A follicle-stimulating hormone test measures
the amount of follicle-stimulating
hormone (FSH) in a blood sample. FSH is produced by
- In women, FSH helps control the
menstrual cycle and the production of eggs by the
ovaries. The amount of FSH varies throughout a woman's
menstrual cycle and is highest just before she releases an egg
- In men, FSH helps control the production of sperm. The
amount of FSH in men normally remains constant.
The amounts of FSH and other hormones (luteinizing hormone,
estrogen, and progesterone) are measured in both a man and a woman to determine
why the couple can't become pregnant (infertility).
The FSH level can help determine whether male or female sex organs (testicles or ovaries) are functioning properly.
Why It Is Done
A follicle-stimulating hormone (FSH)
test may be done to:
- Help find the cause of infertility. FSH testing
is commonly used to help evaluate a:
- Woman's egg supply (ovarian
- Man's low sperm count.
- Help evaluate menstrual problems, such as
irregular or absent menstrual periods (amenorrhea). This can help determine
whether the woman has gone through
- Determine if a child is going
puberty (also called precocious puberty). Puberty is
early when it starts in girls younger than age 9 and in boys younger than age
- Determine why sexual features or organs are not developing when
they should (delayed puberty).
- Help diagnose certain pituitary
gland disorders, such as a tumor.
How To Prepare
Many medicines, such as cimetidine,
clomiphene, digitalis, and levodopa, can change your test results. You may be
asked to stop taking medicines (including birth control pills) that contain
estrogen or progesterone or both for up to 4 weeks
before having a follicle-stimulating hormone (FSH) test. Make sure your doctor
has a complete list of all the prescription and over-the-counter medicines you
are taking, including herbs and natural substances.
doctor if you have had a test that used a radioactive substance (tracer) within
the last 7 days. Recent tests using a radioactive tracer (such as a thyroid
scan or bone scan) can interfere with FSH test results.
doctor know the first day of your last menstrual period. If your bleeding
pattern is light or begins with spotting, the first day is the day of heaviest
Talk to your doctor about any concerns you have
regarding the need for the test, its risks, how it will be done, or what the
results will mean. To help you understand the importance of this test, fill out
medical test information form(What is a PDF document?).
How It Is Done
The health professional drawing your
- Wrap an elastic band around your upper arm to
stop the flow of blood. This makes the veins below the band larger so it is
easier to put a needle into the vein.
- Clean the needle site with
- Put the needle into the vein. More than one needle stick
may be needed.
- Attach a tube to the needle to fill it with
- Remove the band from your arm when enough blood is
- Apply a gauze pad or cotton ball over the needle site as
the needle is removed.
- Apply pressure to the site and then a
For a woman who is having problems with her menstrual cycle
or who cannot become pregnant, more than one blood sample may be needed to help
identify a follicle-stimulating hormone (FSH) problem. A sample may be taken
each day for several days in a row.