thyroglobulin
Also written as: Tg — thyroglobulin
Large glycoprotein produced by thyroid follicular cells that serves as a tumor marker after thyroidectomy for cancer.
Full Definition
Thyroglobulin is a large glycoprotein (660 kDa) synthesized exclusively by thyroid follicular cells and stored in thyroid follicles as the precursor for thyroid hormone synthesis. In normal physiology, small amounts are released into circulation, but levels become significantly elevated in various thyroid disorders including goiter, hyperthyroidism, and thyroid cancer. Following total thyroidectomy for differentiated thyroid cancer, thyroglobulin serves as an essential tumor marker for detecting recurrent or metastatic disease. Undetectable thyroglobulin levels in the absence of thyroglobulin antibodies indicate successful ablation, while rising levels suggest disease recurrence requiring further investigation.
Usage
Usage note: Commonly abbreviated as Tg; distinguish from thyroglobulin antibodies (TgAb) in documentation.
In Context
- "Thyroglobulin levels remained undetectable eighteen months after total thyroidectomy." — follow-up laboratory report
- "Rising thyroglobulin prompted additional imaging to evaluate for recurrent thyroid cancer." — oncology consultation