Thyroid hormones (T4, T3). The two main hormones of the thyroid gland are thyroxine (T4), and triiodothyronine (T3). When these two hormones are released from the thyroid gland into the blood, the vast majority (more than 99%) are bound to specific proteins, and in this bound form they reach all parts of the body with the blood, just like there are some passengers in the blood in a small boat, the small boat is equivalent to these proteins, and the passengers are T4 and T3; the remaining very little The remaining part is not bound to the proteins and is free in the blood, just like the passengers swimming in the blood, these free thyroid hormones are called free T4 and T3 (FT4 and FT3) in the report form. Although small, these free thyroid hormones are very important because they are the only ones that can bind to the receptors on the cells and thus play a physiological role. When free T4 and T3 enter the cells, some T4 and T3 are released from the “ship” to maintain the stability of free T4 and T3 in the blood. Depending on the purpose, sometimes your doctor will test for total T4 or total T3 levels in your blood (he means all the T4 and T3 in your blood, whether bound to protein or not), and sometimes he will test for free T4 or free T3 levels. TSH is a hormone secreted by the pituitary gland that works to stimulate the thyroid cells, and its results reflect whether the feedback mechanisms between the thyroid and the brain are functioning properly. normal. If thyroid hormones are below normal, TSH will generally rise above the normal range to stimulate the thyroid gland to produce more thyroid hormones (T4 and T3). Similarly, assuming you have a history of thyroidectomy and are taking medications to supplement your thyroid hormones, if your TSH level is above the normal range at this time, it means that your thyroid intake may be inadequate. Thyroglobulin. (Tg) It is produced by the thyroid gland alone, but it is not a hormone. The thyroid hormones in the thyroid gland are stored in thyroglobulin. The thyroid gland does not actively release them into the bloodstream, but some thyroglobulin is always “leaked” into the bloodstream. For patients with well-differentiated thyroid cancer, thyroglobulin is one of the most important tests. Elevated thyroglobulin in the blood of patients who have undergone surgery and radioactive iodine therapy also indicates the presence of residual thyroid cancer cells. Anti-thyroglobulin antibodies. These are produced by lymphocytes in the body’s immune system and can interact with thyroglobulin. These antibodies are most commonly seen in patients with autoimmune diseases such as Hashimoto’s disease or Hashimoto’s thyroiditis, which gradually damage thyroid cells and eventually lead to destruction of thyroid tissue. Many patients have anti-thyroglobulin antibodies that disappear after treatment for thyroid cancer (which may take months or even years), while some patients have antibodies that do not disappear, meaning they have had Hashimoto’s disease or have residual cancer cells; if the antibodies disappear and then reappear, it is a sign that new cancer cells may have grown.