Why is the H. pylori (Helicobacter pylori) test recommended?

Why Perform H. pylori Testing

H. pylori testing is recommended to identify active infection in patients with specific clinical conditions where eradication improves morbidity, mortality, and quality of life—particularly peptic ulcer disease, gastric cancer prevention, MALT lymphoma, and uninvestigated dyspepsia in patients under 45-50 years without alarm symptoms. 1, 2

Primary Clinical Indications for Testing

Peptic Ulcer Disease and Complications

• Test all patients with active or past history of peptic ulcer disease, as H. pylori is responsible for approximately 90% of duodenal ulcers and 70-80% of gastric ulcers 2, 3, 4
• Patients with ulcer bleeding require testing and treatment, as eradication dramatically reduces ulcer recurrence and complications 2
• Testing is critical because untreated H. pylori infection leads to ulcer recurrence rates of 60-80% annually, while successful eradication reduces this to less than 5% 5

Gastric Cancer Prevention

• Test patients with atrophic gastritis, intestinal metaplasia, or family history of gastric cancer, as H. pylori is classified as a Class I carcinogen responsible for ~90% of gastric cancer cases 2, 3, 6
• H. pylori induces dysbiosis of gastric microbiota in the carcinogenesis pathway, and successful eradication can restore gastric homeostasis 3
• In high gastric cancer prevalence areas, testing followed by endoscopy in positive patients is appropriate 2

MALT Lymphoma

• Test all patients with gastric MALT lymphoma, as H. pylori eradication leads to complete remission in 60-80% of early-stage cases 2, 3
• Confirmation of eradication is strongly recommended in low-grade gastric MALT lymphoma 2

Uninvestigated Dyspepsia ("Test and Treat" Strategy)

• The European Society of Gastroenterology and American Gastroenterological Association recommend testing patients under 45-50 years with uninvestigated dyspepsia and no alarm symptoms (anemia, weight loss, dysphagia, palpable mass, malabsorption) 1, 2
• This "test and treat" strategy is founded on clinical and economic analyses showing cost-effectiveness by reducing unnecessary endoscopies by 62% while maintaining similar outcomes in symptom relief and quality of life 1
• The number of missed upper gastrointestinal malignancies with this approach is practically nonexistent in younger patients without alarm features 1

Other Important Indications

• Chronic NSAID or aspirin users should be tested, as H. pylori eradication reduces ulcer risk in these patients 3
• Patients requiring long-term PPI therapy (>1 year) should be tested due to increased risk of atrophic gastritis 2
• Test patients with iron deficiency anemia, idiopathic thrombocytopenic purpura, or vitamin B12 deficiency of unclear etiology 3
• Consider testing household family members of infected patients and those with family history of peptic ulcers 3

Recommended Testing Methods

For Initial Diagnosis (Non-Invasive)

• Use urea breath test (UBT) or laboratory-based monoclonal stool antigen test as first-line non-invasive tests, both achieving sensitivity and specificity of approximately 93-97% 1, 7, 2
• These tests detect active infection only, unlike serology which cannot distinguish current from past infection 7, 2
• Avoid rapid office-based serological tests, which have poor accuracy (sensitivity 63-97%, specificity 68-92%) and cannot distinguish active from past infection 7, 2

For Patients Undergoing Endoscopy (Invasive)

• Perform rapid urease test, histology, or culture during endoscopy 2
• Culture with antimicrobial susceptibility testing should be performed in regions with high clarithromycin resistance (≥15%) before first-line treatment 1, 3
• After first treatment failure, culture and susceptibility testing should be considered in all regions, as 60-70% will have resistant organisms 1

Special Testing Circumstances

• If patient recently used PPIs or antibiotics and cannot stop them, validated IgG serology may be used, as it is the only test not affected by medications that suppress bacterial load 1, 2
• Serology may also be appropriate in patients with ulcer bleeding, gastric atrophy, or gastric malignancies where bacterial density is low 1, 7, 2

Critical Testing Considerations to Avoid False Results

Medication Washout Periods

• Stop PPIs for at least 2 weeks before testing with UBT, stool antigen test, rapid urease test, histology, or culture, as PPIs cause 10-40% false-negative results 1, 2, 8
• Stop antibiotics and bismuth for at least 4 weeks before testing 2, 8
• If validated IgG serology is used, medication washout is not necessary as antibodies remain elevated despite bacterial suppression 1

Post-Treatment Confirmation

• Perform test of cure at least 4 weeks after completing eradication therapy using UBT or stool antigen test 2, 8
• Never use serology for post-treatment confirmation, as antibodies remain elevated for months to years after successful eradication 7, 2, 8
• Confirmation of eradication is strongly recommended in complicated peptic ulcer disease, gastric ulcer, and MALT lymphoma 2

Algorithm for Clinical Decision-Making

For patients under 45-50 years with dyspepsia and no alarm symptoms:

1. Perform non-invasive testing (UBT or stool antigen test) 1, 2
2. If positive, treat with appropriate eradication regimen 3, 9
3. Confirm eradication 4+ weeks after treatment completion 2, 8

For patients ≥50 years or with alarm symptoms:

1. Proceed directly to endoscopy with biopsy-based testing 2
2. Consider culture and susceptibility testing, especially in high resistance areas 1, 3

For patients on PPIs who cannot stop them:

1. Use validated IgG serology for initial diagnosis 1, 2
2. If positive, treat and confirm eradication with UBT or stool test after stopping PPIs 2, 8

Common Pitfalls to Avoid

• Do not use rapid office serological tests—they have inadequate accuracy averaging only 78% and cannot distinguish active from past infection 7, 2
• Do not test patients currently taking PPIs without either stopping them for 2 weeks or using serology instead—this leads to high false-negative rates 1, 2
• Do not use serology for post-treatment confirmation—antibodies persist long after bacterial eradication 7, 2, 8
• Do not perform testing in patients over 50 with new dyspepsia without endoscopy—they require direct visualization to exclude malignancy 2