The first step in diagnosing thyroid nodules is a medical history and physical exam. Thyroid nodules often are found during a physical exam or during a CT scan or ultrasound of the neck, chest, or head done for another problem. Most people do not find thyroid nodules on their own, because they are difficult to feel and usually do not cause symptoms.

If your doctor finds a thyroid nodule, he or she may refer you to an endocrinologist for more tests and treatment.

Common tests for people with thyroid nodules are:

• Thyroid-stimulating hormone (TSH) test. This is a blood test to see how well your thyroid gland is working.
• Fine-needle aspiration guided by ultrasound. Material that is removed from the nodule is checked under a microscope for cancer cells. This is a simple procedure that can be done in your doctor's office.
• Thyroid ultrasound. Ultrasound uses reflected sound waves to create a picture of organs and other structures inside your body. Ultrasound cannot show whether a nodule is cancerous, but it can help your doctor:
  • Confirm that you have thyroid nodules if other tests have not been clear.
  • See what is happening to nodules that are not going away.
  • Find your nodule during a thyroid biopsy with a fine-needle aspiration.

Other tests you may have include:

• Thyroid hormone tests. These blood tests are done to see if a nodule is causing your thyroid gland to make too much or too little thyroid hormone.
• Calcitonin test. This test checks your level of a hormone called calcitonin as a way to help find out if you have cancer. This test will probably be done if other people in your family have had thyroid cancer or any other type of cancer of the endocrine glands.
• Thyroid scan. This test uses radioactive material and a camera to see how well your thyroid gland is working and to see if you have hyperthyroidism.

Ongoing exams

If your nodule is not cancerous, your doctor will see you regularly to monitor the size of your nodule. He or she may do other tests, such as checking your thyroid-stimulating hormone (TSH) levels or doing a thyroid ultrasound. If your nodule grows, other tests or surgery may be needed.

If your thyroid gland was removed because of cancer, your doctor may test for thyroglobulin, a protein made by both normal and cancerous cells. High levels of thyroglobulin may mean that the cancer has spread (metastasized) to other parts of your body.