Testosterone (Total)

Though often considered a male sex hormone, testosterone is present in females in smaller amounts. In both sexes, testosterone helps control your sex drive and helps with muscle and bone growth. In men, testosterone testing can help your provider check on testicular function, while in women it can help look into causes of unwanted hair growth or other signs of higher-than-expected male hormones.

All the testosterone in your blood is either bound to proteins or unbound (free). Free testosterone is the biologically active form that's more available for your body to use when building bones and muscles. However, most of your testosterone is bound to proteins such as sex-hormone-binding globulin (SHBG) and albumin. The bond with SHBG is tight, while the bond with albumin is looser. When testosterone is bound, your body can't use it as easily. This is necessary for your health. Having most of your testosterone bound to proteins makes sure your body doesn't use too much.

A free testosterone result can be especially helpful when total testosterone is borderline or when conditions that change SHBG levels could mask the true amount of usable testosterone.

A testosterone level test alone can't diagnose any health conditions, but abnormal results with symptoms may be a sign of a health problem.

In men, low total testosterone with high LH and FSH (other pituitary hormones) usually points to a problem with the testicles themselves (primary hypogonadism). Low testosterone with low or normal LH and FSH points to a problem with the pituitary gland or hypothalamus in the brain (secondary hypogonadism). Very high levels in men can suggest a tumor of the testicle or adrenal gland, or use of testosterone or related drugs.

In women, higher than normal testosterone can be a sign of polycystic ovary syndrome (PCOS), congenital adrenal hyperplasia, or, much less often, a tumor of the ovary or adrenal gland. Total testosterone above about 200 ng/dL in a woman is usually a clue to look for a tumor.

Your test results may mean different things depending on which test was done, your age, your symptoms, the results of other tests, and other conditions you may have. If your results are not normal, it doesn't always mean you have a medical condition that needs treatment. It's normal for testosterone levels to decrease with age. If you have questions about your results, talk to your provider.