This test measures the level of follicle-stimulating hormone (FSH), 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.
If you are a man, FSH travels to your testicles, where it stimulates cells in your testicles to produce sperm. If you are a woman, FSH travels to your ovaries to stimulate the growth of eggs during your menstrual cycle.
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 pituitary gland or by your ovaries or testicles. Some conditions that may be checked with this test include:
Ovarian failure in women
Testicular failure in men
Early puberty in children
Fertility problems in men and women
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.
Many things may affect your lab test results. These include the method each lab uses to do the test. Even if your test results are different from the normal value, you may not have a problem. To learn what the results mean for you, talk with your health care provider.
FSH is measured in international units per milliliter (IU/mL). Normal results of this test for men are:
1.24 to 7.8 IU/mL
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:
1.68 to 15 IU/mL (follicular phase)
21.9 to 56.6 IU/mL (ovulatory peak)0.
61 to 16.3 IU/mL (luteal phase)
14.2 to 52.3 IU/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 discuss the results of your blood test, what it means in your case, and whether you need more testing.
The test requires a blood sample, which is drawn through a needle from a vein in your arm.
Taking a blood sample with a needle carries risks that include bleeding, infection, bruising, or feeling dizzy. When the needle pricks your arm, you may feel a slight stinging sensation or pain. Afterward, the site may be slightly sore.
Being pregnant or taking birth control pills may affect the results of this test. Several medications may also affect the results.
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 illicit drugs you may use.