What are the recommended tests for diagnosing Helicobacter pylori infection in adults?

The recommended tests for diagnosing Helicobacter pylori infection in adults are primarily the carbon-13 urea breath test and the stool antigen test, both of which demonstrate high accuracy with about 95% sensitivity and specificity. These tests are preferred in primary care settings due to their reliability in detecting active infection. It is important to avoid antibiotics and proton pump inhibitors (PPIs) before testing, as these can suppress H. pylori and lead to false-negative results. Serological testing is generally not recommended because it cannot distinguish between active and past infections, resulting in a higher false-positive rate and potential overtreatment. However, if serology is used, only locally validated tests should be employed due to variability in regional antigenic strains. For re-testing after eradication therapy, the carbon-13 urea breath test is preferred, with stool antigen testing as an alternative if breath testing is unavailable. Molecular methods and other advanced diagnostics are emerging but are not yet standard first-line tests in routine clinical practice.

This approach aligns with UK NICE guidelines and Public Health England recommendations, which emphasize the use of urea breath and stool antigen tests over serology for initial diagnosis and re-testing. Recent literature supports these recommendations, highlighting the high diagnostic accuracy of breath and stool tests and the limitations of serology. Molecular diagnostic strategies, including PCR-based methods, are being explored for their potential to detect infection and antibiotic resistance but remain adjuncts rather than replacements for established tests in primary care.

Summary:

• First-line tests: carbon-13 urea breath test and stool antigen test.
• Avoid antibiotics and PPIs before testing to prevent false negatives.
• Serological tests are not routinely recommended due to poor positive predictive value and inability to distinguish active infection.
• Re-testing after treatment: carbon-13 urea breath test preferred; stool antigen test as alternative.
• Molecular tests are promising but not yet standard for initial diagnosis.

These recommendations ensure accurate diagnosis, appropriate treatment, and help reduce unnecessary antibiotic use and resistance.

¹ (Skrebinska et al., 2018) (Ranjbar et al., 2023)