What does the Thyroglobulin Antibodies test measure?

Why is Thyroglobulin Antibodies measured?

TgAb are measured chiefly in two settings: as a marker of autoimmune thyroid disease, particularly Hashimoto's thyroiditis (usually alongside TPO antibodies), and as a mandatory accompaniment to serum thyroglobulin measurement in differentiated thyroid cancer follow-up, where their presence can render the thyroglobulin result unreliable. They are less sensitive than TPO antibodies for autoimmune thyroiditis but add diagnostic value and are essential context for thyroglobulin interpretation.

Reference ranges

Standard reference

Negative: <4 IU/mL (method-dependent cut-off) # REVIEWER FLAG: TgAb cut-offs are highly assay-dependent and not interchangeable between platforms — reviewer to confirm against Access Medical Laboratories' assay-specific reference and units.

Functional medicine optimal

A negative (undetectable) result is the expected normal; there is no functional target above zero

Units

IU/mL

Reference ranges vary by laboratory and assay platform. Interpret in context of the issuing laboratory's stated range.