Abstract
Objective: To determine the usefulness of immunohistochemistry (IHC) in detecting Helicobacter pylori in endoscopic gastric biopsies showing chronic gastritis.
Methodology: This descriptive, prospective observational study was carried at Shifa International Hospital, Islamabad from 31st January 2020 to 1st February 2021. Non probability consecutive sampling was used. Gastric biopsies were examined for H. pylori by light microscopy. Only biopsies showing chronic inflammation were included. IHC results were also interpreted on light microscopy. Antibody highlighting brown organisms was considered positive whereas very faint, nonspecific or no staining was considered negative. Data were analyzed using SPSS version 23.0 and post stratification Chi square test was applied.
Results: Out of 307 cases, 186 (60.59%) had H. pylori associated gastritis. Out of these, 91(29.6%) showed activity and 95 (30.9%) did not show any activity. In 126 (41.03%) cases, H. pylori were identified on H&E. Out of these, 109 (35.5%) were confirmed on IHC and in 77 (25.08%), H. pylori were identified on IHC which were not visible on H&E.
Conclusion: IHC increases the yield of H. pylori detection in gastric biopsies submitted for histopathological examination. It must be performed in all cases with inflammation where H. pylori are not visualized on routine H&E stain.

Key words: Helicobacter pylori, chronic gastritis, immunohistochemistry.