Diagnosis and Treatment of H. pylori Infection in Patients Taking PPIs

Introduction to H. pylori Diagnosis

The American Gastroenterological Association recommends that patients should not be treated for H. pylori based on a negative breath test if they were taking PPIs at the time of testing, as this represents a false-negative result in 10-40% of cases 1
PPIs increase gastric pH, which decreases H. pylori bacterial load, especially in the antrum, leading to false-negative results on urea breath tests (UBT), stool antigen tests (SAT), rapid urease tests, histology, and culture 1

Serology is the only test unaffected by PPIs because H. pylori antibodies remain present for months after bacterial suppression 1
The false-negative rate ranges from 10-40% across most diagnostic modalities during PPI use 1
Stopping PPIs for at least 2 weeks before retesting allows bacteria to repopulate the stomach, which restores test accuracy 1, 2
If stopping PPIs is not possible due to symptom management needs, validated IgG serology can be used instead, as it is not affected by acid suppression 1, 2
Only use validated commercial serological tests with >90% sensitivity and specificity 2

A positive test result during PPI use can be trusted, as PPIs cause false-negatives, not false-positives 3
H2-receptor antagonists also cause false-negatives but to a much lesser extent than PPIs, and guidelines did not find it necessary to stop them before testing if using citric acid 1
The clinical consequences of treating based on a false-negative test include missing true H. pylori infection, which increases long-term gastric cancer risk 3