The normal value of serum thyroxine is 45～109ng/ml (chemiluminescence method), and the reference value range may be different in different hospitals. 1. Increased thyroxine: it can be seen in painless thyroiditis, subacute thyroiditis, hyperthyroidism, teratoma, malignant chorionic epithelial tumor, pituitary thyroid hormone tumors and other diseases; it can also be seen in pregnancy, newborns and other physiological increase. 2. Reduced thyroxine: mainly seen in chronic thyroiditis, cretinism, iodine organic disorder, pituitary hypothyroidism, hypoproteinemia, cirrhosis and other conditions. When thyroxine is abnormal, you need to go to the regular hospital for consultation.