Erythrocyte distribution width is a parameter that reflects the heterogeneity of erythrocyte volume obtained by instrumental measurements and is an objective indicator of the unequal size of erythrocytes. The high coefficient of variation of erythrocyte distribution width, which generally means more than 16%, indicates that the morphology and volume of erythrocytes vary in size, and some erythrocytes may have a large volume while others have a small volume, which can be caused by megaloblastic anemia, iron deficiency anemia, myelodysplastic syndrome, etc. The specific analysis is as follows: 1. megaloblastic anemia: also known as pernicious anemia, is due to the lack of folic acid and vitamin It is caused by the abnormal hematopoiesis due to the lack of folic acid and vitamin B12 in the body, and the red blood cells become megaloblastic and increase in size, which leads to the high coefficient of variation of red blood cell distribution width. Patients are advised to supplement folic acid and vitamin B12 in time to relieve anemia symptoms. 2. Iron deficiency anemia: Patients with this disease have less iron in their bodies, depletion of stored iron, corresponding reduction of hemoglobin synthesis in their bodies, and smaller red blood cell volume, which leads to high variation coefficient of red blood cell distribution width. Patients can take iron supplements and diet to correct the symptoms of anemia; 3. Myelodysplastic syndrome: It is a malignant blood disease of hematopoietic stem cells, which cannot produce normal blood cells due to the hematopoietic dysfunction of bone marrow. Patients are advised to undergo timely treatment to improve the bone marrow hematopoietic function. For patients with a high erythrocyte distribution coefficient, it is recommended that a detailed examination be performed at a hospital to determine the cause of the disease before treatment is administered.