The value of hemoglobin in the routine blood test is to look at anemia. According to the World Health Organization, anemia is diagnosed based on the amount of hemoglobin in the body, and the indicator of hemoglobin varies by age and gender. Anemia is diagnosed in adult men with hemoglobin <130g/L, in adult women with hemoglobin <120g/L, and in pregnant women with hemoglobin <110g/L. Hemoglobin is the main component of red blood cells and is composed of iron ions and pearl protein. The human body is rich in protein reserves, but the iron content is limited, so most of the problems of anemia appear in iron ions, which is one of the trace element tests, and transferrin saturation, ferritin, etc. can check whether it is iron deficiency anemia.