The average red blood cell HB, i.e. low average red blood cell hemoglobin concentration, is an indicator that does not have much clinical significance. In clinical practice, it needs to be combined with the indicators of hemoglobin, mean red blood cell volume and mean red blood cell hemoglobin volume in blood routine at the same time to make a comprehensive judgment. If there is a decrease in red blood cell count, hemoglobin concentration, mean red blood cell volume, mean red blood cell hemoglobin volume and mean red blood cell hemoglobin concentration, the condition is considered to be a small cell hypochromic anemia, which is commonly associated with iron deficiency anemia and thalassemia. To further clarify the diagnosis, serum iron, total iron binding capacity, ferritin, hemoglobin electrophoresis, and thalassemia gene testing are also required to clarify the diagnosis.