Objective: To determine sensitivity, specificity, accuracy to diagnose H. pylori in dyspepsia patients by re-used Pronto Dry test Design: Diagnostic cross-sectional study. Setting : Rajavithi Hospital.Method: 202 patients with symptom of dyspepsia that need endoscopic procedure to make diagnosis were enrolled in this study. After complete examination duodenum, stomach, 3 pieces of gastric mucosa each from antrum and body were obtained and randomly allocated for histology with immunohistochemistry, new Pronto Dry, re-used Proto Dry. Results of all these tests, age, sex were recorded. Results: This study showed that sensitivity, specificity, accuracy of re-used Pronto Dry test were 61.70% (95% C147.29-74.70), 96.77% (95% CI 92 .99-.98.81), 88.61% (95% CI 83.66-92.46) respectively, and the kappa agreement between re-used Pronto Dry test and new Pronto Dry test was 0.63(95%CI 0.51-0.74). Prevalence of functional dyspepsia was 7.9% and prevalence of H. pylori infection was 23%. There was no adverse event in this study. Conclusion: Re-used Pronto Dry test could be used to diagnose H. pylori infection with intermediate sensitivity, and high specificity, therefore It is not recommended to use for screening test of H. pylori infection.