Information about a laboratory test

High Anti-Tg (TgAb): What Does It Mean?

High Anti-Tg may occur in autoimmune thyroid disease and can interfere with thyroglobulin measurement.

Test summary

Test name
Anti-Tg (TgAb)
Abbreviations
TgAb, Anti-Tg
Category
Endocrinology / Thyroid Autoimmunity
Panel
Thyroid Antibody Tests
Specimen
Serum / plasma
Common units
IU/mL, kIU/L

What does the test measure?

Measures antibodies directed against the thyroid protein thyroglobulin.

Why is the test ordered?

Used in evaluating autoimmune thyroid disease and in interpreting thyroglobulin testing.

Information about a low result

Negative Anti-Tg does not completely exclude autoimmune thyroid disease.

Information about a high result

High Anti-Tg may occur in autoimmune thyroid disease and can interfere with thyroglobulin measurement.

Reference and clinical context

Use the reference interval printed on your own laboratory report first. Hormone results may vary with the assay, age, sex, pregnancy, menstrual-cycle phase, and sampling time.

Reference ranges may vary by laboratory, method used, age, sex, pregnancy status, and clinical context. The reference range on your own laboratory report takes precedence.

Interpretation notes

When thyroglobulin is used after thyroid-cancer treatment, Anti-Tg status is particularly important; assay method and using the same laboratory also matter.

Related specialties

  • Endocrinology
  • Internal Medicine
  • Nuclear Medicine
  • Medical Oncology

Frequently asked questions

Sources

  1. Hashimoto's Disease — National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

    U.S. government medical reference · 2026 · Hashimoto disease; TSH/T4/T3 and TPO antibody context · Verified: Aug 11, 2026

  2. Thyroid Antibodies — U.S. National Library of Medicine (MedlinePlus)

    Government medical reference · 2023 · TPOAb, TgAb and TRAb; autoimmune-thyroid context · Verified: Aug 11, 2026

  3. Thyroglobulin — U.S. National Library of Medicine (MedlinePlus)

    Government medical reference · 2026 · Thyroglobulin follow-up after thyroid-cancer treatment; method and anti-Tg interference · Verified: Aug 11, 2026