From the Guidelines
The stool antigen test and urea breath test are both effective methods for diagnosing Helicobacter pylori infection, with the most recent and highest quality study suggesting that they can be used interchangeably, with similar accuracy rates of approximately 95% 1. When choosing between the two tests, several factors should be considered, including:
- Convenience: The stool antigen test can be done at home and may be more suitable for children or patients who cannot follow breath test instructions.
- Immediate results: The breath test provides immediate results, but requires fasting and avoiding certain medications.
- Medication use: Patients should stop taking proton pump inhibitors (like omeprazole) for 2 weeks, antibiotics for 4 weeks, and bismuth preparations for 2 weeks before either test to ensure accuracy.
- Local availability and cost considerations: The choice between tests often depends on local availability and cost considerations. The most recent study, published in 2012, recommends stopping PPIs for 2 weeks before testing by culture, histology, rapid urease test, UBT or stool test, with a grade of recommendation A 1. It's also important to note that the urea breath test has a sensitivity and specificity of 94.7% and 95.7%, respectively, while the stool antigen test has a sensitivity and specificity of more than 90% in untreated patients with suspected H. pylori infection 1. In terms of patient-specific factors, the stool test may be more suitable for children or patients who cannot follow breath test instructions, while the breath test may be more suitable for patients who require immediate results. Overall, the choice between the stool antigen test and urea breath test should be based on individual patient needs and circumstances, with consideration of the most recent and highest quality evidence 1.
From the Research
Comparison of Stool Antigen Test and Breath Test for H. pylori Diagnosis
- The stool antigen test and breath test are two non-invasive methods used to diagnose H. pylori infection 2, 3.
- The breath test, also known as the urea breath test, detects the presence of H. pylori by measuring the amount of carbon dioxide produced by the bacteria in the stomach 3, 4.
- The stool antigen test, on the other hand, detects the presence of H. pylori antigens in the stool 2, 5.
- A study found that the stool antigen test is less likely to yield false-negative results compared to the breath test, especially when proton pump inhibitors (PPIs) are used 5.
- PPIs can suppress H. pylori and cause false-negative results in the breath test, but the stool antigen test is less affected by PPI use 5, 4.
- The sensitivity and specificity of the stool antigen test were found to be high, with values ranging from 75% to 100% 5.
- The breath test is also an accurate method for diagnosing H. pylori infection, but its accuracy can be affected by PPI use and other factors 3, 4.
Factors Affecting Test Accuracy
- PPI use can affect the accuracy of both the stool antigen test and the breath test, but the stool antigen test is less affected 5, 4.
- The type of test kit used can also affect the accuracy of the stool antigen test, with some kits being more sensitive and specific than others 5.
- The presence of other medical conditions, such as bleeding peptic ulcer disease, can also affect the accuracy of the breath test 3.
Clinical Implications
- The choice of test for diagnosing H. pylori infection depends on various factors, including the patient's medical history, the presence of PPI use, and the availability of test kits 2, 3.
- The stool antigen test may be a better option for patients who are taking PPIs or have other medical conditions that may affect the accuracy of the breath test 5.
- The breath test is still a widely used and accurate method for diagnosing H. pylori infection, but its limitations should be considered when interpreting test results 3, 4.