Overview & Description
This is a blood test that measures the amount of follicle-stimulating hormone (FSH) produced by the pituitary gland.
Who is a candidate for the test?
Fertility in men and women, as well as menstruation in women, are regulated by a complex interaction of hormones. The ovaries, pituitary gland, and hypothalamus produce these hormones. Follicle-stimulating hormone, or FSH, causes the follicles within the ovaries to mature.
FSH levels may be measured if the healthcare provider suspects a problem with:
menopause, a time in life when menstruation stops
ovarian cysts, which are fluid-filled sacs on the ovary
precocious puberty, or puberty that happens at an abnormally young age
delayed puberty, or puberty that hasn't occurred by the time it should
female infertility, or inability to become pregnant
male infertility, or the inability to impregnate a woman
anovulatory bleeding, which is abnormal vaginal bleeding not related to a regular menstruation cycle
amenorrhea, or the absence of menstruation
testes that are absent or abnormally small
How is the test performed?
A blood sample is taken from a vein on the forearm or hand. First, the skin over the vein is cleaned with an antiseptic. Next, a strong rubber tube, or "tourniquet," is wrapped around the upper arm. This enlarges the veins in the lower arm by restricting blood flow through them. A fine needle is gently inserted into a vein, and the tourniquet is removed. Blood flows from the vein through the needle, and is collected in a syringe or vial. After the needle is withdrawn, the puncture site is covered for a short time to prevent bleeding. The blood sample is sent to the laboratory to determine the amount of FSH circulating in the blood.
Preparation & Expectations
What is involved in preparation for the test?
There is generally no preparation for this test. However, the healthcare provider may want to have the test done during a particular time of a woman's menstrual cycle.
Results and Values
What do the test results mean?
Normal values depend upon the sex of the person and other factors. Greater than normal levels of FSH may be found in the following conditions:
polycystic ovary disease, a condition that causes ovarian cysts and menstrual cycle problems or irregularities
premature ovarian failure, which may be genetic or related to radiation exposure
Klinefelter syndrome, a genetic disorder that causes testicular failure
Turner syndrome, a genetic disorder in which the ovaries fail to respond to pituitary hormones
absence of the testes
Lower than normal levels may be seen with:
a poorly functioning hypothalamus
some cases of infertility
anorexia nervosa, an eating disorder
exercise-induced amenorrhea, a condition in which a woman stops menstruating after she over-exercises
bulimia nervosa, an eating disorder with overeating followed by induced vomiting
use of oral contraceptive pills or other medications