The thyroid is a butterfly-shaped gland located in the neck just above the sternum (breastbone). It produces hormones that regulate several different body systems. It is like a command center that controls how your body utilizes energy.

Thyroid tests are also known as thyroid function tests and thyroid symptom tests. Thyroid tests are used to diagnose thyroid diseases like:

• Hypothyroidism.
• Hyperthyroidism.
• Graves’ disease.
• Thyroiditis.
• Hashimoto’s disease

Types of thyroid tests

There are many different types of thyroid tests, but they all fall under one of two categories:

• Thyroid blood tests
• Thyroid imaging tests

Thyroid blood tests

Thyroid blood tests check for hormones and proteins such as thyroglobulin and antibodies. It can find out if you have conditions like hyperthyroidism (overactive thyroid) or hypothyroidism (underactive thyroid). There are different types of thyroid blood tests, for measurement of TSH, T3 and T4, and thyroid antibodies.

• TSH measures your thyroid-stimulating hormone. This is the first test that most health care providers usually recommend. Your pituitary gland (a part of your brain) produces TSH, which travels to the thyroid gland, where it stimulates the production of the thyroid hormones, T3 and T4.
• T3 (or free T3) measures the amount of triiodothyronine in the blood. This hormone is one of the two main hormones that the thyroid gland produces.
• T4 (or free T4) measures the amount of thyroxine in the blood. The other primary hormone that your thyroid gland produces is called thyroxine.
• Thyroid antibody tests indicate whether or not your blood contains thyroid antibodies. The presence of thyroid antibodies might indicate you have an autoimmune disorder like Graves’ disease or Hashimoto’s disease.

Thyroid imaging tests

Thyroid imaging tests help find nodules (lumps) in your neck and determine if they’re benign (noncancerous) or malignant (cancerous).

Thyroid imaging tests can give more information about the size, shape, and function of the thyroid gland. After you’ve undergone thyroid blood testing, your health care provider may suggest imaging studies.

Healthcare providers use different types of imaging tests for different reasons:

• Thyroid ultrasound uses sound waves to assess the size, shape, and position of your thyroid gland. During this test, a handheld device is placed against your neck’s skin. Soundwaves are sent from the device through your body, and a receiver interprets the soundwaves as they bounce off the thyroid. Health Care Providers use ultrasound to find lumps (nodules) in your neck.
• Thyroid scans use CT (Computed Tomography) to examine the size and position of the thyroid gland. In most cases, your health care provider will use a contrasting substance to highlight the areas of concern. Contrast substances block the quantity of X-rays that pass through your body and help get detailed images. This involves either an intravenous injection of radioactive iodine or swallowing a capsule before the test. Sometimes health care providers take thyroid scans without contrast material, but this is less common.
• Thyroid uptake tests help determine how well your thyroid is working. 4-6 hours before the test, you will take a small amount of radioactive iodine (in liquid or pill form). When your appointment time comes, you’ll be seated in a chair and your healthcare professional will insert a gamma probe into your neck. A gamma probe is a portable device that measures the amount of iodine your thyroid absorbs from your blood. If your thyroid absorbs a large amount of iodine, it could mean you have hyperthyroidism or Graves’ disease. If your thyroid absorbs a very small amount of iodine, it might indicate hypothyroidism or Hashimoto’s disease.