Test guide
Thyroglobulin
A thyroglobulin test measures the amount of a protein called thyroglobulin (Tg) in a sample of your blood. Your thyroid (a small, butterfly-shaped gland in your neck) makes thyroglobulin along with many other important hormones . Together, these hormones control bodily activities such as your heart rate and how fast you burn calories from food.
What it is for
Though a thyroglobulin test alone cannot be used to diagnose cancer, it can give you and your provider valuable information about any thyroid cancer you already have. For example, a thyroglobulin test can help your provider: Your provider may also order a thyroglobulin test to diagnose and monitor other, noncancerous conditions such as hyperthyroidism and hypothyroidism. In rarer cases, a thyroglobulin test can see if there is any inflammation in your thyroid that’s been caused by a viral infection , such as COVID-19 . Source: MedlinePlus, National Library of Medicine. Medical test information is public domain. Source identity and definition checked automatically on 2026-10-18. No individual clinical interpretation or human reviewer is asserted.
Limitations
Reference intervals and interpretation depend on the laboratory, specimen, method and clinical context. This source definition is educational information; it does not establish a diagnosis, product approval or suitability for an individual.
Also known as
- Tg, TGB, thyroglobulin tumor marker
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