What is better for detecting H. pylori, breath test or stool test?

Urea Breath Test vs. Stool Test for H. pylori Detection

The urea breath test (UBT) is slightly better than the stool antigen test for detecting H. pylori infection, with higher sensitivity (94.7-97% vs 93%) and specificity (95-95.7% vs 93%), though both are excellent non-invasive diagnostic options. 1, 2

Comparison of Non-invasive H. pylori Tests

Urea Breath Test (UBT)

• Considered the gold standard among non-invasive tests with excellent sensitivity (94.7-97%) and specificity (95-95.7%) 1
• Directly detects active infection rather than past exposure 1
• Available in two forms: 13C (non-radioactive) and 14C (radioactive) 1
• 13C version is safer for use in children and pregnant women 1
• Requires patient to fast for at least 6 hours before testing 1

Stool Antigen Test

• Highly accurate with sensitivity and specificity of approximately 93% 1, 3
• Directly detects H. pylori bacterial antigens in stool specimens, confirming active infection 3
• Does not require specialized equipment like the mass spectrometer needed for 13C-UBT 1
• More practical in some settings as it doesn't require patient presence for testing 3
• Some patients may have aversion to collecting stool samples 3

Factors Affecting Test Accuracy

• Recent use of antibiotics can cause false-negative results in both tests 1
• Proton pump inhibitors (PPIs) should be withheld for at least 7 days before testing 1, 2
• Bismuth compounds should be withheld for at least 4 weeks before testing 1, 2
• Patients should fast for at least 6 hours before UBT 1

Clinical Recommendations

When to Choose UBT

• When highest accuracy is required 1
• For patients who don't mind coming to the clinic for the test 1
• When immediate results are needed (some UBT protocols provide faster results) 1
• For children and pregnant women (using 13C-UBT) 1

When to Choose Stool Antigen Test

• When patient compliance with fasting requirements is a concern 3
• When testing needs to be done remotely (sample can be mailed) 1, 3
• When specialized equipment for UBT is not available 1
• For post-treatment confirmation of eradication 1, 3

Tests to Avoid

• Serology tests should not be used as primary diagnostic method as they cannot distinguish between active infection and past exposure 1, 2
• Office-based serologic tests are less accurate than laboratory-based tests 1
• Serology tests should not be used to confirm eradication after treatment 1, 2

Important Clinical Considerations

• Both UBT and stool antigen tests are recommended by the European Helicobacter Pylori Study Group for initial diagnosis of H. pylori infection 1
• Both tests are valuable in the "test and treat" strategy for young dyspeptic patients without alarm symptoms 3, 2
• For confirmation of eradication, testing should be performed at least 4 weeks after completion of treatment 2
• In patients with bleeding ulcers, false-negative results may occur with both tests, and serology may be more reliable in this specific situation 2

Pitfalls to Avoid

• Failure to stop PPIs before testing can lead to false-negative results in both UBT and stool antigen tests 1, 2
• Using rapid in-office serological tests which have limited accuracy 2
• Relying on serology to confirm eradication after treatment 1, 2
• Testing too soon after completion of treatment (should wait at least 4 weeks) 2