Thyroid-Stimulating Hormone (TSH) Test: About This Test

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Picture of the thyroid gland

What is it?

A thyroid-stimulating hormone (TSH) test is one of several blood tests used to check for thyroid gland problems. TSH causes the thyroid gland to make other important hormones that help control your body's metabolism.

Why is this test done?

This test is done to:

  • Find out whether the thyroid gland is working properly.
  • Find out if a problem with the thyroid is causing symptoms such as tiredness, weight gain, or weight loss.
  • Keep track of how well thyroid treatment is working.

How can you prepare for the test?

  • In general, you don't need to prepare before having this test. Your doctor may give you some specific instructions.

What happens during the test?

  • A health professional takes a sample of your blood.

What else should you know about the test?

  • This test may be done at the same time as tests to measure other thyroid hormones.
  • Your results will include an explanation of what a "normal" result is. This is called a "reference range." It is just a guide. Your doctor will evaluate your results based on your health and other factors. This means that a value that falls outside the normal values listed may still be normal for you.

How long does the test take?

  • The test will take a few minutes.

What happens after the test?

  • You will probably be able to go home right away.
  • You can go back to your usual activities right away.

Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor or nurse call line if you are having problems. It's also a good idea to keep a list of the medicines you take. Ask your doctor when you can expect to have your test results.

Where can you learn more?

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