Can I test my patient for H. pylori (Helicobacter pylori) infection using an H. pylori antigen test while they are on Proton Pump Inhibitor (PPI) therapy?

From the Guidelines

It's not recommended to test for H. pylori using an antigen test while your patient is on a proton pump inhibitor (PPI). PPIs like omeprazole, pantoprazole, or esomeprazole can suppress H. pylori and lead to false-negative test results, as stated in the study by 1. For accurate H. pylori testing, PPIs should be discontinued at least 2 weeks before performing the stool antigen test, as recommended by 1. During this waiting period, the patient can use antacids if needed for symptom relief, as these don't interfere with test results.

The reason for this recommendation is that PPIs reduce stomach acid production, which creates an environment where H. pylori may become less active and shed fewer antigens into the stool, making detection more difficult. If testing while on PPIs is absolutely necessary, be aware that a positive result may be reliable, but a negative result should be interpreted with caution as it could be falsely negative. For optimal diagnostic accuracy, schedule the test after the appropriate PPI washout period.

Some key points to consider when testing for H. pylori include:

• PPIs can decrease the bacterial load in the stomach, leading to false-negative test results 1
• Stopping PPIs for at least 2 weeks before testing allows the bacteria to repopulate the stomach and increases the accuracy of the test 1
• Antacids can be used during the waiting period for symptom relief without interfering with test results
• A positive test result while on PPIs may be reliable, but a negative result should be interpreted with caution 1

In terms of the evidence, the most recent and highest quality study, 1, supports the recommendation to discontinue PPIs for at least 2 weeks before testing for H. pylori. Additionally, the study by 1 provides further guidance on the management of H. pylori infection and the use of diagnostic tests. The study by 1 provides information on the accuracy of urea breath testing, but is less relevant to the specific question of testing for H. pylori using an antigen test while on PPIs.

From the Research

H. pylori Antigen Test and PPI Therapy

• The H. pylori antigen test can be used to detect H. pylori infection, but its accuracy may be affected by Proton Pump Inhibitor (PPI) therapy 2.
• Studies have shown that PPI therapy can cause false-negative results in H. pylori diagnostic tests, including the urea breath test and biopsy culture 3, 4.
• However, the stool antigen test (SAT) may be less likely to yield false-negative results, even when PPIs are used 2.
• One study found that the sensitivity and specificity of SAT using a bioluminescent enzyme immunoassay were not significantly affected by PPI administration 2.

Effects of PPIs on H. pylori Diagnostic Tests

• PPIs can inhibit the growth of H. pylori and reduce its urease activity, leading to false-negative results in diagnostic tests 4.
• The negative effects of PPIs on H. pylori diagnostic tests can be transient, and cessation of PPI consumption for at least 12 days before endoscopy may help avoid false-negative results 4.
• However, the stool antigen test may be a reliable option for detecting H. pylori infection, even in patients taking PPIs 2.

Recommendations for H. pylori Testing

• Patients should not receive PPIs for 2 weeks before receiving the urea breath test for H. pylori infection 3.
• Cessation of PPI consumption for at least 12 days before endoscopy may help avoid false-negative results in H. pylori diagnostic tests 4.
• The stool antigen test using a bioluminescent enzyme immunoassay may be a reliable option for detecting H. pylori infection, even in patients taking PPIs 2.