Gastric quadruple test is not a substitute for gastroscopy. The Gastric Quad test mainly includes pepsinogen I and II and their ratio, as well as H. pylori antibody test, which reflects the secretion function of the stomach and whether it is infected with H. pylori. Gastric tests can be used to screen for stomach disorders, but they do not confirm the diagnosis. Gastroscopy can visualize lesions in the esophagus, stomach, and duodenum, and is commonly used to examine upper gastrointestinal diseases, including stomach, duodenum, and esophagus lesions, such as esophageal cancer, reflux esophagitis, gastritis, gastric ulcer, gastric cancer, duodenal ulcers, and gastric mesenchymal stromal tumors, etc. All of which can be diagnosed through gastroscopy. Gastric 4 is not a substitute for gastroscopy, and specific tests should be performed under the guidance of a doctor.