Antithyroglobulin antibody 300IU/ml does not mean serious, the severity needs to be viewed in the context of the patient’s specific situation, if only the antibody is positive and the thyroid function tests are normal, then it is not serious. Antithyroglobulin antibody, abbreviated as TGAb, is one of the common antibodies used to diagnose autoimmune thyroid diseases, which mainly include Hashimoto’s thyroiditis and Graves’ disease. The normal value of thyroglobulin antibody is 0-85IU/ml (specific reference should be made to the value of the local hospital), TGAb300IU/ml suggests that it is autoimmune thyroid disease, but it cannot evaluate the severity of the disease, and the severity of the disease needs to be determined by the value of thyroid stimulating hormone, T3, T4, to determine whether there is hyperthyroidism or hypothyroidism, as well as whether there is any complication, if it is only positive antibody and the thyroid function test is normal, then it is not serious. If the antibody is only positive and the thyroid function is normal, then it is not serious. It is recommended that patients with positive thyroglobulin antibodies receive standardized treatment under the guidance of a doctor.