Testosterone (Free) Direct Test

Testosterone testing is used to diagnose several conditions in both men and women, as well as detecting low levels or deficiencies in men. Testosterone is the main sex hormone in men and is responsible for male physical characteristics. Typically testosterone is considered to be a male sex hormone, but it is present in the blood of females as well. Approximately two-thirds of testosterone circulates in the blood bound to SHBG and less than one-third is bound to albumin. A small percent (less than 4 percent) circulates in the blood as free testosterone.

Testosterone testing is used to evaluate androgen excess or deficiency related to gonadal function, adrenal function, or tumor activity. Testosterone levels may be helpful in men for the diagnosis of hypogonadism, hypopituitarism, Klinefelter syndrome, and impotence (low values). This test is helpful in assessing testicular function in males.

Testosterone levels may be requested in women to investigate the cause of hirsutism, anovulation, amenorrhea, virilization, masculinizing tumors of the ovary, tumors of the adrenal cortices, and congenital adrenal hyperplasia (high values).

Reduced levels of testosterone in men can lead to:

• Infertility
• Decrease in libido/sex drive
• Erectile dysfunction
• Decreased muscle tone
• Moodiness
• Increase in body fat/enlarged breasts

Women should consider testosterone testing if:

• They are concerned about infertility
• Have thinning scalp hair
• Have heavy vaginal bleeding
• Experience low libido
• Have menopausal women
• Irregular or missed periods
• Have unusual bouts of acne or facial/body hair growth

What can this test help diagnose?

Testosterone testing may be used to help evaluate the following conditions:

• Decreased sex drive/libido in men and women
• Erectile dysfunction in men
• Infertility in men and women
• Testicular tumors in men
• Hypothalamus or pituitary gland disorders
• Hirsutism and/or virilization in women