When should a test of cure be performed on a patient who has completed Helicobacter pylori (H. pylori) treatment as ordered, and would another stool antigen test be appropriate?

Test of Cure After H. pylori Treatment

Perform a test of cure at least 4 weeks after completing H. pylori treatment using either a urea breath test or a validated monoclonal stool antigen test—yes, another stool test is appropriate and highly accurate for this purpose. 1, 2

Timing Requirements

Wait a minimum of 4 weeks after treatment completion before testing. This waiting period is critical because:

• The gastric mucosa requires at least 4 weeks to recover from treatment effects 1, 2
• Testing before 4 weeks yields false-negative results due to temporary bacterial suppression rather than true eradication 1, 2
• In cases of bleeding peptic ulcers specifically, testing may be delayed to 4-8 weeks after the bleeding episode 1, 2

Recommended Testing Methods

Use non-invasive testing for most patients:

• Stool antigen test: A laboratory-based validated monoclonal stool antigen test has sensitivity and specificity >90% and is an excellent choice 1, 2
• Urea breath test (UBT): The gold standard with sensitivity of 94.7-97% and specificity of 95-100% 1, 2
• Both tests are equally accurate and can be used interchangeably 3, 1

Endoscopy with biopsy is reserved for specific high-risk scenarios:

• Gastric ulcer (to confirm healing and exclude malignancy) 3, 2
• Complicated peptic ulcer disease 3, 2
• Gastric MALT lymphoma 3, 2

Critical Pre-Testing Requirements

Medication washout is mandatory to avoid false-negative results:

• Stop proton pump inhibitors (PPIs) for at least 2 weeks, preferably 7-14 days 1, 2
• Discontinue antibiotics and bismuth for at least 4 weeks 3, 1, 2
• Patients should fast for at least 6 hours before testing 3

Why Test of Cure is Essential

Confirmation of eradication is now considered standard of care for all patients. 1 The rationale includes:

• Provides indirect measure of antibiotic resistance patterns in the population 1
• Persistent infection is a negative prognostic marker for ulcer recurrence and complications 3, 1
• Non-recurrence of ulcers is strictly dependent on successful H. pylori eradication 3

Common Pitfalls to Avoid

Do not use serology for test of cure—antibody levels remain elevated after eradication, making serology useless for confirming cure. 3, 1, 2

Do not test too early—results before 4 weeks are unreliable and will lead to inappropriate management decisions. 1, 2

Do not skip PPI washout—inadequate washout causes false-negative results, potentially missing treatment failure. 1, 2

Management Based on Results

If eradication is confirmed:

• Discontinue PPI in uncomplicated duodenal ulcer patients 2
• Continue PPI in gastric ulcer patients until complete healing is confirmed 2

If H. pylori persists:

• Use a completely different antibiotic regimen, avoiding previously used antibiotics 1, 2
• Consider 14-day levofloxacin triple therapy or 14-day bismuth quadruple therapy if not previously used 1, 2
• After two treatment failures, pursue antibiotic susceptibility testing to guide third-line therapy 1, 2, 4