Low red blood cell volume distribution width needs to be judged according to the specific situation, it may be a normal phenomenon, or it may be caused by iron deficiency anemia, thalassemia and other diseases. 1. Normal phenomenon: If only the red blood cell volume distribution width is low, and other indicators of blood routine are normal, it is generally a normal phenomenon. 2. Iron deficiency anemia: If the volume distribution width of red blood cells is low, accompanied by low hemoglobin, low average hemoglobin of red blood cells and low average red blood cell volume, it is mostly considered to be caused by iron deficiency anemia. 3. Thalassemia: If the width of red blood cell volume distribution is low, and at the same time there are small red blood cells and low pigmentation, then it is considered that it may be related to thalassemia. Low red blood cell volume distribution width generally does not have reference significance, and it is recommended that when low red blood cell volume distribution width occurs, other blood routine results should be checked whether they are normal or not, and the etiology should be determined according to the results of other blood routine tests. It is recommended that the patient should consult a doctor to find out the cause of the disease in time to avoid delaying the treatment.