Testosterone, Free (Direct) With Total Testosterone Blood Test
Free and Total Testosterone Blood Test (Labcorp)
This test measures both Free and Total Testosterone levels in the blood. Testosterone is the primary male sex hormone. However, it is present in both men and women. In men, testosterone is produced primarily in the testicles. Small amounts of testosterone are produced by the ovaries in women and the adrenal glands in both sexes. Testosterone stimulates the development of secondary sex characteristics during puberty in men. In adult men, testosterone regulates sex drive and helps maintain muscle mass. Luteinizing Hormone (LH), which is produced by the Pituitary Gland, controls how much testosterone is produced. Measuring testosterone can help to diagnose the cause for a number of conditions in men such as delayed or early puberty, erectile dysfunction, and testicular tumors. It can also help evaluate conditions which affect both men and women such as decreased sex drive, infertility and pituitary disorders.
The majority of testosterone is bound to the proteins Sex Hormone-Binding Globulin and Albumin. The portion of testosterone which is not bound is known as Free Testosterone. Free Testosterone is available for the body to use. Measuring both free and total testosterone can give a more complete picture of a person's testosterone levels, especially if they have a condition which causes abnormal levels of hormone binding proteins.
Testosterone testing is commonly ordered for men who are experiencing erectile dysfunction, loss of muscle mass, fertility issues or decreased sex drive. It may also be ordered for boys who are showing signs of delayed or early puberty. A testosterone test may be ordered for women who are having irregular menstrual periods, difficulty becoming pregnant or are experiencing symptoms such as hair loss, low voice and excessive facial or body hair. A Sex Hormone Binding Globulin Blood Test is commonly ordered along with Testosterone.
Please note that the Free Testosterone test has no established reference interval for people age 0-19. Results for people in this age group will not include a range of which values are considered normal.
Turnaround time for the Testosterone test is typically 3-5 business days.
Where can I find a Testosterone, Free and Total test near me?
Check our lab finder to locate a collection site in your area.
Note: Result turn around times are an estimate and are not guaranteed. Our reference lab may need additional time due to weather, holidays, confirmation/repeat testing, or equipment maintenance.
It is recommended that someone taking Biotin (also known as vitamin B7 or B8, vitamin H, or coenzyme R) stop consumption at least 72 hours prior to the collection of a sample.