T3 refers to triiodothyronine, T4 refers to thyroxine, and TSH refers to thyroid stimulating hormone. FT3 refers to free triiodothyronine, FT4 refers to free thyroxine, and TSH refers to free thyroxine. In addition to FT3, FT4 and TSH, sometimes thyroid-related antibodies are also tested, one being anti-thyroglobulin and the other being anti-thyroid peroxidase antibodies. Based on the above tests, we can determine whether the combination is hypothyroidism or hyperthyroidism, and then choose the appropriate medication for treatment based on the indicators.