Free Testosterone is a second- or third-order test for evaluating testosterone status (eg, when abnormalities of sex hormone-binding globulin are present). Testosterone is the major androgenic hormone. It is responsible for the development of the male external genitalia and secondary sexual characteristics. In females, its main role is as an estrogen precursor. In both genders, it also exerts anabolic effects and influences behavior.
For males, this test is recommended to do when the patient may be infertile or are unable to get or maintain an erection; when a boy with either early or delayed sexual maturity (puberty), this test is to be done.
For females, when the patients have male traits, such as a low voice or excessive body hair (hirsutism), abnormal uterine bleeding, do not menstruate (amenorrhea), or are infertile, this test is recommended to be done.
In general, the normal range in males is about 270 to 1070 ng/dL with an average level of 679 ng/dL. A normal male testosterone level peaks at about age 20, and then it slowly declines. Testosterone levels above or below the normal range are considered by many to be out of balance.
