Thyroid peroxidase (TPO) is a membrane-bound glycemic protein expressed by thyroid cells. It catalyzes the oxidation of iodide on tyrosine residues in thyroglobulin to form T3 and T4. When the thyroid gland is diseased or the follicular cell structure is damaged, TPO spills into the peripheral bloodstream and acts as an autoimmune antigen to stimulate the body to produce TPOAb.

Thyroglobulin (Tg) is a water-soluble glycoprotein synthesized and secreted by thyroid epithelial cells. It is the main component of thyroid follicular gelatin, which is not abundant in serum, and its main function is to store and synthesize thyroid hormones. In thyroid pathology Tg is secreted or spilled into the blood to induce the body to produce TgAb.

Thyrotropin receptor antibodies (TR-Ab) are antibodies directed against the TSH receptor on the surface of thyroid cells, and are generally divided into two subtypes, thyrotropin receptor-stimulating antibody (TS-Ab) and thyrotropin receptor-blocking antibody (TB-Ab), with TS-Ab being implicated in the pathogenesis of autoimmune hyperthyroidism (Graves' disease), and TB-Ab being implicated in the pathogenesis of autoimmune hypothyroidism (mainly TB-Ab is associated with the development of autoimmune hypothyroidism (mainly Hashimoto's disease).

1. TPO-Ab and Tg-Ab are the main basis for the diagnosis of autoimmune thyroid disease (AITD).

Hashimoto's thyroiditis: significant elevation of TPO-Ab and TG-Ab.

Hyperthyroidism: mildly elevated TPO-Ab, TG-Ab, or elevated TPO-Ab and normal TG-Ab.

Hypothyroidism: TPO-Ab and TG-Ab are elevated and the patient is at risk for hypothyroidism.

Postpartum thyroiditis and infantile hypothyroidism: Pregnant women with persistently positive TPO-Ab and TG-Ab are at higher risk for postpartum thyroiditis and infantile hypothyroidism.

It is generally believed that the sensitivity and specificity of TPO-Ab is better than that of TG-Ab. In order to improve the positive detection rate, the combination of the two antibodies is usually adopted in clinical practice.

2. TR-Ab can be an important basis for the diagnosis of Graves' disease.

3. TR-Ab can be used to determine the efficacy of antithyroid drugs and the risk of recurrence of hyperthyroidism.

Diagreat has now launched Anti-TG test kit (chemiluminescent immunoassay) and Anti-TPO test kit (chemiluminescent immunoassay), which can be used for the diagnosis of autoimmune thyroid diseases.