Low thyroglobulin is usually not a problem. Thyroid-binding globulin is a large glycoprotein secreted by thyroid follicular epithelial cells, most of which are synthesized by thyroid cells and released into the residual lumen of the thyroid follicle, where its production can be stimulated by thyroid stimulating hormone, iodine deficiency in the thyroid gland, and thyroid stimulating immunoglobulin. Testing for thyroid binding globulin in patients with congenital hypothyroidism can identify complete thyroid deficiency and hypothyroidism. Thyroglobulin is also considered to be a specific marker of morphological integrity of the thyroid body, a tumorigenic marker of differentiated thyroid cancer, and can be used as an important reference indicator for follow-up of patients with differentiated thyroid cancer after treatment, as well as to identify subacute thyroiditis and thyrotoxicosis. It is not clinically significant and does not need to be treated for the time being. Regular review of thyroid function and thyroid ultrasound will be sufficient. The normal reference value of thyroglobulin is 5-40μg/L. If the index is elevated, its clinical significance is mainly as follows: 1. Thyroid disease: it belongs to benign disease, such as hyperthyroidism, toxic nodular goiter, subacute thyroiditis and chronic lymphocytic thyroiditis, all of which can have elevated thyroglobulin; 2. Differentiated thyroid cancer: thyroglobulin is important for thyroid The prognosis of differentiated thyroid cancer and the monitoring of treatment effect are of great significance. Clinical follow-up of patients with differentiated thyroid cancer revealed that the sensitivity of measuring thyroglobulin content to diagnose recurrence or metastasis of differentiated thyroid cancer is 88%-97%, and the specificity is 100%. A high level of thyroglobulin before thyroid cancer surgery suggests that the tumor can produce thyroglobulin. Postoperative thyroglobulin can be used as a sensitive follow-up tumor marker to see if the patient has the possibility of thyroid cancer recurrence after surgery. Serum thyroglobulin measurement is also an objective indicator to evaluate the efficacy of the treatment. 3. Thyroglobulin level is also significantly abnormal in different types of differentiated thyroid cancer. Follicular carcinoma thyroglobulin level is much higher than papillary carcinoma, which is mainly related to the different ability of the two cell types to secrete thyroglobulin, which determines the degree of thyroglobulin decrease after treatment.