Comparison of Non-invasive Diagnostic Methods for Helicobacter Pylori Infection Before and After Treatment.

INTRODUCTION

Helicobacter pylori (H. pylori) infection is a major contributor to peptic ulcer disease and other gastrointestinal disorders. The present study aimed to investigate the effect of treatment on diagnostic outcomes by comparing two non-invasive methods-the stool antigen test and the serological IgG antibody test, before and after therapy. This approach was designed to evaluate not only the diagnostic efficacy of these tools but also the changes in antibody responses following eradication treatment.

METHODS

This observational study was conducted from 2021 to 2022 at Shahid Motahari Clinic, affiliated with Shiraz University of Medical Sciences, Shiraz, Iran. A total of 108 patients with dyspepsia and confirmed H. pylori infection were enrolled. Diagnostic tests included stool antigen, anti-H. pylori IgG serology, and the urease breath test (UBT). Patients received standard triple therapy, with stool antigen and IgG levels measured before and one month after treatment to assess diagnostic accuracy and treatment outcomes.

RESULTS

Among 108 patients, 74% had peptic ulcer disease. The UBT showed the highest diagnostic accuracy (100% sensitivity, 94.6% specificity). Anti-H. pylori IgG serology had high sensitivity (100%) but lower specificity (66.2%). The stool antigen test demonstrated moderate accuracy. After treatment, stool antigen levels significantly decreased (from 4.2±0.64 to 2.9±0.75, P=0.03), and IgG titers declined significantly (from 54.26±3.33 to 46.51±3.22, P<0.0001).

CONCLUSION

Our findings underscore UBT as the most accurate method and highlight the value of stool antigen testing for follow-up. Monitoring IgG titer changes may support treatment assessment when used alongside other tools, though its low specificity limits stand-alone use.