Free testosterone is a term that refers to the amount of testosterone in the bloodstream that is not bound to any other chemicals. Free testosterone only accounts for 1-4 percent of the testosterone in a typical males bloodstream. This test is highly valuable for investigating patients with hirsutism, loss of libido and male hypogonadism. HIGH levels may indicate adrenocortical tumor, androgen-secreting ovarian tumor, or pituitary overproduction of ACTH. DECREASED levels are seen in conditions such as hypogonadism, hypopituitarism, estrogen therapy, and some cases of Kleinfelter’s syndrome. See Testosterone, Total, Serum
Early morning sample (7AM - 10AM) is recommended and preferred as testosterone levels vary during the day.