This test is used to aid in the diagnosis of H. pylori infection in children with symptoms of gastric disease. H. pylori is one of the main causes of gastric and duodenal ulcer disease, and several antibiotics have been shown to inhibit or kill H. pylori and help heal ulcers. The clinical diagnosis of the disease can be confirmed by combining this test, gastroscopy findings and its clinical symptoms to facilitate early treatment. Children with recurrent pain in the upper abdomen, nausea, vomiting, vomiting blood, belching, acid reflux, long-term chronic diarrhea, abdominal pain, and parents who are in close contact with children with these symptoms need to be screened for this item.