A testosterone blood test measures the levels of testosterone, a hormone primarily produced in the testicles in males and ovaries in females, in the blood. Testosterone plays an important role in the development of male physical characteristics, as well as in the maintenance of bone health, muscle mass, and libido in both males and females.

The test is usually ordered for males who are experiencing symptoms of low testosterone, such as decreased sex drive, fatigue, or erectile dysfunction, or for females who are experiencing symptoms of high testosterone, such as excess body hair or irregular menstrual periods.

Low testosterone levels in males, known as hypogonadism, can be caused by a variety of factors, including aging, certain medications, or certain medical conditions such as obesity or diabetes. Treatment for hypogonadism may involve testosterone replacement therapy, lifestyle changes, or medication adjustments.

High testosterone levels in females, known as hyperandrogenism, can be caused by conditions such as polycystic ovary syndrome (PCOS) or certain medications. Treatment for hyperandrogenism may involve medication to regulate hormone levels, lifestyle changes, or other interventions depending on the underlying cause.