What tests are included in thyroid function examination?

Generally, thyroid function tests include thyroid-stimulating hormone (TSH), thyroxine (T4), triiodothyronine (T3), thyroid peroxidase antibodies (TPOAb), and thyroglobulin antibodies (TgAb). If necessary, these tests should be performed under a doctor's guidance. Detailed explanations are as follows:

1. Thyroid-Stimulating Hormone (TSH)

Secreted by the pituitary gland, TSH primarily regulates the proliferation of thyroid cells, thyroid blood supply, and the synthesis and secretion of thyroid hormones. It is the most sensitive indicator for reflecting thyroid function.

2. Thyroxine (T4)

Thyroxine, also known as tetraiodothyronine, is a thyroid hormone secreted by thyroid follicular cells, including total thyroxine and free thyroxine. T4 levels increase in hyperthyroidism and decrease in hypothyroidism.

3. Triiodothyronine (T3)

Triiodothyronine is divided into total triiodothyronine (TT3) and free triiodothyronine (FT3). In hyperthyroidism, both TT3 and FT3 significantly increase. Moreover, during the early stages or initial recurrence of hyperthyroidism, T3 levels may rise earlier than T4 levels.

4. Thyroid Peroxidase Antibodies (TPOAb)

TPOAb is an autoantibody mainly produced by thyroid follicular epithelial cells. Elevated TPOAb levels are commonly seen in autoimmune thyroid diseases, such as Hashimoto's thyroiditis and Graves' disease.

5. Thyroglobulin Antibodies (TgAb)

TgAb is also an autoantibody that primarily targets thyroglobulin. Elevated TgAb levels are similarly common in autoimmune thyroid diseases, such as Hashimoto's thyroiditis and diffuse toxic goiter (Graves' disease). Combined testing with TPOAb offers higher diagnostic value for autoimmune thyroid diseases.

Individuals undergoing thyroid function tests should maintain a regular作息 schedule in daily life and avoid staying up late.