Thyroglobulin antibodies (anti-Tg)

What it measures

Anti-Tg antibodies are directed against thyroglobulin. They support a diagnosis of autoimmune thyroiditis and must always be measured with thyroglobulin in thyroid cancer follow-up because they interfere with the Tg assay.

Specimen and preparation

• Specimen: Serum or lithium-heparin plasma
• Tube: Gold top

Reference range

Reference ranges differ between laboratories, methods and populations. Always use the range printed on your own lab report.

Causes of high values

• Hashimoto thyroiditis
• Graves disease
• Differentiated thyroid cancer (rising levels may signal recurrence)

Method

Chemiluminescent immunoassay

Good to know

Positive anti-Tg can cause falsely low thyroglobulin results on immunometric assays.

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