Anemia is a clinical syndrome that occurs when the volume of red blood cells in the peripheral blood is lower than normal. Anemia is a symptom that can be caused by a variety of diseases. Routine blood tests can detect anemia and make general inferences about the type of anemia. Routine blood tests can reveal the following problems: i. The number of red blood cells. The lower the number of red blood cells, the more severe the anemia is. Second, the red blood cell pressure. In the case of anemia, the red blood cell pressure volume is reduced. Third, hemoglobin concentration. The more severe the anemia is, the lower the hemoglobin concentration will be. And according to the degree of decrease of hemoglobin concentration, anemia is divided into four degrees, there are mild anemia, moderate anemia, severe anemia and very severe anemia. In addition, the average red blood cell volume, average red blood cell hemoglobin volume and average red blood cell hemoglobin concentration are three indicators that can make a general inference about the type of anemia.