Testosterone

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Male reproductive anatomy

A testosterone test measures the amount of testosterone in the blood.

Serum testosterone

Blood is drawn from a vein, usually from the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic. An elastic band is placed around the upper arm to apply pressure and cause the vein to swell with blood.

A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. During the procedure, the band is removed to restore circulation. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.

For infants or young children, the area is cleansed with antiseptic and punctured with a sharp needle or a lancet. The blood may be collected in a pipette (small glass tube), on a slide, onto a test strip, or into a small container. A bandage may be applied to the puncture site if there is any bleeding.

The health care provider may advise you to stop taking drugs that may affect the test.

When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.

This test is performed when symptoms indicate there may be abnormal androgen (male hormone) production.

In males, the testes produce the majority of the circulating testosterone. The pituitary hormone LH stimulates the testicular Leydig cells to produce testosterone. In females, the ovaries produce the majority of the testosterone. The adrenal cortex produces another androgen, called DHEAS.

In boys, testosterone levels are used to assess early or late puberty. In men, testosterone levels are critical in the evaluation of impotence and infertility. Testosterone levels are obtained in women to help evaluate excess hair growth, virilization (male body characteristics), and irregular menstrual periods.

Review Date: 03/08/2006
Reviewed By: Robert Hurd, M.D., Department of Biology, COllege of Arts and Sciences, Xavier University, Cincinnati, OH. Review provided by VeriMed Healthcare Network.