The most common cause of low erythrocyte mean hemoglobin concentration is anemia, which can be divided into four major categories, including hemorrhagic anemia, hemolytic anemia, abnormal proliferative anemia and hematologic diseases, such as rare leukemia, myeloma, bone marrow cancer or tumors in other areas, which can also cause low erythrocyte mean hemoglobin concentration. The average red blood cell hemoglobin concentration is the most direct manifestation of the hemoglobin concentration in the blood, and usually the most important cause is anemia, as well as bleeding and hemolysis, because the red blood cells are directly lysed away after anemia, bleeding and hemolysis. In addition, abnormal cell proliferative anemia, mainly abnormal proliferative hemoglobinopathy and megaloblastic anemia, and iron deficiency anemia, rare diseases such as leukemia, myeloma, aplastic anemia, and bone marrow infiltration can also cause low erythrocyte hemoglobin concentration, usually below 320 g/L can be diagnosed as low erythrocyte mean hemoglobin concentration.