Testosterone Serum – Free and Bound
Testosterone is a hormone produced by the testes in response to luteinizing hormone (LH). LH is secreted by pituitary glands when testosterone level is low. Thus, pituitary gland stimulates the production of testosterone in the testicles of males.
Testosterone is also produced by ovaries in females and by adrenal glands, in small amounts. Testosteroneperforms several functions in a male body. In men, Testosterone levels increase during puberty – as a result, the secondary sexual characteristics like the development of facial hair, muscles, sperms, body hair and deeper voice develop. Testosterone helps in the development of muscle mass, bones, and ensures proper sexual function. Majority of the testosterone is bound to sex hormone binding protein (SHBG) and a small amount of it circulates freely in the blood. Both the bound and free levels of testosterone are measured in the blood.
Why is the test ordered?
A testosterone test may be prescribed to help evaluate decreased sex drive, infertility, erectile dysfunction, early or delayed puberty in boys, and testicular tumours in men. The test may also be ordered to evaluate virilisation and hirsutism in girls and women.
When is the test ordered?
The test may be ordered if a man has low libido, erectile dysfunction or is suspected of being infertile, is presented with decreased muscle mass, lack of beard or body hair andgynecomastia. The test may also be prescribed if a boy seems to undergo either early or delayed puberty – based on signs and symptoms. In women, the test may be recommended ifthey have masculine features, irregular menses, amenorrhea and if they are unable to get pregnant.
How is the sample collected?
A blood sample is drawn from a vein in the arm.
How to prepare for the test?
No special preparation is required for the test.