Patients with iron deficiency anemia should look at the routine blood count of hemoglobin, mean red blood cell volume, mean red blood cell hemoglobin volume, and mean red blood cell hemoglobin concentration. Patients with iron deficiency anemia will suggest a significant decrease in all four of these indicators, which is clinically known as microcytic hypochromic anemia, and its common disease is iron deficiency anemia. However, in addition to iron deficiency anemia, it can also be seen in thalassemia, chronic disease anemia, and iron granulocytic anemia. Therefore, if the blood test indicates microcytic hypochromic anemia, it is necessary to further improve the anemia index and other related tests to clarify whether it is iron deficiency anemia. If the diagnosis is iron deficiency anemia then iron supplementation therapy is needed as well as finding and removing the cause of iron deficiency.