Definition of Estradiol test:

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 released from the ovaries, adrenal cortex, and the placenta, which forms during pregnancy to feed a developing baby.

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 distribution of body fat in women and stops the process of growing taller.

How the test is performed:

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.

How to prepare for the test:

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

• Estrogen therapy
• Birth control pills

How the test will feel:

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.

Why the test is performed:

This test is used to check the function of the ovaries, placenta, or adrenal glands. Your doctor may order this test if certain types of ovarian tumors are suspected, when there is delayed or abnormal development of male or female body characteristics, or the menstrual cycle is absent. A woman's level of estradiol can vary widely, depending on where she is in her menstrual cycle.

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.