Commonly used screening methods for Helicobacter pylori include non-invasive methods such as carbon 13 or carbon 14 breath test, Helicobacter pylori antibody test, and invasive methods such as rapid urease test and pathologic testing of a small amount of gastric mucosal tissue taken under gastroscopy. 1. Non-invasive methods (1) Breath test: it can be divided into carbon 13 breath test and carbon 14 breath test, which are simple, painless and inexpensive, and their sensitivity and specificity are similar to that of gastroscopy. (2) Helicobacter pylori antibody test: easy to perform and inexpensive, positive blood antibody suggests previous infection with Helicobacter pylori, but it is not possible to determine whether it is a symptomatic infection. 2. Invasive examination: invasive examination is to use biopsy forceps to take a piece of gastric mucosa tissue for further testing during gastroscopy. (1) Rapid urease test: the gastric mucosal tissue removed by gastroscopy is soaked in reagent for testing, and if the reagent changes color, it suggests the presence of H. pylori infection. (2) Histological examination: the tissue taken out from gastroscopy is sent to the Department of Pathology for special staining examination to detect H. pylori infection, but it takes longer time and the operation procedure is more cumbersome.