Synopsis
Choose a test that demonstrates active Helicobacter pylori infection, prepare the patient to avoid false-negative results, select eradication treatment around allergy and antibiotic exposure, and confirm cure when clinically required.
- H. pylori causes chronic active gastritis and is a major driver of duodenal and gastric ulcer, gastric adenocarcinoma and gastric MALT lymphoma.
- Use a carbon-13 urea breath test or validated stool antigen test for uncomplicated non-invasive assessment because each detects current infection rather than remote antibody exposure.
- Stop a proton-pump inhibitor for two weeks before breath or stool testing and avoid antibiotics or bismuth for four weeks where clinically safe to reduce false-negative results.
- Near-patient serology performs inadequately and should not be used; laboratory serology cannot distinguish active from past infection and cannot prove eradication.
- During indicated endoscopy, histology and rapid urease testing can diagnose infection, but biopsy site, recent PPI, bleeding and patchy colonisation affect sensitivity.
- NICE first-line eradication uses a seven-day twice-daily PPI-based combination with two antibiotics, chosen around true penicillin allergy and previous clarithromycin or metronidazole exposure.
- Treatment failure should trigger adherence and exposure review, an alternative regimen and local antimicrobial advice rather than repetition of the same antibiotic pair.
- A test of cure is particularly important after ulcer disease, persistent symptoms, MALT lymphoma or later-line treatment; perform it after the appropriate medicine washout.
Key red flags
Dysphagia, qualifying age–weight-loss combinations, suspicious mass, progressive vomiting or unexplained iron-deficiency anaemia requires appropriate expedited investigation; a stool test must not become a gatekeeper.
Coffee-ground vomiting, melaena, syncope, sudden severe pain or peritonism may represent bleeding or perforation. Stabilise and involve acute services before routine eradication planning.
Investigation priorities
Detect urease activity from current gastric H. pylori non-invasively.
Management branches
Non-invasive H. pylori testing is appropriate and no urgent endoscopic feature supersedes it.
- Check PPI, antibiotic and bismuth use, arrange a two-week PPI washout and four-week antibiotic or bismuth interval when safe, and offer temporary symptom measures that do not invalidate testing.
- Choose carbon-13 breath or validated laboratory stool antigen testing based on availability, patient preference and ability to provide a valid specimen; avoid office antibody kits.
- If stopping acid suppression is unsafe or endoscopy is already indicated, discuss an alternative diagnostic strategy rather than accepting a predictably low-sensitivity result.