Thyroglobulin 5 is a blood test for thyroid function: thyroxine (T4), triiodothyronine (T3), thyroid stimulating hormone (TSH), serum free triiodothyronine (FT3), and serum free thyroxine (FT4). The indicators may vary slightly from hospital to hospital. 1. Thyroxine (T4): is the most basic screening test to determine thyroid function, and the results are affected by changes in the amount and binding capacity of the binding protein. 2. Triiodothyronine (T3): a biologically active thyroid hormone, the results are affected by the binding protein, and its concentration changes are often parallel to that of T4, and it is a specific diagnostic indicator for T3-type hyperthyroidism. 3. Thyroid stimulating hormone (TSH): secreted by the anterior pituitary gland, its physiological function is to stimulate the development of the thyroid gland, promote the synthesis and secretion of thyroid hormone by the thyroid gland, and the result is not affected by the binding protein of thyroid hormone, it is a sensitive indicator reflecting the function of the hypothalamic-pituitary-thyroid axis, and it is especially important for the diagnosis of subclinical hyperthyroidism and subclinical hypothyroidism. 4. Serum free triiodothyronine (FT3): it is not affected by thyroid hormone binding protein, and directly reflects the state of thyroid function; its sensitivity and specificity are significantly higher than that of T3, and it is a sensitive indicator reflecting the function of the thyroid gland. 5. Serum free thyroxine (FT4): also not affected by thyroid hormone binding protein, its sensitivity and specificity are higher than T4. If there is a need for thyroid function test, please go to the local regular hospital to complete the examination and feedback the result to the endocrine specialist for further treatment.