Thyroid Blood Tests

In this Article

• Introduction
• What are thyroid hormones?
• Thyroid hormone regulation -- the chain of command
• How is hypothyroidism diagnosed?
• How is hyperthyroidism diagnosed?
• Are there other tests of the thyroid gland?
• Patient Discussions: Thyroid Blood Tests - Helped With Your Diagnosis

Are there other tests of the thyroid gland?

The blood tests mentioned above can confirm the presence of deficiency or an excess of thyroid hormone and, therefore, be used to diagnose hypothyroidism or hyperthyroidism. They do not point to a specific cause. In order to determine a cause of the thyroid abnormality, the doctor will consider the patient's history, physical examination, and medical condition. Further testing might be used to isolate an underlying cause. These tests might include more blood testing for thyroid antibodies, nuclear medicine thyroid scanning, ultrasound of the thyroid gland, or others.

If thyroid cancer is suspected and surgery may be required, your physician may ask for a blood test known as thyroglobulin. Thyroglobulin is a protein made only by thyroid cells. If the thyroglobulin level at baseline is detectable or elevated (this means the gland does in fact make the protein) it can be used as a tumor marker. After a total thyroidectomy for cancer (removal of the entire thyroid gland) the level should fall to an undetectable range since the cells that make thyroglobulin have been removed. If the level remains detectable after surgery, there is a possibility of thyroid tissue elsewhere in the body, and metastatic disease should be considered. If the level is undetectable for a period of time after surgery and then starts to climb, a recurrence of the cancer - either at the primary site or elsewhere in the body should be considered.

Thyroid Blood Tests - Helped With Your Diagnosis

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