Gastric function four terms refers to the following group of biomarkers: pepsinogen I (PGI), pepsinogen II (PGII), pepsinogen ratio (PGR, PGI / PGII), Helicobacter pylori (Hp). Serum gastrin function is to reflect the normal gastric mucosa and gastric mucosal damage and the extent of damage, Hp treatment and prognosis of the sensitivity and specificity indicators; for atrophic gastritis, peptic ulcer, Hp infection, Early gastric cancer, high risk of gastric cancer screening to provide an effective basis. Compared with the gastroscopy, the four tests of serum gastroscope have the advantages of noninvasive painless, effective avoidance of potential iatrogenic infection, and can be widely used in healthy people, or as a gastroscope auxiliary diagnosis.