The reference range of serum thyroglobulin is about 3 to 40 μg/L. Elevated thyroglobulin greater than 500 μg/L can be seen in diffuse toxic goiter, thyroid adenoma, subacute thyroiditis, thyroid cancer and other diseases. Due to different testing methods and reagents, the reference indexes are different in each hospital and need to be analyzed specifically. The normal reference range for serum thyroglobulin is characterized by a strong geographical variation, as serum thyroglobulin concentration is influenced by iodine intake. In areas of inadequate iodine intake, the mean thyroglobulin value and the upper thyroglobulin reference limit may be elevated in the population in relation to the degree of iodine deficiency. When the thyroglobulin test value is elevated and greater than 500μg/L, one should consult a doctor for further diagnosis and targeted treatment in conjunction with clinical manifestations and results of laboratory tests, thyroid ultrasound, thyroid function, etc. Please follow the doctor’s instructions.