The items included in the five tests vary from hospital to hospital. In most cases, the tests are total triiodothyronine (total T3), total thyroxine (total T4), free triiodothyronine (free T3), free thyroxine (free T4) and thyroid stimulating hormone (TSH). Some hospitals also test for free triiodothyronine (free T3), free thyroxine (free T4), thyroid stimulating hormone (TSH), anti-thyroid peroxidase autoantibodies (TPOAb) and anti-thyroglobulin antibodies (TGAb). These five tests are used to assess the function of the thyroid gland as well as its secretion. Increased serum total T3 and total T4 values are mainly seen in hyperthyroidism, while decreased values are commonly seen in hypothyroidism and reduced pituitary function. If the levels of free T3 and free T4 in normal serum are low, they can reflect the sensitivity of the thyroid gland. Increased levels can be seen in hyperthyroidism and decreased levels in hypothyroidism; TPOAb and TGAb antibodies represent the presence of autoimmune thyroid disease. If there is an abnormality in the five items of thyroid function, the patient needs to undergo thyroid ultrasound, thyroid ultrasound and other related examinations to clarify the cause of the disease according to the test results, and then carry out targeted treatment. The daily diet is recommended to be light and avoid spicy and stimulating foods to avoid aggravating the symptoms.