Short answer
H. pylori is a bacterium linked to peptic ulcers, gastritis, and a higher long-term stomach cancer risk in some people. The important question is usually not just “is there H. pylori?” but “which test will best answer this question: active infection, ulcer evaluation, or proof that treatment worked?” Breath and stool tests are used for active infection and test-of-cure; blood antibody tests are much less useful because they can stay positive long after the infection is gone.
Test types
| Test | Best use | Main caveat |
|---|---|---|
| Urea breath test | Active infection and test-of-cure. | PPIs, antibiotics, and bismuth can suppress the bacteria and create a false negative if not held. |
| Stool antigen test | Active infection and test-of-cure. | Recent medicines and collection timing matter. |
| Blood antibody test | Exposure history only. | Antibodies may remain positive for years, so it does not reliably show current infection or cure. |
| Endoscopy biopsy | Alarm symptoms, bleeding, ulcers, or direct stomach evaluation. | More invasive, but lets clinicians look at the lining and biopsy tissue. |
Who should be tested
ACG guidance supports testing in several common situations: unexplained dyspepsia in many adults without alarm features, current or prior peptic ulcer disease, chronic NSAID or daily aspirin use, unexplained iron deficiency anemia, idiopathic thrombocytopenic purpura, and some higher-risk stomach-cancer settings. If the clinician already wants an endoscopy, biopsies can also check for H. pylori at the same time.
How to prep
- Ask whether you should stop PPIs, antibiotics, or bismuth before the test.
- If the plan is test-of-cure, the usual window is at least 4 weeks after antibiotics are finished.
- For test-of-cure, PPIs are usually held for 1 to 2 weeks so they do not suppress the bacteria.
- For endoscopy, fasting is typically required and someone should bring you home afterward.
What results mean
- A positive breath or stool test usually means active infection is present.
- A negative breath or stool test lowers the chance of active infection, but timing and medicines still matter.
- A positive blood antibody test only means exposure at some point in the past or present.
- A blood antibody test is not the right tool to prove cure.
Test-of-cure
When treatment is finished, guidelines recommend confirming eradication with a breath test, stool antigen test, or biopsy-based test. NIDDK and ACG both point to waiting at least 4 weeks after antibiotics end and holding PPIs for about 1 to 2 weeks before the follow-up test. That timing matters because an early test can look falsely reassuring.
Related guides: stool test vs microbiome test, fecal calprotectin test, celiac disease blood tests, and lactose intolerance breath test.
FAQ
Which H. pylori test is best?
For active infection, the breath test and stool antigen test are usually the main noninvasive choices. Blood antibody tests are much less useful for current infection.
Can blood tests tell if H. pylori is gone?
No. Blood antibody tests can stay positive after the infection has cleared, so they are not used to prove cure.
How long should I stop acid suppressors before testing?
Ask the ordering clinician, but PPIs are commonly held for 1 to 2 weeks before a test-of-cure, and antibiotics or bismuth may also need to be stopped earlier.
Why would a doctor choose endoscopy instead of a breath or stool test?
Endoscopy is more useful when there are alarm symptoms, bleeding, ulcer concerns, or a need to directly inspect and biopsy the stomach lining.
When should I repeat testing after treatment?
Usually at least 4 weeks after antibiotics are finished, with PPIs held long enough that the bacteria are not artificially suppressed.
Do symptoms alone prove H. pylori?
No. Dyspepsia, reflux, nausea, or bloating can have many causes, so test choice and follow-up matter.