| Stool H. pylori antigen | Bacterial proteins in stool — whether infection is present now | Initial diagnosis and post-treatment control; convenient for children |
| IgG antibodies in blood | A past or present encounter with the bacterium | Screening; unfit for cure control — antibodies persist for years |
| Endoscopic biopsy (rapid urease, histology) | The bacterium and the lining under a microscope | When endoscopy is indicated; the most accurate method |
How to prepare
For the breath test and stool antigen: proton pump inhibitors (omeprazole and similar) are stopped 2 weeks before, antibiotics and bismuth 4 weeks before (agreed with the doctor). The breath test is taken fasting. Blood antibody testing needs no preparation.
Reading the result
| Result | What it means |
|---|---|
| Breath test / stool antigen “positive” | The bacterium is in the stomach now — discuss treatment with a gastroenterologist |
| Breath test / stool antigen “negative” | No active infection (with proper preparation) |
| IgG antibodies “positive” | An encounter happened — current infection is confirmed by breath test or stool antigen |
| Antibodies after treatment | Not used: they stay positive for months and years |
When a retest makes sense
Cure control — no earlier than 4–6 weeks after therapy ends, by breath test or stool antigen. Antibodies are not used for control.
Which specialist to see
A positive or doubtful result is reviewed by: Gastroenterologist, primary care physician. Note the date of the first test and the possible contact — the retesting plan depends on it.
Several markers on your report?
The app reads your whole report — this marker together with its neighbors, not one by one.
Frequently asked questions
Which H. pylori test is the most accurate?
Among non-invasive ones — the breath test and stool antigen (about 90–95% accurate with proper preparation). The most accurate overall is biopsy histology during endoscopy, but endoscopy is not done for everyone.
Antibodies are positive — do I need treatment?
Not necessarily. Antibodies only mark an encounter — it may be long past and cleared. The decision uses a current-infection test (breath or stool) plus complaints and endoscopy data if available.
Why stop omeprazole before the breath test?
Proton pump inhibitors suppress the bacterium’s activity and the test can turn falsely negative. They are stopped 2 weeks ahead, antibiotics and bismuth 4 weeks — agreed with the prescribing doctor.
Sources
- MedlinePlus — Helicobacter pylori tests — MedlinePlus (medlineplus.gov). Accessed: September 17, 2026.
- MSD Manuals — Helminths — MSD Manuals (msdmanuals.com). Accessed: September 17, 2026.