Test Overview A testosterone test checks the level of this male hormone (androgen) in the blood. Testosterone affects sexual features and development. In men, it is made in large amounts by the testicles adrenal glands ovaries
The pituitary gland luteinizing hormone (LH)
Before puberty sperm
In women, the ovaries account for half of the testosterone in the body. Women have a much smaller amount of testosterone in their bodies compared to men. But testosterone plays an important role throughout the body in both men and women. It affects the brain, bone and muscle mass, fat distribution, the vascular system, energy levels, genital tissues, and sexual functioning.
Most of the testosterone in the blood is bound to a protein called sex hormone binding globulin (SHBG). Testosterone that is not bound ("free" testosterone) may be checked if a man or a woman is having sexual problems. Free testosterone also may be tested for a person who has a condition that can change SHBG levels, such as hyperthyroidism or some types of kidney diseases.
Total testosterone levels vary throughout the day. They are usually highest in the morning and lowest in the evening.
Why It Is Done
A testosterone test may be done to:
See why a man is having problems in fathering a child (infertility). A low amount of testosterone can lead to low sperm counts. Check a man's sexual problems. Having a low level of testosterone may lower a man's sex drive or not allow him to have an erection (erectile dysfunction). See whether a high level of testosterone is causing a boy younger than age 10 to have early signs of puberty. Find out why a woman is developing male features, such as excessive facial and body hair (hirsutism) and a deep voice. Find out why a woman is having irregular menstrual periods. See if testosterone-lowering medicines are working in a man with advanced prostate cancer Find the cause of osteoporosis How To Prepare
In general, there's nothing you have to do before this test, unless your doctor tells you to.
Your doctor may want you to do a morning blood test. That's because testosterone levels are highest between 7 a.m. and 9 a.m.
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How It Is Done
A health professional uses a needle to take a blood sample, usually from the arm.
Watch How It Feels
When a blood sample is taken, you may feel nothing at all from the needle. Or you might feel a quick sting or pinch.
Risks
There is very little chance of having a problem from this test. When a blood sample is taken, a small bruise may form at the site.
Results
Your doctor will have your test results in a few days.
Normal Each lab has a different range for what's normal. Your lab report should show the range that your lab uses for each test. The normal range is just a guide. Your doctor will also look at your results based on your age, health, and other factors. A value that isn't in the normal range may still be normal for you.
High values In men, a high level of testosterone may be caused by cancer of the testicles adrenal glands In boys younger than 10, a high level of testosterone may mean early (precocious) puberty, a tumour in the testicles, or an abnormal adrenal gland. In women, a high level of testosterone may be caused by cancer of the ovaries or adrenal glands or by polycystic ovary syndrome luteinizing hormone (LH) Low values In men or boys who have gone through puberty, a low level of testosterone may be caused by a problem with the testicles, such as slow development of, an injury to, or a lack of testicles. It can also be caused from treatment with the female hormone estrogen, a problem with the pituitary gland A low testosterone level in men can also be caused by certain inherited diseases (such as Klinefelter syndrome or Down syndrome), liver disease (cirrhosis), or treatment for cancer of the prostate gland. Long-term (chronic) alcohol use can cause a low testosterone level. In women, a low level of testosterone may be caused by an underactive pituitary gland, Addison's disease Being very overweight, having long-term (chronic) pain, or taking some pain medicines can lower the level of sex hormone binding globulin (SHBG). This also decreases total testosterone level. Related Information
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Current as of: April 30, 2024
