What are the thyroid triads?

Thyroid 3 mainly refers to free t3, free t4 and TSH. Free t3 and free t4 are secreted by the thyroid gland and belong to the active part of thyroid hormone, which can directly and accurately judge the function of thyroid gland. Free t3 and free t4 are biologically active and relatively stable in blood because they are active parts of thyroid hormone. They are not affected by TBG and iodine impurities in blood, so they can be measured on a non-fasting basis. TSH is secreted by pituitary gland, which can be stimulated by TRH in hypothalamus and also inhibited by t3 and t4 feedback in serum. It is the best single screening test for thyroid function at this stage.