Description: A Follicle Stimulating Hormone, or FSH, test is a blood test that measures the levels of FSH in the blood. This can be used to diagnose conditions related to the sex organs, early or late puberty, or a condition affecting the pituitary or hypothalamus. It is also used to predict ovulation, evaluate infertility and monitor during infertility treatment. Levels that are out of range can help, along with several other hormone test, to evaluate the cause of irregular menstrual cycles.
Also Known As: Follicle Stimulating Hormone Test, Follitropin Test
Collection Method: Blood Draw
Specimen Type: Serum
Test Preparation: No preparation required
When is a FSH test ordered?
An FSH test may be recommended for a woman if she is having trouble conceiving or has irregular or absent menstrual periods.
When a woman's menstrual cycle has ended or grown erratic, FSH may be ordered to see if she has entered menopause.
When a man's spouse is unable to conceive, when he has a low sperm count, or when he has low muscle mass or diminished sex drive, for example, the test may be ordered.
When a health care provider detects a pituitary issue in a woman or a man, testing may be ordered. Because a pituitary problem can disrupt the production of a variety of hormones, other signs and symptoms may appear in addition to those described above. Fatigue, weakness, unexpected weight loss, and decreased appetite are just a few examples.
When a boy or girl does not seem to be entering puberty at the proper age, FSH and LH may be prescribed. Puberty symptoms include:
- Breast enlargement in young women
- Pubic hair development
- In boys, the testicles and penis grow.
- In girls, menstruation begins.
What does a FSH blood test check for?
FSH is a hormone linked to production and the development of eggs and sperm in both men and women. FSH is measured in the blood.
The pituitary gland, a grape-sized structure near the base of the brain, produces FSH. The hypothalamus in the brain, the pituitary gland, and hormones generated by the ovaries or testicles all work together to control FSH production. The hypothalamus secretes gonadotropin-releasing hormone, which causes the pituitary to secrete FSH and luteinizing hormone, a hormone that is closely related to FSH and is also important in reproduction.
During the follicular phase of the menstrual cycle, FSH increases the growth and maturation of eggs in the ovaries in women. The menstrual cycle is divided into two phases: follicular and luteal, each lasting approximately 14 days. During this follicular phase, FSH triggers the follicle's synthesis of estradiol, and the two hormones collaborate to help the egg follicle develop further. A surge of FSH and luteinizing hormone occurs near the end of the follicular period. Shortly after this burst of hormones, the egg is released from the ovary. The hormones inhibin, estradiol, and progesterone all help the pituitary gland regulate the quantity of FSH released. FSH also improves the ovary's ability to respond to LH.
Ovarian function declines and eventually quits as a woman matures and approaches menopause. FSH and LH levels rise as a result of this.
FSH induces the development of mature sperm in men's testicles, as well as the production of androgen binding proteins. After adolescence, men's FSH levels remain rather steady.
FSH levels rise early after birth in infants and children, then fall to very low levels by 6 months in boys and 1-2 years in girls. Prior to the onset of puberty and the development of secondary sexual characteristics, concentrations begin to rise again.
The production of too much or too little FSH can be caused by disorders affecting the brain, pituitary, ovaries, or testicles, resulting in infertility, irregular menstrual cycles, or early or delayed sexual development.
Lab tests often ordered with a FSH test:
- Sperm Analysis
- Anti-Mullerian Hormone
- Sex Hormone Binding Globulin
Conditions where a FSH test is recommended:
- Pituitary Disorders
- Endocrine Syndromes
How does my health care provider use a FSH test?
There are various applications for the follicle-stimulating hormone test, which is a hormone linked to reproduction and the development of eggs in women and sperm in men.
The test can be used with additional hormone assays including luteinizing hormone, testosterone, estradiol, and/or progesterone in both women and men to help:
- Find out what's causing infertility.
- Diagnose conditions involving ovarian or testicular dysfunction.
- Aid in the diagnosis of diseases of the pituitary or hypothalamus, which can impact FSH production.
FSH levels are also relevant in women for:
- Menstrual irregularities are being investigated.
- Menopause start or confirmation prediction
FSH levels in males are used to determine the cause of a low sperm count.
FSH and LH are used to diagnose delayed or precocious puberty in children. Puberty timing irregularities could indicate a more significant disease involving the hypothalamus, pituitary gland, ovaries, testicles, or other systems. LH and FSH levels can help distinguish between benign symptoms and real disease. Once it's been determined that the symptoms are due to an actual condition, more testing can be done to figure out what's causing them.
What do my FSH test results mean?
FSH test findings are frequently combined with those from other hormone testing, such as LH, estrogens, and/or testosterone.
A high or low FSH level as part of an infertility workup is not diagnostic, but it does provide some insight into the cause. A hormone imbalance, for example, can influence a woman's menstrual cycle and/or ovulation. To make a diagnosis, a doctor will take into account all of the information gathered during the examination.
FSH and LH levels can assist distinguish between primary ovarian failure and secondary ovarian failure.
Primary ovarian failure is associated with high levels of FSH and LH.
Low FSH and LH levels are indicative of secondary ovarian failure caused by a pituitary or hypothalamic issue. Low FSH levels in the blood have been linked to an increased risk of ovarian cancer.
Primary testicular failure causes high FSH levels. As shown below, this can be the result of developmental problems in testicular growth or testicular damage.
Low levels are indicative of pituitary or hypothalamic dysfunction.
Precocious puberty is defined by high levels of FSH and LH, as well as the development of secondary sexual traits at an extremely young age. This occurs far more frequently in girls than in boys. This abnormal development is usually caused by a problem with the central nervous system, which can have a variety of causes.
Normal prepubescent LH and FSH levels in children who are showing signs of pubertal alterations could suggest a syndrome known as "precocious pseudopuberty." Elevated levels of the hormones estrogen or testosterone cause the signs and symptoms.
LH and FSH levels can be normal or below what is expected for a child of this age range in delayed puberty.
We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results.