Synonyms: N/A

Why It Is Done

This test is done to determine if the level of testosterone in a persons body is abnormal. In a male it can determine whether a problem with the testicles or pituitary gland is preventing a man from being able to father a child (infertility). Evaluate a man's sexual problems. Determine whether increased testosterone production is causing a boy younger than age 10 to have early (precocious) puberty. Determine the response to testosterone-lowering medications in men with advanced prostate cancer. Evaluate the cause of osteoporosis in a man.

For a female it is used to evaluate why a woman is developing male features, such as excessive facial and body hair (hirsutism) and a deep voice. Evaluate irregular menstrual periods in women.

Test Overview

A testosterone test measures the level of this male hormone (androgen) in the blood. Testosterone affects sexual features and development. In men, it is produced in large amounts by the testicles. In both men and women, testosterone is also produced in small amounts by the adrenal glands; and, in women, by the ovaries.

The release of testosterone is controlled by a hormone called luteinizing hormone, or LH, which is produced by the pituitary gland Most of the testosterone in the blood is attached to a protein called sex hormone binding globulin (SHBG). A small amount is attached to albumin.

How To Prepare

No special preparation is necessary.