Test Details
Thyroglobulin Antibody (Anti-Tg)
An antibody directed against the thyroid-specific protein thyroglobulin (Tg). Increased antibody levels are often associated with thyroiditis including Hashimotos, Graves, and post-partum thyroditis.
Methodology
Chemiluminescence
Patient Preparation
Preferred Specimen
Green Top Tube
(Lithium Heparin plasma separator tube with gel)
Alternate Specimen
Transport Temperature
Refrigerated (ship on frozen cold packs)
Stability
Refrigerated: 7 days
Lab Values
Thyroglobulin Antibody (Anti-Tg)
- Optimal: ≤60 IU/mL
- Increased Risk: >60 IU/mL
Clinical Significance
Thyroglobulin Antibody (Anti-Tg)
Tg antibodies are mainly used to evaluate a diagnostic suspicion of autoimmune thyroiditis, and are usually requested together with TPO antibodies. Tg antibodies are polyclonal antibodies to Tg with a prevalence of 20%–90% in Hashimoto thyroiditis and 30%–60% in Graves disease, but, like TPO Abs, they are also present in 10%–27% of healthy adults. Tg antibodies are less common and of lower titer than TPO antibodies. The majority of patients with Hashimoto’s thyroiditis have TPO and/or Tg antibodies, such that a negative antibody result has a high negative predictive value. The titer of Tg antibodies does not usually correlate with the degree of thyroid dysfunction.
References:
- Burek CL, Rose NR, Caturegli P. Thyroglobulin, thyroperoxidase, and thyrotropin-receptor autoantibodies. In Autoantibodies (second edition), 2007. Science Direct: https://doi.org/10.1016/B978-044452763-9/50055-X
Treatment Options
Thyroglobulin Antibody (Anti-Tg)
Treatment is based on etiology of elevation and clinical symptoms.
