A testosterone test measures the amount of the male hormone, testosterone, in the blood. Both men and women produce this hormone.
The test described in this article measures the total amount of testosterone in the blood. Much of the testosterone in the blood is bound to a protein called sex hormone binding globulin (SHBG). Another blood test can measure the "free" testosterone. However, this type of test is often not very accurate.
Low Testosterone: What You Should Know
As men age, their testosterone levels may drop.
Which physical change could be a sign of low testosterone?
It is normal for older men to lose all interest in sex.
Low testosterone can cause trouble getting an erection.
Which emotional change could be a sign of low testosterone?
A simple blood test can detect low testosterone.
Aging is the only cause of low testosterone.
Low testosterone can make a man's bones weaker.
Testosterone therapy can help:
Testosterone therapy is a good idea for all older men.
In females, the ovaries produce most of the testosterone. The adrenal glands can also produce too much of other androgens that are converted to testosterone. Levels are most often checked to evaluate signs of higher testosterone levels, such as:
Acne, oily skin
Change in voice
Decreased breast size
Excess hair growth (dark, coarse hairs in the area of the moustache, beard, sideburns, chest, buttocks, inner thighs)
Male: 300 to 1,000 nanograms per deciliter (ng/dL) or 10.41 to 34.70 nanomoles per liter (nmol/L)
Female: 15 to 70 ng/dL or 0.52 to 2.43 nmol/L
The examples above are common measurements for results for these tests. Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different specimens. Talk to your provider about the meaning of your specific test results.
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Brent Wisse, MD, board certified in Metabolism/Endocrinology, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.