Indicators of blood test for gastric cancer include tumor markers, blood routine, serum pepsinogen (PG) test, Helicobacter pylori (Hp) antibody, gastrin-17 (G-17) and so on. 1. Certain tumor markers may be elevated in gastric cancer patients, such as carcinoembryonic antigen (CEA), CA72-4, glycoconjugate antigen 199 (CA199), glycoconjugate antigen 125 (CA125), etc. However, tumor markers do not have specificity, so the elevation of tumor markers can only suggest that they may suffer from malignant tumors, which can be used to assist in the diagnosis of gastric cancer and the assessment of the efficacy of treatment in the dynamic monitoring and cannot be used as the basis for confirming the diagnosis of gastric cancer. Therefore, elevated tumor markers can only indicate possible malignant tumors and be used for auxiliary diagnosis of gastric cancer and dynamic monitoring and evaluation of therapeutic effect. 2. Gastric cancer is easy to bleed, and long-term chronic bleeding can cause anemia and gastrointestinal bleeding. Patients can find signs of anemia in routine blood tests, and adult men with hemoglobin <120g/L and women with hemoglobin <110g/L are regarded as having anemia. 3. Serum PG and Hp antibody test: according to the results of serum PG concentration and Hp antibody test, the risk of gastric cancer can be stratified. 4. Serum G-17: Serum G-17 can be used to diagnose atrophic gastritis in the gastric antrum (decreased G-17 levels) or confined to the gastric body (increased G-17 levels). Chronic atrophic gastritis has a tendency to become malignant. Changes in blood test indexes can suggest the possibility of gastric cancer, but it cannot be the basis of diagnosis. The diagnosis of gastric cancer can only be confirmed through gastroscopy and biopsy of gastric mucous membrane for pathological examination. It is suggested that patients should go to the hospital as soon as possible and complete gastroscopy to make a clear diagnosis.