S1283 Reassessing Gastric Biopsies in Normal-Appearing Mucosa: A Retrospective Study Evaluating the Impact of Discontinuing Immunohistochemical Staining

Introduction: Helicobacter pylori can be diagnosed using both invasive and non-invasive methods. Among invasive techniques, histological analysis of gastric biopsies is the gold standard. These are typically examined with Hematoxylin and Eosin (H&E) staining, and Immunohistochemical (IHC) staining is often added to enhance diagnostic accuracy. However, this approach is resource-intensive, costly, and has prolonged turnaround times. As clinical practice shifts toward reducing invasive testing, especially in the setting of endoscopically normal gastric mucosa, the utility of routine biopsies and IHC staining in such cases warrants reevaluation. This study aimed to assess biopsy rates and diagnostic yield in patients with normal-appearing gastric mucosa before and after our institution discontinued IHC staining in these biopsies. Methods: We conducted a retrospective cohort study across a multicenter health system. After institutional review board approval, we reviewed all EGDs performed in 2 time periods: Sep 1–Oct 31, 2023 (control group, when IHC was performed) and Jan 1–Feb 28, 2024 (case group, after IHC was discontinued). Patients with findings of normal gastric mucosa on EGD were included. The primary outcome was biopsy rate; the secondary outcome was histologic yield for H. pylori. Results: A total of 217 patients met inclusion criteria, 102 (47%) in the control group and 115 (53%) in the case group. There were no significant differences in age, gender, race, or proton pump inhibitor use. Common EGD indications included anemia, dyspepsia, abdominal pain, heartburn, melena, and reflux, with similar distribution between groups. Gastric biopsies were taken in 72/102 (70.6%) patients in the control group vs 74/115 (64.3%) in the case group (P = 0.33). IHC staining was performed in 72 (70.6%) control patients compared to 25 (21.7%) in the case group (P < 0.01). Histology was positive for H. pylori in 15 (14.7%) control patients vs 13 (11.3%) case patients (P = 0.67). Conclusion: Reducing the use of IHC staining in biopsies from normal-appearing gastric mucosa did not affect the rate of biopsy nor the diagnostic yield for H. pylori. Despite a significant decrease in IHC utilization, detection rates remained unchanged. These findings suggest that routine biopsy and IHC staining of endoscopically normal gastric mucosa may have limited clinical value. Larger studies are warranted to evaluate the cost-effectiveness of invasive histologic evaluation compared to non-invasive diagnostic methods.