Low ferritin indicates iron deficiency in the body and is an important manifestation of iron deficiency anemia. Iron is an important raw material for the synthesis of hemoglobin. When the iron content becomes low, the synthesis of hemoglobin will be reduced, and the central light stained area will be enlarged and the cell size will become smaller, which will become microcytic hypochromic anemia. Iron deficiency in the body is first manifested by the depletion of iron stores in the body, and then by the reduction of iron in red blood cells, which eventually leads to the manifestation of iron deficiency anemia. A normal person needs 20-25mg of iron per day for blood production, 80% of which comes from aging red blood cells, 20% from daily food intake, part of which is transported to the bone marrow to synthesize hemoglobin, and the excess iron is combined with transferrin and stored. When the body needs iron and the external supply is not enough time to break down the body’s ferritin, so the decrease in ferritin is a very sensitive indicator of iron deficiency in the body. It is important to note whether the cause of iron deficiency is due to blood loss or not eating enough. If the presence of a bleeding condition is ruled out, you can eat more iron-containing foods, such as lean meat and liver.