Does this test have other names?
TSH, thyrotropin test
What is this test?
This is a blood test that measures your level of thyroid-stimulating hormone (TSH).
Healthcare providers use this test to diagnose problems affecting the thyroid.
Your thyroid is a butterfly-shaped gland near the base of your throat above your collarbones.
The thyroid makes 2 hormones, T3 and T4. These hormones affect your energy levels,
mood, weight, and other important parts of your health.
The pituitary gland in your brain makes a chemical called TSH. TSH triggers your thyroid
to make T3 and T4. When your pituitary gland makes too much or too little TSH, this
can cause your thyroid to be overactive (hyperthyroidism) or underactive (hypothyroidism).
Why do I need this test?
You may need this test if you have symptoms of thyroid problems.
Symptoms of hyperthyroidism include:
Anxiety and mood swings
Weakness in the arms and legs
Low tolerance for heat
Unexplained weight loss
More frequent bowel movements than usual
Eye irritation or bulging eyes, which are symptoms of Graves disease, a common cause
Enlarged breasts and erectile dysfunction in men
Symptoms of hypothyroidism include:
Healthcare providers may also check TSH levels when diagnosing depression and dementia.
What other tests might I have along with this test?
You may have tests to check your levels of:
T4, total and free
T3, total and free
Thyroglobulin, which helps make and store thyroid hormones
TSH receptor-stimulator antibodies, which is used to diagnose Graves disease
Thyroid peroxidase antibodies and antithyroglobulin antibodies, to diagnose Hashimoto
What do my test results mean?
Test results may vary depending on your age, gender, health history, and other things.
Your test results may be different depending on the lab used. They may not mean you
have a problem. Ask your healthcare provider what your test results mean for you.
Low TSH levels may mean you have hyperthyroidism. High TSH levels can mean you have
hypothyroidism. The results of other thyroid tests can help to find the cause.
How is this test done?
The test is done with a blood sample. A needle is used to draw blood from a vein in
your arm or hand.
Does this test pose any risks?
Having a blood test with a needle carries some risks. These include bleeding, infection,
bruising, and feeling lightheaded. When the needle pricks your arm or hand, you may
feel a slight sting or pain. Afterward, the site may be sore.
What might affect my test results?
Some medicines keep the pituitary gland from releasing TSH. These include:
Other medicines and supplements that can affect thyroid tests include:
How do I get ready for this test?
Certain medicines or herbs can affect thyroid test results.
Be sure your healthcare provider knows about all the medicines, herbs, vitamins, and
supplements you are taking. This includes medicines that don't need a prescription
and any illegal drugs you may use.