THYROGLOBULIN TEST

A thyroglobulin test measures the level of thyroglobulin in a sample of your blood. Thyroglobulin is a protein that your thyroid makes. Your thyroid is a small, butterfly-shaped gland in your neck. It makes hormones that control many activities in your body, including your heart rate and how fast you burn calories from food. A thyroglobulin test is a type of tumor marker test. Tumor markers are substances made by cancer cells and/or by normal cells in response to cancer in your body. Normally, your thyroid releases small amounts of thyroglobulin into your bloodstream. Cells from common types of thyroid cancer (papillary carcinoma and follicular thyroid cancer) also release thyroglobulin. Thyroglobulin testing is not used to diagnose thyroid cancer because other thyroid diseases that aren't cancer can also affect thyroglobulin levels. But the test is useful after treatment for common thyroid cancers to see if the treatment worked. That's because the goal of treatment is to get rid of all thyroid tissue – both healthy cells and cancer cells. So, if treatment is successful, there should be little or no thyroglobulin in your blood. If thyroglobulin levels remain the same or increase, more cancer treatment may be needed.