FSH
The Test
How is it used?
When is it ordered?
If any or some of these signs appear at a younger than average age or are delayed beyond the expected age range for puberty, it may be an indication of a more serious problem involving the hypothalamus, pituitary, gonads (ovaries or testes) or other systems. The measurement of LH and FSH may differentiate between benign symptoms and true disease. Once it is established that symptoms are a result of true disease, further testing can be done to discern the underlying cause.
What does the test result mean?
Developmental defects:
- Ovarian agenesis (failure to develop ovaries)
- Chromosomal abnormality, such as Turner’s syndrome
- Ovarian steroidogenesis defect, such as 17 alpha hydroxylase deficiency
Premature ovarian failure due to:
- Radiation
- Chemotherapy
- Autoimmune disease
Chronic anovulation (failure to ovulate) due to:
- Polycystic ovary syndrome (PCOS)
- Adrenal disease
- Thyroid disease
- Ovarian tumor
When a woman enters menopause and her ovaries stop working, FSH levels will rise.
Low levels of FSH and LH are consistent with secondary ovarian failure due to a pituitary or hypothalamic problem.
In men, high FSH levels are due to primary testicular failure. This can be due to developmental defects in testicular growth or to testicular injury, as indicated below.
Developmental defects:
- Gonadal agenesis
- Chromosomal abnormality, such as Klinefelters syndrome
Testicular failure:
- Viral infection (mumps)
- Trauma
- Radiation
- Chemotherapy
- Autoimmune disease
- Germ cell tumor
Low levels are consistent with pituitary or hypothalamic disorders.
Normal prepubescent levels of LH and FSH in children exhibiting some signs of pubertal changes may indicate a benign form of precocious puberty with no underlying or discernable cause or may just be a normal variation of puberty.
In delayed puberty, LH and FSH levels can be normal or below what is expected for a youth within the age range of puberty. The test for LH response to GnRH may need to be performed along with other testing to diagnose the reason for the delayed puberty. Some of the causes for delayed puberty can include:
In young children, high levels of FSH and LH and/or development of secondary sexual characteristics at an unusually young age are an indication of precocious puberty. This is much more common in girls than in boys. This premature development can have many different underlying causes that need to be diagnosed and treated. Some of the causes include:
Is there anything else I should know?
If youve recently had a nuclear medicine scan, the radioisotopes used in the scan may interfere with results of the FSH test.
