Author: Dr Henry Wei. Sources checked 16 October 2026.
Review previous antibiotics and arrange the test of cure
I check previous eradication regimens, macrolide exposure and penicillin allergy before treatment. The plan includes medicine timing before testing and responsibility for reviewing the result.
1. Assess the indication and alarm features
In adults with dyspepsia, assess infection and gastric cancer risk, including country of birth, ethnicity, family history, previous ulcers and NSAID use. Routine paediatric test-and-treat is generally unsuitable.
Dysphagia, bleeding, IDA, weight loss or persistent vomiting may require gastroscopy. Endoscopy can assess complications and obtain samples for culture or susceptibility testing in selected cases.
2. Obtain a reliable active-infection test
Laboratory faecal antigen testing is the usual NZ non-invasive test; a validated breath test is an alternative. Antibiotics and PPIs can interfere with the result, so follow the minimum medicine intervals before sampling.
| Medicine | Minimum interval before the sample |
|---|---|
| PPI | Two weeks without treatment, when clinically safe. |
| Antibiotics | Four weeks, including antibiotics taken for another infection. |
| Bismuth | Four weeks. |
3. Choose treatment and support completion
Review previous antibiotics, allergies, interactions, pregnancy and the ability to complete treatment. NZ guidance includes a 14-day PPI/amoxicillin/clarithromycin regimen for selected patients; bismuth quadruple therapy is an option with previous macrolide exposure, penicillin allergy or persistent infection.
Recent NZ data suggest first-line eradication success is in the order of 80–90% when treatment is completed and cure is checked. Around 10–20% may therefore need a second-line course; bismuth quadruple therapy is a common option, selected using the previous antibiotic history, allergies and current NZ guidance.
Use current prescribing guidance and the linked navigator for regimen details. Provide a dosing schedule and medicine-specific food advice. Mild nausea, loose stools or altered taste are often temporary; intolerance that prevents completion needs prompt review. Incomplete treatment can contribute to failure and resistance.
4. Confirm eradication and review symptoms
Arrange faecal antigen testing four to eight weeks after treatment; six to eight weeks is a practical usual interval. Apply the medicine pauses above even if symptoms have resolved.
For persistent infection, choose an appropriate alternative or seek gastroenterology/microbiology advice. Reusing failed clarithromycin treatment requires a susceptibility-based reason. Persistent symptoms after confirmed eradication may need assessment for reflux, functional dyspepsia or another cause.
Clinical pearls
- Serology can remain positive after eradication; use an active-infection test to confirm cure.
- Persistent infection needs review of adherence, antibiotic history and test timing before another course.
- Gastric ulcers, metaplasia, atrophy or dysplasia may need separate endoscopic follow-up after eradication.
Diagrams for patient discussions
Understand the infection, then check treatment worked
Where is the infection?
H. pylori lives near the surface of the stomach lining. It can cause inflammation and ulcers. Finding it does not mean you have cancer, and it may not explain every symptom.
Where is the infection?
H. pylori lives near the surface of the stomach lining. It can cause inflammation and ulcers. Finding it does not mean you have cancer, and it may not explain every symptom.
What do the tests show?
A stool antigen test or breath test can look for current infection. A blood antibody result can stay positive after the infection has gone. Biopsies during gastroscopy can also be tested when the examination is indicated.
Prepare for a reliable test
Some medicines can suppress the infection enough to give a false negative result. The usual gaps are two weeks after stopping a PPI and four weeks after antibiotics or bismuth, but agree an individual medicine plan before changing treatment.
Check after treatment
Current NZ professional guidance recommends confirming the infection has cleared, even if you feel better. Retesting is generally done 6–8 weeks after finishing treatment, with the PPI preparation agreed beforehand.
Simplified illustrations, not to scale. These show an example, not your own anatomy or test result.
Read every diagram explanation
Where is the infection?
H. pylori lives near the surface of the stomach lining. It can cause inflammation and ulcers. Finding it does not mean you have cancer, and it may not explain every symptom.
What do the tests show?
A stool antigen test or breath test can look for current infection. A blood antibody result can stay positive after the infection has gone. Biopsies during gastroscopy can also be tested when the examination is indicated.
Prepare for a reliable test
Some medicines can suppress the infection enough to give a false negative result. The usual gaps are two weeks after stopping a PPI and four weeks after antibiotics or bismuth, but agree an individual medicine plan before changing treatment.
Check after treatment
Current NZ professional guidance recommends confirming the infection has cleared, even if you feel better. Retesting is generally done 6–8 weeks after finishing treatment, with the PPI preparation agreed beforehand.
Information to share with your patient
Related clinician articles
References
- bpacnz: H. pylori, updated 27 August 2026
- bpacnz: antibiotic guide, updated August 2026
- ACG: H. pylori guideline highlights, 2024
- Maastricht VI/Florence consensus, 2022
- Inns et al.: NZ clarithromycin-resistance study, 2025
- AGA: refractory H. pylori expert review, 2021
- NICE CG184: dyspepsia assessment and testing