An estradiol test measures the amount of a hormone called estradiol in the blood. Estradiol is the most important form of estrogen found in the body. Most of it is made in and secreted from the ovaries, adrenal cortex, and placenta.

Estradiol is responsible for the growth of the female uterus, Fallopian tubes, and vagina. It promotes breast development and the growth of the outer genitals. The hormone plays a role in the distrubtion of body fat in women and stops the process of growing taller.

Blood is drawn from a vein, usually from the inside of the elbow or the back of the hand. The site is cleaned with germ-killing medicine (antiseptic). The health care provider wraps an elastic band around the upper arm to apply pressure to the area and make the vein swell with blood.

Next, the health care provider gently inserts a needle into the vein. The blood collects into an airtight vial or tube attached to the needle. The elastic band is removed from your arm.

Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.

In infants or young children, a sharp tool called a lancet may be used to puncture the skin and make it bleed. The blood collects into a small glass tube called a pipette, or onto a slide or test strip. A bandage may be placed over the area if there is any bleeding.

Consult your health care provider about the need to stop taking drugs that can affect test results, including:

• Estrogen therapy
• Birth control pills

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 used to check the function of the ovaries, placenta, or adrenal glands, particularly when certain types of ovarian tumor are suspected, or when there is delayed or abnormal development of male or female body characteristics.

Women undergoing assisted reproductive technology (ART) for infertility may have this test at regular intervals in combination with ultrasound imaging to monitor their ovaries' response to stimulation.

• Male: 10 to 60 picograms per milliliter (pg/mL)
• Female (premenopausal): 20 to 400 pg/mL
• Female (postmenopausal): 5 to 25 pg/mL

Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

Greater-than-normal levels may indicate ovarian tumor.

Lower-than-normal levels may indicate Turner syndrome.

The test may also be used to monitor patients with hypopituitarism and women undergoing certain fertility treatments.

Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.

Other risks associated with having blood drawn are slight but may include:

• Excessive bleeding
• Fainting or feeling light-headed
• Hematoma (blood accumulating under the skin)
• Infection (a slight risk any time the skin is broken)