also known as Testosterone in Serum or Plasma by Immunoassay
Testosterone is a hormone that causes male characteristics. The blood level is used by men to investigate abnormal sexual development and sexual dysfunction. Small amounts are produced in women's ovaries and levels are tested to evaluate virilization. A drop in testosterone levels can contribute to moodiness, weight gain, loss of muscle mass, and diminished libido. Testosterone circulates almost entirely bound to transport proteins: Normally less than 1-2% is free. The principal transport protein for testosterone is known as sex hormone binding globulin (SHBG) or testosterone-estradiol binding globulin (TeBG). Testosterone measurements are used to assess erectile dysfunction, infertility, gynecomastia, and osteoporosis and to assess hormone replacement therapy. This test reports up to a level of Note: This assay should be performed on adult (=18 years) males this Immunoassay does not provide sufficient sensitivity in detecting low concentrations among non-adults and women.