Follicle-Stimulating Hormone
Does this test have other names?
FSH
What is this test?
This test measures the level of follicle-stimulating hormone (FSH). FSH is an important hormone made in your pituitary gland.
Hormones are chemical messengers that travel through your blood. Your pituitary gland is located on the underside of your brain. FSH is made in the front part of your pituitary gland. The part of your brain that tells the pituitary to make FSH is called the hypothalamus.
FSH travels to the testicles to tell the cells in the testicles to make sperm. FSH travels to the ovaries to stimulate the growth of eggs during the menstrual cycle. FSH is also important for sexual development in children.
Why do you need this test?
You may need this test to find out if your pituitary gland is making too much or too little FSH. This test can help your doctor tell whether problems you may be having are caused by your hypothalamus, pituitary gland, or by your ovaries or testicles. Some conditions that may be checked with this test include:
What other tests might you have along with this test?
Your doctor may also order a blood test that measures another pituitary hormone called luteinizing hormone (LH). LH is also important for normal function of your testicles or ovaries. You may also have tests to measure other hormone levels.
What do your test results mean?
Test results may vary depending on your age, sex, 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 doctor what your test results mean for you.
FSH is measured in milli-international units per milliliter (mIU/mL). Normal results of this test for men are:
If you are a woman, the normal results depend on where you are in your menstrual cycle. Your doctor will help you understand the results. Normal results are:
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1.4 to 9.9 mIU/mL (follicular phase)
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6.2 to 17.2 mIU/mL (ovulatory peak)
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1.1 to 9.2 mIU/mL (luteal phase)
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19.3 to 100.6 mIU/mL after menopause
If this test is done for your child, a normal result will depend on how the test was done and what units of measurement were used.
Many conditions can cause your FSH to be too high or too low. Your doctor will talk with you about the results of your blood test and whether you need more testing.
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 your test results?
Being pregnant or taking birth control pills may affect the results of this test. Some medicines may also affect the results.
How do you get ready for this test?
You don't need to prepare for this test. But be sure your doctor knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illegal drugs you may use.