In boys, the testosterone is measured with the FSH and LH tests, if puberty is delayed or slow in developing. Although puberty begins at different times in different individuals, generally by the age of 10 years, there are hormonal and physical manifestations of the onset of puberty. A delay can occur if the testes do not produce enough testosterone or if the pituitary does not produce enough LH.The test may be performed if a young boy seems to be undergoing a very early (precocious) puberty with obvious secondary sex characteristics, such as an enlarged penis, development of muscle mass, deepening voice and growth of body hair.In men, the test may be performed when infertility is suspected or if the patient has a decreased sex drive or erectile dysfunction, which can result from low testosterone levels.In women, testosterone may be measured if a patient has irregular or no menstrual periods (amenorrhoea), is having difficulty getting pregnant, or appears to have masculine features, such as facial and body hair, male pattern baldness, and a low voice. Testosterone levels can rise because of tumours that develop in either the ovary or adrenal gland or because of other conditions, such as polycystic ovarian syndrome (PCOS).
