Thyroglobulin Antibody (THYAB)

Background

Thyroglobulin (Tg) is a large glycoprotein (MW 600,000) that is stored in the follicular colloid of the gland. Thyroglobulin functions as a prohormone in the intrathyroid synthesis of T4 and T3. Lysosomes containing proteases cleave T4 and T3 from Tg, resulting in release of these hormomes.

Thyroglobulin is present in the serum of normal healthy individuals and can be elevated in numerous disorders which disrupt thyroid tissue. Elevated circulating levels of Tg have been found in a number of thyroid Conditions including Hashimoto’s disease, Grave’s disease. Thyroid Adenoma, subacute thyroiditis and thyroid carcinoma1.

Thyroglobulin antibodies (TgAb) are often present in patients with autoimmune thyroid disease. Approximately 10% of healthy individuals have TgAb at measurable levels.

TgAb can be detected in 30% of patients with Graves’ disease and in 85% of patients with Hashimoto’s thyroiditis.

In particular sensitive TgAb methods are required to identify patient sera that contain thyroglobulin autoantibodies that may interfere with serum thyroglobulin measurements. This is the reason why TgAb are measured at the JCUH.

Reference ranges

Less than 40.0 IU/mL

Specimen requirements

Sample Type:

Serum

Sample Identification:

Three patient identifiers from
- Name
- D.O.B.
- Address
- N.H.S. number
- Unit Number
should match on the specimen and request form. This check may be performed prior to centrifugation by the Central Sort department.