Helicobacter pylori can be investigated using a stool sample or a breath test, among other methods. The appropriate test depends on the reason for investigation and whether this is an initial assessment or a check after treatment.
What is the test looking for?
H. pylori is a bacterium that can live in the stomach and cause ulcers. Abdominal discomfort or heartburn alone cannot identify it. Discuss a positive result with a clinician, who can decide on treatment and follow-up.
A blood antibody test answers a different question from tests aimed at detecting current infection. Keep the exact test name when comparing old and new results.
Different tests have different roles
| Method | Useful question |
|---|---|
| Stool antigen test | Is this appropriate before or after treatment in my case? |
| Breath test | What preparation does this clinic require? |
| Sample during gastroscopy | Is gastroscopy needed for another reason too? |
| Blood antibodies | Does this result need confirmation with another method? |
Acid suppression and antibiotics can affect results
Proton pump inhibitors such as omeprazole and antibiotics can cause a falsely negative stool antigen result. Karolinska’s laboratory guidance specifies at least two weeks after stopping a proton pump inhibitor and four weeks after antibiotics. This laboratory instruction is not advice to stop treatment yourself.
Ask the ordering clinician to plan any interruption safely, including how to manage symptoms. Record the last dose and tell the clinic if you need to restart the medicine. Follow the instructions for your particular test.
Your preparation and follow-up checklist
- Which test is ordered and what decision will it help make?
- Have medicines that affect the result been reviewed?
- Where should I deliver the sample and how will I receive the result?
- If treated, when and how will treatment success be checked?
When a routine test is not enough
Seek emergency assessment for vomiting blood or black, tarry stool, especially with dizziness or weakness. Contact a vårdcentral, a primary care centre, about swallowing difficulty, unexplained weight loss or persistent symptoms. Call 1177 for advice. Warning symptoms should not wait for a self-ordered bacterial test.
Sources and further reading
Sources and links checked on 22 October 2026. Editorial team: Hagakliniken. General information; individual assessment may differ.