H. Pylori Symptoms and Diagnostic Testing
Clinical Presentation
Most H. pylori infections are asymptomatic, but when symptoms occur, they typically manifest as dyspepsia (epigastric pain or discomfort), which cannot reliably distinguish H. pylori infection from other causes without laboratory confirmation. 1, 2
Symptoms Requiring Evaluation
- Epigastric pain or discomfort (dyspepsia) is the most common presenting symptom 3
- Alarm symptoms requiring immediate endoscopy include: bleeding (hematemesis or melena), unintentional weight loss, progressive dysphagia, recurrent vomiting, palpable abdominal mass, and anemia 4, 3
- Patients may present with complications such as peptic ulcer disease (gastric or duodenal ulcers), which occurs in a subset of infected individuals 2, 5
Diagnostic Strategy: Age-Based Algorithm
For Patients Under 50-55 Years Without Alarm Symptoms
Use the "test and treat" strategy with non-invasive testing first—this reduces unnecessary endoscopies by 62% while maintaining equivalent safety. 4, 6
Preferred Non-Invasive Tests (First-Line)
- Urea Breath Test (UBT): Most accurate non-invasive test with sensitivity of 94.7-97% and specificity of 95-95.7% 4
- Stool Antigen Test: Laboratory-based monoclonal antibody test with sensitivity and specificity of 93%, comparable to UBT 4, 6
- Both tests detect active infection only, making them valuable for initial diagnosis and post-treatment confirmation 4
Critical Testing Requirements
- Stop proton pump inhibitors (PPIs) for at least 2 weeks before testing to avoid 10-40% false-negative rates 4, 7
- Stop antibiotics and bismuth for at least 4 weeks before testing 7, 4
- Histamine-2 receptor antagonists can be substituted for PPIs during the washout period as they do not affect bacterial load 7
For Patients Over 50 Years or With Alarm Symptoms
Proceed directly to endoscopy with invasive testing due to increased malignancy risk. 4, 6
Invasive Tests During Endoscopy
- Rapid Urease Test: Provides quick results during endoscopy 4
- Histology: Requires at least two biopsy samples from antrum and body, allows visualization of bacteria and assessment of mucosal damage 4
- Culture with susceptibility testing: Provides definitive proof and antimicrobial resistance patterns, particularly valuable after treatment failure or in regions with high clarithromycin resistance (>15-20%) 4
- PCR: Can detect H. pylori and antibiotic resistance directly from biopsies 4
Serology: Limited Role
Serology should NOT be used as the primary diagnostic method and cannot confirm eradication after treatment. 4, 6
Why Serology Is Problematic
- Cannot distinguish between active infection and past exposure—antibodies persist long after eradication (creates a "serologic scar") 7, 4
- Overall accuracy averages only 78% (range 68-82%), inadequate for clinical use 4
- Positive predictive value falls dramatically in low-prevalence populations 4
Limited Acceptable Uses for Serology
- When patients cannot stop PPIs, antibiotics, or bismuth and clinical suspicion is very high 4
- In patients with gastric atrophy, gastric malignancies, or active ulcer bleeding where other tests may be falsely negative 4
- Important caveat: If serology is used, confirm positive results with UBT or stool antigen test before starting treatment 7
Post-Treatment Confirmation (Test of Cure)
Always perform test of cure at least 4 weeks after completing eradication therapy using UBT or stool antigen test—never use serology. 7, 6, 3
Test of Cure Protocol
- Timing: Perform at least 4-6 weeks after treatment completion 4, 3
- Preferred tests: UBT (sensitivity 91.6%, specificity 98.4%) or laboratory-based monoclonal stool antigen test 6
- Same medication washout periods apply: PPIs stopped 2 weeks, antibiotics/bismuth stopped 4 weeks 4
Common Pitfalls to Avoid
- Rapid in-office serological tests have limited accuracy and should be avoided—only laboratory-based validated tests are acceptable 4
- Using IgA and IgM antibody panels provides no added benefit over validated IgG tests and often includes non-FDA-approved tests of unclear value 7
- False positive UBTs can occur in achlorhydria (e.g., pernicious anemia, atrophic gastritis) due to urease-producing non-H. pylori organisms—confirm with stool antigen test or endoscopy before retreatment 7
- Failure to stop PPIs before testing is the most common cause of false-negative results in all tests except serology 4