Thyroglobulin (Tg) is produced in the thyroid gland and is a main component in

the lumen of the thyroid follicle. In synergy with the enzyme thyroid‐specific

peroxidase (TPO), Tg has an essential function in the iodination of L‐tyrosine and

in the formation of the thyroid hormones T4 and T3. Both Tg and TPO are

potentially autoantigenic.

Elevated serum concentrations of antibodies against Tg (Tg‐autoantibodies) are

found in subjects with autoimmunity‐based thyroiditis. High concentrations of anti‐

Tg together with anti‐TPO are indicative of chronic lymphocytic‐infiltrative

thyroiditis (Hashimoto's disease). The frequency of thyroglobulin antibodies is

approximately 70‐80 % in subjects with autoimmune‐thyroiditis, including

Hashimoto's disease, and approximately 30 % in individuals with Graves'

disease.The anti‐Tg assay is important for use in monitoring the course of

Hashimoto's thyroiditis and for the differential diagnosis (cases of suspected

autoimmune thyroiditis of unknown origin with negative anti‐TPO test results,

Graves' disease without lymphocytic infiltration, and to rule out interference by Tg‐

autoantibodies in the Tg test).

Although the sensitivity of the procedure can be increased by simultaneously

determining additional thyroid antibodies (anti‐TPO, TSH‐receptor‐antibodies), a

negative result does not definitively rule out the presence of an autoimmune

disease. The level of the antibody titer does not correlate with the clinical activity

of the disease. Titers that are elevated initially can become negative if the disease

persists for a longer period of time or if remission occurs. If antibodies reappear

after remission, a relapse is likely.

The Enzyme linked immunosorbent assays uses human antigen and rabbit

antihuman IgG antibodies (anti-IgG).