Primitive cells are newborn, undeveloped blood cells in the human body. The bone marrow tissue in the human body will continuously produce red blood cells, platelets, granulocytes and other blood cells, which do not have corresponding physiological functions after being created, but need to grow and develop continuously. For example, when red blood cells are first produced, they will be stored in the bone marrow tissue in the form of primitive red blood cells, and then continuously develop into early juvenile red blood cells, middle juvenile red blood cells and so on, until they develop into mature red blood cells before they leave the bone marrow tissue and enter the blood circulation. This kind of blood cells, which have just been synthesized by the bone marrow tissue, do not have corresponding physiological functions, and need to develop continuously, are the primitive cells. The number of primitive cells in the normal population is relatively small, generally not more than 5% of the total number of cells in the bone marrow tissue. If the number of primitive cells in the patient’s body is too large, it will inhibit the hematopoietic function of the bone marrow, which will cause the corresponding diseases. At present, if the number of primitive cells in the bone marrow of a patient is greater than or equal to 30% of the total number of nucleated cells in the bone marrow, the patient can be diagnosed as acute leukemia. To summarize, primitive cells are undeveloped blood cells in the human body, which not only do not have physiological functions temporarily, but also cause blood diseases when their number is too high. If a patient is found to have a high number of primitive cells, it is recommended that further examination be conducted to clarify the cause of the disease and treatment be carried out as soon as possible.