Follicle-stimulating Hormone (FSH) Blood Test

The follicle stimulating hormone (FSH) blood test measures the level of FSH in blood. FSH is a hormone released by the pituitary gland, located on the underside of the brain. If you are a woman of childbearing age, your health care provider may want you to have the test done on certain days of your menstrual cycle.

Why the Test is Performed?

In women, FSH helps manage the menstrual cycle and stimulates the ovaries to produce eggs. The test is used to help diagnose or evaluate:

  • Menopause.
  • Women who have polycystic ovary syndrome, ovarian cysts.
  • Abnormal vaginal or menstrual bleeding.
  • Problems becoming pregnant, or infertility.

In men, FSH stimulates production of sperm. The test is used to help diagnose or evaluate:

  • Problems becoming pregnant, or infertility.
  • Men who do not have testicles or whose testicles are underdeveloped.

In children, FSH is involved with the development of sexual features. The test is ordered for children:

  • Who develop sexual features at a very young age.
  • Who are delayed in starting puberty.

Normal Results

Normal FSH levels will differ, depending on a person’s age and sex.

Male:

  • Before puberty – 0 to 5.0 mIU/mL (0 to 5.0 IU/L).
  • During puberty – 0.3 to 10.0 mIU/mL (0.3 to 10.0 IU/L).
  • Adult – 1.5 to 12.4 mIU/mL (1.5 to 12.4 IU/L).

Female:

  • Before puberty – 0 to 4.0 mIU/mL (0 to 4.0 IU/L).
  • During puberty – 0.3 to 10.0 mIU/mL (0.3 to 10.0 IU/L).
  • Women who are still menstruating – 4.7 to 21.5 mIU/mL (4.5 to 21.5 IU/L).
  • After menopause – 25.8 to 134.8 mIU/mL (25.8 to 134.8 IU/L).

Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Please talk to your doctor about the meaning of your specific test result.

What Abnormal Results Mean?

High FSH levels in women may be present:

  • During or after menopause, including premature menopause.
  • When receiving hormone therapy.
  • Due to certain types of tumor in the pituitary gland.
  • Due to Turner syndrome.

Low FSH levels in women may be present due to:

  • Being very underweight or having had recent rapid weight loss.
  • Not producing eggs (not ovulating).
  • Parts of the brain (the pituitary gland or hypothalamus) not producing normal amounts of some or all of its hormones.
  • Pregnancy.

High FSH levels in men may mean the testicles are not functioning correctly due to:

  • Advancing age (male menopause).
  • Damage to testicles caused by alcohol abuse, chemotherapy, or radiation.
  • Problems with genes, such as Klinefelter syndrome.
  • Treatment with hormones.
  • Certain tumors in the pituitary gland.

Low FSH levels in men may mean parts of the brain (the pituitary gland or hypothalamus) do not produce normal amounts of some or all of its hormones.

High FSH levels in boys or girls may mean that puberty is about to start.

Keywords: Follicle-stimulating hormone blood test; FSH blood test.

* The Content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.