Testosterone

• delayed or precocious (early) puberty in boys;
• decreased sex drive in men and women;
• erectile dysfunction in men;
• infertility in men and women;
• testicular tumors in men;
• hypothalamus or pituitary disorders; and
• hirsutism and virilization in girls and women.

• Delayed development of muscle mass
• Lack of deepening of the voice or growth of body hair
• Slow or delayed growth of testicles and penis

A delay can occur if the testes do not produce enough testosterone or if the pituitary does not produce enough LH. 

The test also can be ordered if a young boy seems to be undergoing a very early (precocious) puberty with obvious secondary sex characteristics. Causes of precocious puberty in boys, due to increased testosterone, include various tumors and congenital adrenal hyperplasia.

In men, the test may be ordered when infertility is suspected or if the patient has a decreased sex drive or erectile dysfunction, all of which can result from low testosterone levels. Some other symptoms include lack of beard and body hair, decreased muscle mass, and development of breast tissue (gynecomastia).

In females, testosterone testing may be done if a patient has irregular or no menstrual periods (amenorrhea), 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 tumors that develop in either the ovary or adrenal gland or because of other conditions, such as polycystic ovarian syndrome (PCOS).

• hypothalamic or pituitary disease
• genetic diseases which can cause decreased testosterone production in young men (Klinefelter’s, Kallman’s, and Prader-Willi syndromes) or testicular failure and infertility (as in myotonic dystrophy, a form of muscular dystrophy)
• impaired testosterone production because of acquired damage to the testes, such as alcoholism, physical injury, or viral diseases like mumps.

Increased testosterone levels in males can indicate:

• testicular tumors
• adrenal tumors that are producing testosterone
• use of androgens (also called anabolic steroids)
• early puberty of unknown cause in boys
• hyperthyroidism
• congenital adrenal hyperplasia

In women, testosterone levels are normally low. Increased testosterone levels can indicate:

• PCOS
• ovarian or adrenal gland tumor
• congenital adrenocortical hyperplasia

Prostate cancer responds to androgens, so many men with advanced prostate cancer receive drugs that lower testosterone levels.

Drugs such as anticonvulsants, barbiturates, and clomiphene can cause testosterone levels to rise. Women taking estrogen therapy may have increased testosterone levels.