FSH Test

What is the FSH test?

The FSH test measures the level of a substance called follicle stimulating hormone (FSH) in your blood. This hormone is made by the pituitary gland in your brain. FSH helps control a woman’s menstrual cycle. It also controls production of eggs by the ovaries. In men FSH helps control the production of sperm.

Why is this test done?

The FSH test is usually done to help diagnose problems with sexual development, menstruation, and fertility. The test may be used to help diagnose:

• menopause
• polycystic ovary disease, ovarian cysts, irregular vaginal bleeding, or infertility
• sexual development at a very young age
• some testicle problems, like missing or underdeveloped testicles.

How do I prepare for this test?

You may need to avoid taking certain medicines before the test because they might affect the test result. Make sure your healthcare provider knows about any medicines, herbs, or supplements that you are taking. Don't stop any of your regular medicines without first consulting with your healthcare provider.

How is the test done?

A small amount of blood is taken from your arm with a needle. The blood is collected in tubes and sent to a lab.

Having this test will take just a few minutes of your time.

How will I get the test result?

Ask your healthcare provider when and how you will get the result of your test.

What does the test result mean?

The normal range of FSH depends on your age and sex and can vary a lot from lab to lab.

Other hormone tests may be done with the FSH test. The results of the different tests may need to be interpreted together to make a diagnosis.

In women the blood level of the hormone estradiol is measured with FSH. (Estradiol is a type of estrogen. Estrogens are hormones responsible for the growth and functioning of a woman's reproductive system.)

• The level of FSH is high and the level of estradiol is low during and after menopause.
• FSH and estradiol levels are higher than normal if a woman has ovarian cancer or adrenal cancer.
• High levels of FSH and estradiol may be caused by hormone therapy.
• Both the FSH and estradiol levels are higher than normal in girls who have started puberty at a very young age.
• FSH and estradiol levels are low in women who have anorexia.
• FSH and estradiol levels are low if the parts of the brain that control hormones (the pituitary gland and hypothalamus) are not working normally.
• FSH is high and estradiol is low if a woman has Turner's syndrome (a genetic problem).

In men, the blood level of the hormone testosterone is measured with FSH.

• The FSH and testosterone levels are both low if a man's pituitary gland is not making enough hormones. These hormones may also be low if the hypothalamus is not working normally.
• The FSH and testosterone levels are higher than normal if a man is being treated with hormones for a medical condition.
• FSH and testosterone levels are high in boys who have started puberty at a very young age.
• The FSH level is higher than normal and the testosterone level is lower than normal if a man has Klinefelter's syndrome (a genetic abnormality), if his testicles have been removed, and if he has gone through male menopause.

There are many other reasons why FSH test results may be outside the normal range. Sometimes the results vary with recent activity or diet. At other times the way the sample is collected or stored can affect the results. If you are concerned about your lab results, talk to your healthcare provider.

What if my test results are not normal?

Test results are only one part of a larger picture that takes into account your medical history and current health. Sometimes a test needs to be repeated to check the first result. Talk to your healthcare provider about your result and ask questions. Ask if and when you need more tests.