Thyroglobulin Level
- Sample Type
- Serum
- Fasting
- No
- Unit
- ng/mL
Function
Thyroglobulin (Tg) is a protein produced only by thyroid follicular cells. It serves as the substrate for thyroid hormone synthesis. In healthy individuals, small amounts of Tg leak into the bloodstream.
Why it is Ordered
The primary use of this test is as a tumor marker for patients diagnosed with differentiated thyroid cancer (papillary or follicular). After a total thyroidectomy and/or radioactive iodine ablation, Thyroglobulin levels should be undetectable or very low.
Associated Conditions
- Thyroid Cancer Monitoring: Post-operative rising levels suggest recurrence or metastasis.
- Thyroiditis: Inflammation of the thyroid can cause a temporary spike in Tg levels.
- Graves' Disease: Hyperthyroidism often results in elevated Tg.
- Factitious Thyrotoxicosis: Used to distinguish between thyroid hormone ingestion (low Tg) and endogenous overproduction (high Tg).
Check Your Result
Check Your Result
Enter your lab result to see where you stand compared to the standard reference range.
Why Context Matters
The most significant confounding factor is the presence of Thyroglobulin Antibodies (TgAb), which are found in 15-20% of thyroid cancer patients. TgAb can interfere with the assay, leading to falsely low Tg results. Any Tg test must be performed concurrently with a TgAb screen. High doses of Biotin can also interfere with the immunoassay.
Lab ranges are statistical averages, not biological laws. "Normal" for a 20-year-old male isn't normal for a 60-year-old female.
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Medically Reviewed by Dr. Binoy Babu, MBBS
Board Certified Doctor • 10+ Years Clinical Experience
Dr. Babu is a practicing physician dedicated to empowering patients with clear, actionable medical information. He founded 2opi to bridge the gap between complex lab reports and patient understanding, ensuring everyone has access to a reliable second opinion.
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