What is the best approach to diagnose and treat stomach ulcers in adults, including those with a history of dyspepsia, abdominal pain, or bleeding, and considering factors such as age and alarm symptoms like weight loss, dysphagia, or anemia?

Testing for Stomach Ulcers

For patients under 50 years without alarm symptoms (bleeding, weight loss, dysphagia, anemia), use non-invasive H. pylori testing with either a 13C-urea breath test or laboratory-based monoclonal stool antigen test—both have approximately 93-98% accuracy—and treat if positive without requiring endoscopy. 1, 2

Age-Based Diagnostic Algorithm

Younger Patients (<50 years) Without Alarm Features

• First-line approach: Perform non-invasive H. pylori testing using either 13C-urea breath test (sensitivity 94.7-97%, specificity 95-95.7%) or laboratory-based monoclonal stool antigen test (sensitivity 93.2%, specificity 93.2%) 1, 3

• Critical medication washout: Stop proton pump inhibitors for at least 2 weeks before testing, and discontinue antibiotics or bismuth for at least 4 weeks, as these cause 10-40% false-negative rates 1, 4

• Avoid serology: Commercial ELISA serology tests average only 78% accuracy and cannot distinguish active infection from past exposure, making them inadequate for clinical use 1

• Immediate treatment: If H. pylori positive, initiate eradication therapy without endoscopy—this strategy reduces unnecessary endoscopies by 62% while maintaining equivalent safety 5, 2

Older Patients (≥50 years) or Any Age With Alarm Symptoms

• Proceed directly to endoscopy with invasive testing (rapid urease test, histology, or culture) for patients over 50 with new-onset dyspepsia or any patient presenting with alarm features 1, 2

• Alarm symptoms requiring immediate endoscopy: Gastrointestinal bleeding, unintentional weight loss, dysphagia (difficulty swallowing), palpable abdominal mass, anemia, or malabsorption 5, 1, 2

• Rationale: Older age and alarm features significantly increase the likelihood of finding serious organic pathology including malignancy, peptic ulcer disease, or complicated gastric conditions 6, 7

Specific Testing Methods

Non-Invasive Tests (Primary Care Setting)

13C-Urea Breath Test:

• Most accurate non-invasive option with 98.1% sensitivity and 95.1% specificity 3
• Detects active infection only, making it valuable for both initial diagnosis and post-treatment confirmation 1
• Safe for all populations including children and pregnant women (avoid radioactive 14C version) 1

Laboratory-Based Monoclonal Stool Antigen Test:

• Comparable accuracy to breath test with 93.2% sensitivity and specificity 1
• Detects active infection through bacterial antigens in stool specimens 1
• Critical pitfall: Rapid in-office immunochromatographic stool tests have significantly lower accuracy and should be avoided—only laboratory-based monoclonal antibody tests achieve high accuracy 1

Serology (Limited Use Only):

• Use only when recent antibiotic or PPI use prevents other testing, or in cases of ulcer bleeding, gastric atrophy, or malignancy where bacterial load may be low 1
• Cannot confirm eradication after treatment as antibodies persist long after bacterial elimination 1
• Positive predictive value falls dramatically in low-prevalence populations 1

Invasive Tests (During Endoscopy)

• Rapid urease test: Provides quick results during the procedure 1
• Histology: Requires at least two biopsy samples from antrum and body for improved sensitivity, allows visualization of bacteria and assessment of mucosal damage 1
• 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%) 1, 4

Post-Treatment Confirmation

• Timing: Test for eradication at least 4 weeks after completing treatment 1, 2

• Preferred methods: Use urea breath test or laboratory-based monoclonal stool antigen test (sensitivity 91.6%, specificity 98.4%) for post-treatment confirmation 1

• Never use serology for confirmation as antibodies remain elevated after H. pylori elimination 1

• Mandatory confirmation in: Complicated peptic ulcer disease, gastric ulcer, and low-grade gastric MALT lymphoma 1, 2

Common Pitfalls to Avoid

• PPI interference: Proton pump inhibitors cause false-negative results in all tests except serology—this is the most common testing error in clinical practice 1, 4

• Inadequate washout periods: Histamine-2 receptor antagonists can be substituted for PPIs when acid suppression is needed before testing, as they do not affect bacterial load 1

• Using whole blood rapid tests: These have inadequate sensitivity and specificity (<90%) and should not be used 5, 1

• Testing panels of IgG, IgA, and IgM: These provide no added benefit over validated IgG tests alone and may include non-FDA-approved tests of unclear diagnostic value 1

Cost-Effectiveness Considerations

• The test-and-treat strategy costs £205.67 per patient per year compared to £404.31 for immediate endoscopy 5

• This approach is as effective and safe as endoscopy in younger patients without alarm features, while being equally reassuring to patients 5, 8

• Despite higher individual test costs for breath and stool tests compared to serology, their improved accuracy makes them cost-effective by avoiding unnecessary treatments and complications 5