When is H. pylori (Helicobacter pylori) testing indicated?

Indications for H. pylori Testing

H. pylori testing is strongly indicated for patients with peptic ulcer disease (gastric or duodenal), gastric MALT lymphoma, following endoscopic resection of early gastric cancer, and in patients with unexplained iron deficiency anemia or idiopathic thrombocytopenic purpura. 1, 2

Primary Indications for Testing

• Active peptic ulcer disease (gastric or duodenal)
• History of peptic ulcer (not previously treated for H. pylori)
• Gastric MALT lymphoma
• Following endoscopic resection of early gastric cancer
• Uninvestigated dyspepsia in patients <50 years without alarm symptoms (test-and-treat strategy)
• Unexplained iron deficiency anemia
• Idiopathic thrombocytopenic purpura (ITP)
• Long-term PPI users to prevent progression to atrophic gastritis
• Before starting long-term NSAID therapy (especially in patients with history of peptic ulcer)
• First-degree relatives of patients with gastric cancer

Secondary Indications

• Vitamin B12 deficiency without other identified causes
• Patients taking medications with impaired absorption due to H. pylori (e.g., thyroxine, l-dopa)
• Atrophic gastritis
• Corpus-predominant gastritis

Testing in Special Populations

• Immigrants from high-prevalence regions
• Individuals with family history of gastric cancer
• Patients with persistent dyspeptic symptoms despite appropriate therapy

Testing Methods

1. Non-invasive tests (no endoscopy required):

   • 13C-Urea Breath Test (UBT): Sensitivity 95%, Specificity 95% - preferred non-invasive test 2
   • Stool Antigen Test (SAT): Sensitivity 88-90%, Specificity 91-100% 2
   • Serology (ELISA): Sensitivity 90%, Specificity 95% - useful when patients are on PPIs 1, 2

2. Invasive tests (require endoscopy):

   • Rapid urease test
   • Histology (biopsies from both antrum and body)
   • Culture (for antibiotic susceptibility testing)

Important Testing Considerations

• Stop PPI therapy 2 weeks before testing for all methods except serology 1
• Antibiotics should be discontinued 4 weeks before testing 1
• H2-receptor antagonists have less impact on test accuracy but ideally should be stopped 24-48 hours before testing 1
• Serology is the only test not affected by recent antibiotic use or PPI therapy 1

Post-Treatment Testing

• Confirm eradication at least 4 weeks after completion of therapy 1
• UBT or SAT are recommended for confirmation (not serology) 1
• Endoscopy-based testing is necessary for:
  • Complicated peptic ulcer disease
  • Gastric ulcers (to exclude malignancy)
  • MALT lymphoma
  • When histological assessment of mucosal abnormalities is needed 1

Common Pitfalls to Avoid

• Not stopping PPIs before testing (leads to false negatives)
• Testing too soon after antibiotics (leads to false negatives)
• Using serology for post-treatment confirmation (antibodies persist for months)
• Inadequate biopsy sampling (should include both antrum and body)
• Overlooking H. pylori infection in patients with gastritis 2
• Missing associated nutritional deficiencies (iron, B12) 2

H. pylori testing is a critical component in the management of various gastrointestinal conditions, with significant implications for reducing morbidity and mortality related to peptic ulcer disease and gastric cancer. The appropriate selection of testing method and timing is essential for accurate diagnosis and effective management.