In males, the test is ordered, often along with the FSH and LH tests, if puberty is delayed or slow in developing. Although there are differences from individual to individual as to when puberty begins, generally by the age of 10 years, there are hormonal and physical manifestations of the onset of puberty in males. Some symptoms of delayed puberty may include:
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).
What does the test result mean? NOTE: This test has no single number that identifies an abnormal result.
Your lab report (see a sample report) should include
a range of numbers (reference range) that identifies what is expected for you based on
your age, sex, and the method used in that laboratory. You can find more information
about expected results at Reference Ranges
and What They Mean. Lab Tests Online strongly recommends that you discuss the meaning of your test results with your doctor.
The normal range for testosterone levels in men is broad and varies by stage of maturity and age. It is normal for testosterone levels to decline as men age. Decreased levels (hypogonadism) in males may be due to:
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:
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.
This article was last reviewed on February 11, 2009.
This page was last modified on May 13, 2009.
The review date indicates when the article was last reviewed from beginning to end to ensure that it reflects the most current science. A review may not require any modifications to the article, so the two dates may not always agree.
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