Thyroglobulin antibodies (anti-TG)

Thyroglobulin antibodies (anti-TG) is a specialised blood test used to detect autoantibodies directed against thyroglobulin, the protein precursor of thyroid hormones. It is primarily requested when autoimmune thyroid disease is suspected, such as Hashimoto's thyroiditis or Graves' disease, and is often performed alongside thyroid function tests and thyroid peroxidase (TPO) antibodies to build a complete picture of thyroid autoimmunity. The test is also valuable in monitoring known autoimmune thyroid conditions over time and in interpreting thyroglobulin tumour marker results in patients with differentiated thyroid cancer, where the presence of anti-TG can interfere with thyroglobulin measurement.

The analysis is carried out using a validated immunoassay technique, typically enzyme-linked immunosorbent assay (ELISA) or chemiluminescent immunoassay (CLIA), depending on the laboratory platform. A simple blood sample is all that is required, and no special preparation is needed.

Biomarkers included

Thyroid Autoantibodies
- Thyroglobulin antibodies (TG Ab)

Why it matters
Anti-TG antibodies are a key marker of autoimmune thyroid activity. Their presence can help confirm an autoimmune cause for an underactive or overactive thyroid, explain subtle or fluctuating thyroid symptoms, and guide long-term monitoring. Because anti-TG can also interfere with thyroglobulin testing in thyroid cancer follow-up, identifying these antibodies ensures results are interpreted correctly and appropriate clinical decisions are made. Testing anti-TG alongside TPO antibodies and thyroid function gives a clearer, more actionable view of thyroid health.

Thyroid Autoantibodies
- Thyroglobulin antibodies (TG Ab)

No special preparation required.

For blood tests, we recommend drinking plenty of water beforehand to ensure smooth sample collection. If you are taking any regular medication, continue to do so unless advised otherwise by your doctor.