The real-time analysis of gastric juice (Endofaster) for detection of Helicobacter Pylori: a reliable tool in substitution of histology

BACKGROUND: EndoFaster perform gastric juice analysis providing real-time Helicobacter pylori (HP) diagnosis during esophagogastroduodenoscopy (EGD), based on ammonium level. We aimed to assess its accuracy in detecting HP infection compared to the paired histology and to establish the optimum ammonium concentration cut-off point (COP). METHODS: Consecutive adult outpatients referred for EGD were prospectively enrolled between December 2021 and March 2022. In-patients, those with surgically altered anatomy, suspected neoplasia, and bleeding were excluded. EndoFaster and histology were performed in all patients, with additional stool antigen test (SAT) reserved for discordant cases. EndoFaster diagnostic measures were calculated, and ammonium level COP established using AUROC curve analysis. RESULTS:101 patients (64 female, mean age 56.7±16.1 years) were included. HP infection was diagnosed in 35 (34.6%) and 15 (14.8%) patients by EndoFaster and histology, respectively. Diagnostic accuracy in comparison with histology was 77.8% (95%CI68.3% - 85.5%). After implementing SATfor gold standard assessment, EndoFaster accuracy increased to 81.6% (95%CI 72.5%-88.7%). AUROC curve (0.93±0.03, 95%CI 0.86-0.99) identified an ammonium COP of ≥67.5ppm. Using the new COP, EndoFaster accuracy further increased to 88.8% (95%CI 80.8%-94.2%). CONCLUSIONS: Endofaster showed high accuracy for HP detection, with moderate agreement to histology. An ammonium COP of 67.5 ppm seems to be the threshold with the highest accuracy for HP detection.