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Follicle-stimulating Hormone (FSH)
- Pituitary Gonadotropin
Excessive FSH and LH are found in hypogonadism, anorchia, gonadal failure,1 complete testicular feminization syndrome, menopause, Klinefelter syndrome, alcoholism, and castration. FSH and LH are pituitary products, useful to distinguish primary gonadal failure from secondary (hypothalamic/pituitary) causes of gonadal failure, menstrual disturbances, and amenorrhea. Useful in defining menstrual cycle phases in infertility evaluation of women and testicular dysfunction in men. FSH is commonly used with LH, which also is a gonadotropin. Both are low in pituitary or hypothalamic failure. FSH and LH levels are high following menopause.
Secretion of both LH and FSH are pulsatile, in response to the normal intermittent release of gonadotropin-releasing hormone (GnRH). In addition, in females, both FSH and LH vary over the course of the menstrual cycle, with peaks at time of ovulation. Thus, interpretation of a single determination may be difficult. It has been suggested that samples be obtained at 15- to 30-minute intervals and equal volumes of serum be pooled to decrease the effect of pulsatile secretion.
As with all tests containing monoclonal mouse antibodies, erroneous findings may be obtained from samples taken from patients who have been treated with monoclonal mouse antibodies or who have received them for diagnostic purposes.2 In rare cases, interference due to extremely high titers of antibodies to streptavidin and ruthenium can occur.2 The test contains additives, which minimize these effects.
Electrochemiluminescence immunoassay (ECLIA)
Children (Male and Female) (mIU/mL)
8 to 30 d
1 to 12 m
1 to 4 y
5 to 9 y
10 to 12 y
13 to 16 y
Adult Male (mIU/mL): 1.5−12.4
Adult Female (mIU/mL)
FSH is a glycoprotein consisting of two subunits (α- and β-chains). Its molecular weight is approximately 32,000 daltons. FSH together with LH (luteinizing hormone), belongs to the gonadotropin family. FSH and LH regulate and stimulate the growth and function of the gonads (ovaries and testes) synergistically.3
FSH and LH are released in pulses from the gonadotropic cells of the anterior pituitary. The levels of the circulating hormones are controlled by steroid hormones via negative feedback to the hypothalamus. In the ovaries, FSH, together with LH, stimulates the growth and maturation of the follicle and hence also the biosynthesis of estrogens in the follicles.
In women, the gonadotropins act within the hypothalamus-pituitary-ovary regulating circuit to control the menstrual cycle.1,4 The FSH level shows a peak at midcycle, although this is less marked than with LH. Due to changes in ovarian function and reduced estrogen secretion, high FSH concentrations occur during menopause.1 The determination of FSH in conjunction with LH is utilized for the following indications: congenital diseases with chromosome aberrations, polycystic ovaries (PCO), amenorrhea (causes), and menopausal syndrome.
In men, FSH serves to induce spermatogonium development. Determination of the FSH concentration is used in the elucidation of dysfunctions within the hypothalamus-pituitary-gonads system. Depressed gonadotropin levels in men occur in azoospermia.1,3,5,6
0.3 mL (Note: This volume does not allow for repeat testing.)
Red-top tube or gel-barrier tube
If a red-top tube is used, transfer separated serum to a plastic transport tube. Avoid hemolysis.
This test may exhibit interference when sample is collected from a person who is consuming a supplement with a high dose of biotin (also termed as vitamin B7 or B8, vitamin H, or coenzyme R). It is recommended to ask all patients who may be indicated for this test about biotin supplementation. Patients should be cautioned to stop biotin consumption at least 72 hours prior to the collection of a sample.
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