Is there a test for Helicobacter pylori (H. pylori) that can be done while the patient is taking Proton Pump Inhibitors (PPI)?

From the Guidelines

Yes, there is a test for H. pylori that can be done while the patient is taking PPI, and that is the validated IgG serology test. The use of proton pump inhibitors (PPIs) can affect the accuracy of certain tests for H. pylori, such as the urea breath test (UBT), stool antigen test, and biopsy-based tests, potentially leading to false-negative results 1. This is because PPIs increase the gastric pH, leading to a decrease in the bacterial load, especially in the antrum. However, serological tests that detect antibodies against H. pylori remain accurate even during PPI therapy because they detect past exposure rather than active infection.

Key Points to Consider

• The stool antigen test and the urea breath test can be affected by PPI use, potentially leading to false-negative results 1.
• Serological tests (blood tests) that detect antibodies against H. pylori remain accurate even during PPI therapy because they detect past exposure rather than active infection 1.
• For optimal accuracy with other testing methods, it's generally recommended to discontinue PPIs for 2 weeks before testing, allowing the stomach environment to return to its natural acidic state, which is necessary for H. pylori to flourish and be detectable 1.
• PPIs reduce stomach acid production, which can suppress H. pylori activity without eradicating the infection, making the bacteria harder to detect while the medication is active in the body.

Testing Recommendations

• If possible, PPIs should be stopped for 2 weeks before testing by culture, histology, rapid urease test, UBT, or stool test 1.
• If it is not possible to stop PPIs, validated IgG serology can be performed as an alternative 1.

From the Research

H. pylori Testing while Taking PPI

• There are tests for H. pylori that can be done while the patient is taking Proton Pump Inhibitors (PPI), such as the stool antigen test (SAT) 2.
• The SAT, particularly when using domestically produced kits, may be less likely to yield false-negative results compared to the 13C-urea breath test (UBT) 2.
• A study found that the sensitivities and specificities of SAT kits, such as Quick Navi™-H. pylori, Quick Chaser® H. pylori, and BLEIA® 'EIKEN' H. pylori Antigen, were not significantly affected by PPI administration 2.
• However, other studies suggest that PPI therapy can lead to false-negative H. pylori test results, and treatment should be stopped for 1-2 weeks prior to testing if possible 3, 4.
• The reliability of stool antigen tests can vary, with some studies showing lower sensitivity and specificity compared to other diagnostic methods 5.
• Antacids do not appear to impair the sensitivity of breath tests or stool tests, whereas PPIs can decrease the sensitivity of these tests 6.

Test Options

• Stool antigen test (SAT) using domestically produced kits, such as Quick Navi™-H. pylori, Quick Chaser® H. pylori, and BLEIA® 'EIKEN' H. pylori Antigen 2.
• Urea breath test (UBT), although its sensitivity may be decreased by PPI administration 3, 6.
• Biopsy urease test and histology, which are invasive tests that can accurately identify current infection 3.
• Immunoblot and molecular methods, which may be useful for detecting H. pylori infection in difficult cases 4.