Serum ferritin is a form of iron storage in the body, which is an indicator of whether the body is iron deficient or not. Elevated serum ferritin is usually caused by tumors, blood system diseases or infections. When serum ferritin decreases, it is usually caused by low iron content, poor iron absorption or excessive iron loss. 1. Elevated serum ferritin: (1) Cancer: Lung cancer, liver cancer, breast cancer and other cancer tumors will lead to elevated serum ferritin, and the later the stage of cancer, the more serious the disease, the higher the serum ferritin. (2) Blood system diseases: such as aplastic anemia, myelodysplastic syndrome, etc. will lead to elevated serum ferritin. (3) Infections: severe infections can also lead to elevated serum ferritin. 2. Reduced serum ferritin: (1) Low iron content: If the diet is single or picky or partial, it is easy to cause iron deficiency in the body, which will lead to the lowering of serum ferritin. (2) Iron malabsorption: If the lack of gastric acid in the body will affect the absorption of iron, such as chronic gastritis or gastrointestinal dysfunction, etc., will cause a decrease in serum ferritin. (3) Excessive iron loss: mostly due to excessive blood loss, such as excessive menstruation, gastric ulcers, etc., will lead to lower serum ferritin. If you feel unwell, you should go to the hospital in time, and make a clear diagnosis under the guidance of the physician, so as not to delay your condition.