How to assess for eradication of H. pylori (Helicobacter pylori) after treatment?

Assessing H. pylori Eradication After Treatment

The urea breath test (UBT) is the gold standard non-invasive test for confirming H. pylori eradication and should be performed no earlier than 4 weeks after completion of treatment. 1

Testing Methods for H. pylori Eradication

Endoscopy-Based Testing

• Indicated for:
  • Complicated peptic ulcer disease
  • Gastric ulcer (to exclude malignancy)
  • MALT lymphoma
  • When treatment has low efficacy or poor compliance 2
• Procedure:
  • Obtain full-thickness mucosal biopsy specimens:
    • Two specimens from the antrum
    • Two specimens from the body
    • One additional specimen for rapid urease test 2
  • Multiple targeted biopsies may be needed for mucosal abnormalities

Non-Invasive Testing

• Urea Breath Test (UBT):

  • Sensitivity: 94.7%, Specificity: 95.7% 2
  • Available in two forms:
    • 13C-UBT (non-radioactive, safe for children and pregnant women)
    • 14C-UBT (contains radioactive isotope, avoid in children and pregnant women) 2

• Stool Antigen Test:

  • Sensitivity: 88.8-92.1%, Specificity: 87.3-87.6% in post-treatment setting 2
  • Viable alternative to UBT according to European Helicobacter Study Group 2
  • Comparable to UBT for initial diagnosis but slightly less accurate post-treatment

• Serology:

  • Not recommended for confirming eradication
  • Requires 50% fall in antibody titers
  • Takes up to 6 months to show changes
  • Requires validated test kit and simultaneous measurement of samples 2

Timing of Post-Treatment Testing

• Optimal timing: No earlier than 4 weeks after completion of treatment 2, 1
• Studies show that H. pylori status at 1 month post-treatment accurately reflects successful eradication (93% agreement with 6-month testing) 3

Patient-Specific Recommendations

Testing is Strongly Recommended for:

• Complicated peptic ulcer disease
• Gastric ulcer
• MALT lymphoma
• Cases where treatment had low efficacy
• Patients with poor compliance 2

Testing May Not Be Necessary When:

• Symptoms resolve in uncomplicated duodenal ulcer or non-ulcer dyspepsia
• In duodenal ulcer, symptom assessment at 3 and 6 months can be as valuable as UBT 2

Important Considerations and Pitfalls

• Medication interference:

  • Discontinue proton pump inhibitors (PPIs), antibiotics, and bismuth products at least 2 weeks before testing to avoid false negatives 1
  • Recent studies suggest that citrate administration may decrease false-negative results in patients taking PPIs, but more research is needed 2

• False positives can occur in:

  • Achlorhydria
  • Pernicious anemia
  • Atrophic gastritis
  • Overgrowth of non-H. pylori urease-producing organisms 1

• Treatment failure:

  • If eradication fails, re-treatment should avoid antibiotics used previously
  • Consider culture and sensitivity testing to guide appropriate antimicrobial therapy 2
  • The American College of Gastroenterology now recommends bismuth quadruple therapy for 14 days as the preferred regimen when antibiotic susceptibility is unknown 4

Algorithm for Post-Treatment Assessment

1. Wait at least 4 weeks after completion of treatment
2. Discontinue PPIs, antibiotics, and bismuth products 2 weeks before testing
3. Select appropriate test based on patient characteristics:
   • For complicated cases (gastric ulcer, MALT lymphoma): Endoscopy with multiple biopsies
   • For uncomplicated cases: UBT (preferred) or stool antigen test
4. If eradication fails, consider culture and sensitivity testing before retreatment