# Validation of a Gastric-Juice-Analysis-Based Approach to H. pylori Diagnosis

## TL;DR

This study validates a new method for diagnosing H. pylori infection using gastric juice analysis during endoscopy, reducing the need for biopsies.

## Contribution

The study introduces a reliable non-biopsy diagnostic approach for H. pylori using ammonium concentration thresholds in gastric juice.

## Key findings

- An ammonium cut-off of 62 ppm/mL ruled out H. pylori with 90% sensitivity in the training cohort.
- Endofaster® showed 70% sensitivity and 93% specificity in the validation cohort for H. pylori detection.
- Indeterminate results occurred in 15% of validation cases, requiring gastric biopsies for confirmation.

## Abstract

Background: Although the incidence of H. pylori infection is decreasing globally, it is not completely negligible. Because H. pylori infection is associated with various pathologies, ranging from peptic ulcer disease to neoplastic lesions, research into and treatment of H. pylori infections remain important. Objectives: We aimed to assess the diagnostic performance of gastric juice analysis (Endofaster®) for the detection of H. pylori in patients undergoing esophagogastroduodenoscopy (EGDS), using conventional histology as the reference standard. Our secondary objectives were to identify the optimal ammonium concentration thresholds for defining positive and negative results and to propose a clinical flowchart to support patient management. Methods: The diagnostic accuracy of Endofaster was first analyzed using an unmatched training cohort comprising an equal number of H. pylori-positive patients (n = 30) and negative controls (n = 30) who underwent EGDS. The derived thresholds were subsequently evaluated in an independent validation cohort of patients who underwent EGDS with Endofaster. Histological examination is the gold standard for H. pylori diagnosis. Results: In the training cohort, an ammonium concentration cut-off of 62 ppm/mL yielded a sensitivity of 90% (95% CI: 74–97%) for ruling out H. pylori infection. For confirming infection, the optimal cut-off was 100 ppm/mL, corresponding to a specificity of 95% (95% CI: 83–99%). Ammonium values > 62 and <100 ppm/mL were considered indeterminate, suggesting gastric biopsy was required for confirmation. The validation cohort included 196 patients (mean age: 59.9 ± 12.7 years), with a histology-based H. pylori prevalence of 19%. In this cohort, Endofaster® demonstrated a sensitivity of 70% (95% CI: 51–85%) and a specificity of 93% (95% CI: 88–97%). Indeterminate results were observed for 29 patients (15%). Conclusions: Endofaster® provides a largely reliable diagnosis of H. pylori infection during EGDS when a decision-making approach is applied, allowing gastric biopsies to be reserved for indeterminate cases only.