Thyroglobulin antibodies optimal range and reference range

Compiled by Alina Radu, founder of Sera, from the published sources below · Last reviewed November 9, 2026

Sera's bands for Thyroglobulin antibodies:

  • Optimal 0 – 4 IU/mL (0 – 4 kIU/L); out of range below 0 or above 4 IU/mL.

Evidence grade: Published reference interval. A band that primarily reflects a published adult laboratory or population reference interval. It is not necessarily applicable to every assay or laboratory.

All units

UnitOptimalSufficientOut of range
IU/mL0 – 4—below 0 or above 4
kIU/L0 – 4—below 0 or above 4

No separate Sufficient band is currently defined for this marker.

What the evidence says

The band ends at 4 IU/mL, the positivity cut-off several widely used assays share (Mayo below 4.0, Abbott-based NHS laboratories below 4.11, Labcorp's upper reference limit below 4). It is not universal: other platforms use much higher numbers, so where the report prints a different cut-off, that one applies. Thyroglobulin antibodies also interfere with thyroglobulin measurement, which matters when thyroglobulin is used for thyroid cancer follow-up.

Sources

  • TGAB - Overview: Thyroglobulin Antibody, Serum — Mayo Clinic Laboratories, 2026 · Laboratory / reference-interval sourceReference value below 4.0 IU/mL at all ages. Matches Sera's optimal upper edge of 4, as a positivity cut-off.
  • Anti-Thyroglobulin Antibodies — University Hospitals Birmingham NHS Foundation Trust, 2026 · Laboratory / reference-interval sourcePositive at 4.11 or above and negative below 4.11, sourced to Abbott Diagnostics; the page prints the unit as IU/L. Close to Sera's edge of 4. Page last updated 19 August 2026.
  • Thyroglobulin Antibody — Labcorp, 2026 · Laboratory / reference-interval sourceIn 137 screened samples the 95% upper reference limit was below 4 IU/mL, and Labcorp reports any result above its limit of detection as elevated. Supports 4 as the top of normal and gives no support for an acceptable tier above it.

What ATG (Anti-Thyroglobulin Antibodies) measures

Antibodies that attack thyroglobulin, a protein stored inside the thyroid.

Looked at together with ATPO, this gives a fuller picture of how much autoimmune activity is affecting the thyroid.

Related thyroid health markers

See Thyroglobulin antibodies in the full list of biomarker ranges

About the author

Alina Radu is the founder of Sera and a software engineer. The idea started with her own Hashimoto's tests, scattered across years without the big picture. She is not a clinician: these ranges are compiled from the published sources linked on each page, with every source named. Alina Radu on LinkedIn

This page is a reference for practitioners, not medical advice. Sera's bands are practitioner targets for structured review, not diagnostic thresholds, and Sera does not diagnose or recommend treatment. Read a result alongside the interval printed by the issuing laboratory and the client's history and symptoms. Range set: Sera Production, version 1.0, last reviewed November 9, 2026.