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.
A blood sample is needed.
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.
When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or a slight bruise. This soon goes away.
In women, FSH helps manage the menstrual cycle and stimulates the ovaries to produce eggs. The test is used to help diagnose or evaluate:
In men, FSH stimulates production of sperm. The test is used to help diagnose or evaluate:
In children, FSH is involved with the development of sexual features. The test is ordered for children:
Normal FSH levels will differ, depending on a person's age and sex.
Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your doctor about the meaning of your specific test result.
High FSH levels in women may be present:
Low FSH levels in women may be present due to:
High FSH levels in men may mean the testicles are not functioning correctly due to:
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.
Veins and arteries vary in size from one person to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.
Other risks associated with having blood drawn are slight, but may include:
Reviewed By: Cynthia D. White, MD, Fellow American College of Obstetricians and Gynecologists, Group Health Cooperative, Bellevue, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.