How to Order H. pylori Testing in the Lab
For an adult patient with dyspepsia and ulcer history not scheduled for endoscopy, order either a ¹³C-urea breath test or a laboratory-based monoclonal stool antigen test after stopping proton pump inhibitors for at least 2 weeks and antibiotics/bismuth for at least 4 weeks. 1, 2
Pre-Test Medication Management (Critical Step)
Before ordering any H. pylori test, you must ensure proper medication washout to avoid false-negative results:
Stop proton pump inhibitors (PPIs) for at least 2 weeks before testing 1, 2, 3
Stop antibiotics and bismuth compounds for at least 4 weeks before testing 1, 2
Serology is the only test unaffected by PPI therapy and can be used if medication washout is not possible, though it has significant limitations 2, 3
Recommended Non-Invasive Tests (First-Line)
Two tests are recommended with equivalent accuracy:
Urea Breath Test (¹³C-UBT)
- Sensitivity: 94-97%, Specificity: 95-97.7% 2, 3
- Patient must fast for at least 6 hours before the test 3
- Most accurate non-invasive test available 4
- Order as: "¹³C-urea breath test for H. pylori"
Stool Antigen Test
- Sensitivity: 93.2%, Specificity: 93.2% 1, 2
- Must specify laboratory-based monoclonal antibody test 1, 2
- Avoid rapid in-office immunochromatographic versions (accuracy only 80-81%) 3
- Order as: "H. pylori stool antigen test (laboratory-based monoclonal)"
Tests to Avoid for Initial Diagnosis
Do not order serology for routine diagnosis:
- Cannot distinguish active infection from past exposure 4, 2, 3
- Antibodies persist for months to years after eradication 3
- Overall accuracy only 78% (range 68-82%) 2, 3
- Rapid in-office serological tests have even lower accuracy (63-97% sensitivity, 68-92% specificity) 2
Limited exceptions where serology may be considered:
- Patient cannot stop PPIs/antibiotics and testing cannot be delayed 2, 3
- Gastric atrophy, malignancy, or ulcer bleeding where bacterial load is low 2
Clinical Context: When to Order Non-Invasive Testing
Appropriate for non-invasive testing (no endoscopy needed):
- Age < 50-55 years without alarm symptoms 4, 2
- Dyspepsia symptoms present for ≥4 weeks 4
- History of ulcer disease (as in your patient) 2
Proceed directly to endoscopy instead (do not order non-invasive tests):
- Age ≥ 50-55 years with new-onset dyspepsia 4, 2
- Any alarm symptoms present regardless of age 4, 2:
- Unintentional weight loss
- Progressive dysphagia
- Gastrointestinal bleeding or anemia
- Palpable abdominal mass
- Recurrent vomiting
- Family history of gastric cancer 2
Timing for Post-Treatment Testing
If ordering testing to confirm eradication after treatment:
- Wait at least 4 weeks after completing eradication therapy 1, 2, 3
- Use urea breath test or stool antigen test only 1, 2
- Never use serology to confirm eradication 2, 3
Common Pitfalls to Avoid
- Do not order H. pylori testing while patient is on PPIs unless serology is specifically chosen 2
- Do not order rapid in-office stool tests – specify laboratory-based monoclonal test 1, 3
- Do not order serology panels (IgG, IgA, IgM) – provides no added benefit over validated IgG alone 2
- Do not order testing in patients with typical irritable bowel syndrome rather than dyspepsia 4
- Do not skip medication washout periods – this is the most common cause of false-negative results 1, 2
Practical Ordering Instructions
For your specific patient (adult with dyspepsia and ulcer history, no endoscopy planned):
- Verify patient has stopped PPIs for ≥2 weeks and antibiotics/bismuth for ≥4 weeks
- Order either:
- "¹³C-urea breath test for H. pylori detection" (patient fasts 6 hours before) OR
- "H. pylori stool antigen test, laboratory-based monoclonal antibody method"
- If positive, initiate eradication therapy immediately 2
- Retest at least 4 weeks after completing treatment using the same non-invasive method 1, 2