Helicobacter pylori (H pylori) is a spiral-shaped bacterial infection of the stomach lining; one of the most common chronic infections worldwide. Prevalence – about 30-40% of U.S. adults; 50-70% in developing countries; often acquired in childhood. Most infections asymptomatic but can cause peptic ulcers (gastric, duodenal); chronic gastritis; gastric cancer (H pylori is Class I carcinogen); MALT lymphoma; possibly iron-deficiency anemia; possibly idiopathic thrombocytopenic purpura (ITP); functional dyspepsia in some. Indications for testing – active peptic ulcer disease; history of peptic ulcers; dyspepsia in adults under 60 without alarm features; long-term NSAID or aspirin therapy; family history of gastric cancer; gastric MALT lymphoma; unexplained iron-deficiency anemia; ITP. Test before treating long-term NSAID users; consider in immigrants from high-prevalence countries with dyspepsia. After treatment – “test of cure” 4 weeks after antibiotic completion to confirm eradication. Multiple test methods – urea breath test (patient swallows urea labeled with carbon isotope; H pylori urease enzyme converts to labeled CO2; very accurate 95% sensitivity/specificity; good for diagnosis and test of cure); stool antigen test (detects H pylori antigens; very accurate; convenient); blood antibody test (serology – detects IgG antibodies; widely available; cheap; BUT can’t distinguish active vs past infection; not for test of cure); endoscopy with biopsy (most invasive; for symptoms warranting endoscopy). Preparation requirements – urea breath test and stool antigen need to be off PPIs 2 weeks, off antibiotics 4 weeks, off bismuth 4 weeks (false negatives). Serology not affected. Best initial test typically – urea breath test or stool antigen for non-invasive cases. Emerging research area with mixed evidence. Some studies suggest higher H pylori prevalence in adults with type 2 diabetes (about 1.5x more common); H pylori infection associated with worse glycemic control; eradication may modestly improve A1C; possible link to insulin resistance. Mechanisms proposed – chronic inflammation affecting insulin sensitivity; gut microbiome changes; effect on incretin hormones (GLP-1, GIP); altered absorption of nutrients. However – evidence inconsistent; routine screening NOT currently recommended just because of diabetes. American Diabetes Association does not recommend routine H pylori screening for asymptomatic diabetes patients.
H Pylori Test Options
| Test | Sample | Accuracy | Use |
|---|---|---|---|
| Urea breath test | Breath | ~95% | Diagnosis and test of cure |
| Stool antigen test | Stool | ~95% | Diagnosis and test of cure |
| Blood antibody (serology) | Blood | ~85% | Initial screen only; can’t distinguish active/past |
| Endoscopy + biopsy | Tissue | ~95% | If endoscopy needed for symptoms |
| Rapid urease test (CLO) | Tissue (at endoscopy) | ~90% | During endoscopy |
Indications for Testing
- Active peptic ulcer disease (PUD).
- History of peptic ulcers.
- Dyspepsia in adults under 60 (without alarm features).
- Long-term NSAID or aspirin therapy.
- Family history of gastric cancer.
- Gastric MALT lymphoma.
- Unexplained iron-deficiency anemia.
- Idiopathic thrombocytopenic purpura (ITP).
- Immigrants from high-prevalence countries with dyspepsia.
- Before long-term NSAID therapy.
- Functional dyspepsia after failure of other treatments.
- Test of cure after treatment.
Treatment Regimens
- Bismuth quadruple therapy (preferred first-line in many regions) – PPI + bismuth subsalicylate + tetracycline + metronidazole for 10-14 days.
- Clarithromycin triple therapy (where resistance is low) – PPI + clarithromycin + amoxicillin for 14 days.
- Concomitant therapy – PPI + amoxicillin + clarithromycin + metronidazole for 10-14 days.
- Sequential therapy – 5 days of PPI + amoxicillin, then 5 days PPI + clarithromycin + metronidazole.
- Levofloxacin triple therapy – for retreatment.
- Common side effects – taste changes (metallic), diarrhea, nausea, black stools (bismuth – normal).
- Complete entire course to prevent resistance.
- Test of cure 4 weeks after antibiotic completion.
Diabetes Considerations
- Some studies suggest 1.5x higher H pylori in diabetes.
- Mechanisms – chronic inflammation, gut microbiome changes.
- May modestly worsen glycemic control if untreated.
- Eradication may modestly improve A1C.
- NOT recommended for routine screening in asymptomatic diabetes.
- DO test if symptoms or risk factors present.
- Long-term PPI use in diabetes – watch for B12 deficiency.
- Antibiotic treatment – monitor blood sugar (illness stress).
- CGM helpful during treatment.
- Consider metformin GI side effects vs H pylori symptoms.
Alarm Features (Warrant Endoscopy First)
- Age 60 or older with new dyspepsia.
- Unintentional weight loss.
- Persistent vomiting.
- Dysphagia (difficulty swallowing).
- GI bleeding (vomiting blood, black stools).
- Iron deficiency anemia (unexplained).
- Abdominal mass.
- Family history of gastric cancer.
Test Preparation
- Urea breath test – off PPIs 2 weeks (esomeprazole, omeprazole, others).
- Off H2 blockers (ranitidine, famotidine) 1-2 days.
- Off antibiotics 4 weeks before testing.
- Off bismuth subsalicylate (Pepto-Bismol) 4 weeks.
- Fast 1 hour before breath test.
- Stool antigen has similar preparation requirements.
- Serology – no preparation needed.
- Endoscopy – fast 8 hours; sedation; arrange ride.
The Bottom Line
Helicobacter pylori (H pylori) is a spiral-shaped bacterial infection of the stomach lining; one of the most common chronic infections worldwide. Prevalence – about 30-40% of U.S. adults; 50-70% in developing countries; often acquired in childhood. Most infections asymptomatic but can cause peptic ulcers (gastric, duodenal); chronic gastritis; gastric cancer (H pylori is Class I carcinogen); MALT lymphoma; possibly iron-deficiency anemia; possibly idiopathic thrombocytopenic purpura (ITP); functional dyspepsia in some. Indications for testing – active peptic ulcer disease; history of peptic ulcers; dyspepsia in adults under 60 without alarm features; long-term NSAID or aspirin therapy; family history of gastric cancer; gastric MALT lymphoma; unexplained iron-deficiency anemia; ITP; immigrants from high-prevalence countries with dyspepsia. After treatment – “test of cure” 4 weeks after antibiotic completion. Multiple test methods – urea breath test (very accurate 95%; good for diagnosis and test of cure); stool antigen test (very accurate; convenient; good for diagnosis and test of cure); blood antibody test (can’t distinguish active vs past; not for test of cure; less useful); endoscopy with biopsy (most invasive; for symptoms warranting endoscopy). Preparation – urea breath test and stool antigen need to be off PPIs 2 weeks, off antibiotics 4 weeks, off bismuth 4 weeks. Emerging area of research with mixed evidence about diabetes connection. Some studies suggest higher H pylori prevalence in adults with type 2 diabetes (about 1.5x more common); H pylori infection associated with worse glycemic control; eradication may modestly improve A1C; possible link to insulin resistance. Mechanisms proposed – chronic inflammation affecting insulin sensitivity; gut microbiome changes; effect on incretin hormones; altered absorption of nutrients. However – evidence inconsistent; routine screening NOT currently recommended just because of diabetes. American Diabetes Association does not recommend routine H pylori screening for asymptomatic diabetes patients. Reasonable scenarios for testing in diabetes – dyspepsia symptoms; long-term metformin causing GI symptoms (rule out other causes); on PPI long-term; family history of gastric cancer; failed dyspepsia treatment. Antibiotic treatment regimens – bismuth quadruple therapy (preferred first-line in many regions); clarithromycin triple therapy (where resistance is low); concomitant therapy; sequential therapy. Common side effects – taste changes, diarrhea, nausea, black stools (bismuth). Complete entire course to prevent resistance. Test of cure 4 weeks after antibiotic completion using urea breath test or stool antigen (NOT serology). Eradication rate 70-90% first attempt. For adults with diabetes – test if dyspepsia, ulcer history, or other indication; monitor blood sugar during antibiotic treatment; eradication may modestly improve glucose control; routine screening for asymptomatic diabetes not recommended. See our broader prediabetes detection guide.
