FSH stands for follicle-stimulating hormone (FSH). This hormone is released by the anterior pituitary gland.

In women, FSH stimulates production of eggs and a hormone called estradiol during the first half of the menstrual cycle.

In men, FSH stimulates production of sperm.

This article discusses the test to check the level of FSH in the blood.

How the Test is Performed

Blood is drawn from a vein, usually from the inside of the elbow or the back of the hand. The site is cleaned with germ-killing medicine (antiseptic). The health care provider wraps an elastic band around the upper arm to apply pressure to the area and make the vein swell with blood.

Next, the health care provider gently inserts a needle into the vein. The blood collects into an airtight vial or tube attached to the needle. The elastic band is removed from your arm.

Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.

In infants or young children, a sharp tool called a lancet may be used to puncture the skin and make it bleed. The blood collects into a small glass tube called a pipette, or onto a slide or test strip. A bandage may be placed over the area if there is any bleeding.

How to Prepare for the Test

If you are a woman of childbearing age, your health care provider may want you to obtain the blood test on certain days of your menstrual cycle.

How the Test Will Feel

When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.

Why the Test is Performed

Your doctor may order this test if you have signs of certain reproductive or pituitary disorders. In some situations, it may also be done to confirm menopause.

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

• Menopause
• Women who have polycystic ovary disease, ovarian cysts, irregular vaginal bleeding, or infertility
• Children who start sexual development at a very young age
• Men who have infertility
• Men who do not have testicles or whose testicles are underdeveloped

Normal Results

Normal FSH levels will differ depending on a person's age and gender.

• Male
  • Before puberty: 0-5.0 IU/L*
  • During puberty: 0.3-10.0 IU/L
  • Adult: 1.5-12.4 IU/L or 5 to 20 mIU/mL
• Female:
  • Before puberty: 0-5.0 IU/L
  • During puberty: 0.3-10.0 IU/L
  • Women who are menstruating: 3.5-3.0 IU/L or 5-20 m U/L
  • Postmenopausal: 40-250 IU/L or 50 mIU/mL to 100 mIU/mL
  • Pregnant women: too low to measure

Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

* IU/L = international units per liter

What Abnormal Results Mean

Disorders that may be associated with abnormal FSH results include:

• Hypopituitarism
• Klinefelter syndrome
• Polycystic ovary disease
• Turner syndrome
• Ovarian failure (ovarian hypofunction)
• Ovarian or adrenal cancers
• Precocious puberty in girls and boys
• Anorexia

The test may also be performed for:

• Anovulatory bleeding
• Multiple endocrine neoplasia (MEN) I
• Ovarian cysts

Risks

Veins and arteries vary in size from one patient 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:

• Excessive bleeding
• Fainting or feeling light-headed
• Hematoma (blood accumulating under the skin)
• Infection (a slight risk any time the skin is broken)

Alternative Names

Follicle stimulating hormone