Testosterone Levels Test Test

A testosterone levels test measures the amount of the hormone testosterone in your blood. Testosterone helps control sex drive, muscle and bone growth, and other functions in both males and females.

What this test measures

This test measures the amount of testosterone in a blood sample. Testosterone is a hormone that controls sex drive, muscle and bone growth, and other body functions. Most testosterone in the blood is bound to proteins, but free testosterone is more available for the body to use.

What your results mean

Reference ranges vary by laboratory and by your age and sex. MedlinePlus does not publish a single normal range for this test — always read your result against the range printed on your own lab report and discuss it with your provider.

Higher-than-normal results

In males, high testosterone levels may be caused by a tumor in the testicles, steroid use, or an adrenal gland disorder such as congenital adrenal hyperplasia (CAH). In females, high levels may be caused by polycystic ovary syndrome (PCOS), ovarian cancer, other ovary problems, an adrenal gland disorder, or a pituitary gland disorder.

Lower-than-normal results

In males, low testosterone levels may be caused by problems with the testicles, chronic diseases (like liver or kidney disease), a pituitary gland disorder, benign tumors, injury to the testicles, alcohol use disorder, or genetic diseases such as Klinefelter syndrome. In females, low levels are normal, but extremely low levels may be a sign of an adrenal gland disorder, a pituitary gland disorder, or a disorder of the ovaries.

Frequently asked questions

What does a testosterone levels test measure?

It measures the amount of the hormone testosterone in a sample of your blood.

What is the difference between total, free, and bioavailable testosterone tests?

A total testosterone test measures both bound and free testosterone. A free testosterone test measures only the unattached form. A bioavailable testosterone test measures free testosterone and testosterone attached to proteins other than SHBG.

Can a testosterone test alone diagnose a health condition?

No, a testosterone level test alone can't diagnose any health conditions, but abnormal results with symptoms may be a sign of a health problem.

What can cause high testosterone levels in females?

High testosterone levels in females may be caused by polycystic ovary syndrome (PCOS), ovarian cancer, other ovary problems, an adrenal gland disorder, or a pituitary gland disorder.

Do testosterone levels change with age?

Yes, it's normal for testosterone levels to decrease with age.

Sources

MedlinePlus: Testosterone Levels Test — NIH MedlinePlus

Last updated July 7, 2026. Information is aggregated from official public sources and is not a substitute for professional medical care.