Thyroid Function Tests

Also known as: thyroid blood tests, thyroid tests, T3, T3RU, T4, TSH

What are thyroid function tests?

If doctors suspect a problem with the function of the thyroid gland, such as hypothyroidism, hyperthyroidism or another medical condition, they may recommend thyroid function tests. These are simply a series of blood tests that determine how well the thyroid gland is functioning.

What happens during the test?

The blood test performed for a thyroid function test is similar to most other blood tests. Your health care professional will tie a band of rubber around your upper arm and then draw the blood from a vein in your arm. The blood is then collected and sent to a laboratory for further testing and analysis.

Is any special preparation needed?

You may need to stop taking certain medications prior to the blood test, but typically no special preparation is needed.

What are the risk factors?

Infection, bleeding, or swelling at the injection site are all potential risks.

Reviewed by: Alejandro Diaz, MD

This page was last updated on: June 14, 2022 10:35 AM