The normal reference range of ferritin is 15-200μg/L for adult male serum; 12-150μg/L for adult female serum. when the serum ferritin level is lower than the normal reference value, it is called low ferritin, and the main causes and hazards are as follows: a. Causes of low ferritin: 1. Insufficient iron intake: infants and adolescents are in a critical period of growth and development, and the need for iron is higher The need for iron is high. If the diet is too single, picky and partial, it is easy to cause low ferritin. In addition, women who are pregnant or breastfeeding have a high demand for iron and inadequate supplementation can also lead to low ferritin. Long-term malnutrition, chronic liver disease and other patients due to insufficient iron intake, can also appear low ferritin; 2, iron malabsorption: if the body lack of gastric acid will affect the absorption of iron, such as chronic gastritis, gastrointestinal dysfunction patients can lead to low ferritin; 3, excessive iron loss: mostly due to excessive blood loss, such as excessive menstruation, gastric ulcer, gastrointestinal polyps, esophagogastric fundus The rupture of varicose veins and bleeding can lead to low ferritin. The danger of low ferritin: 1, iron deficiency anemia: low ferritin leads to a decrease in hemoglobin synthesis, which leads to iron deficiency anemia; 2, physical weakness: low ferritin leads to a decrease in the oxygen-carrying capacity of hemoglobin, which can lead to dizziness and weakness, pallor, memory loss, panic and shortness of breath and other physical weakness; 3, body dysfunction: patients with low ferritin may affect the body’s Patients may experience irritability, inattention, dry hair, hair loss, thin and brittle nails, easy to develop keratitis, etc. Some patients may also have difficulty swallowing, atrophy of the tongue papillae, etc.; 4, other: women with low ferritin may experience menstrual disorders. Low ferritin in breastfeeding women may also lead to insufficient milk secretion, affecting the normal growth and development of infants and children.