Test Overview

An estrogen test measures the level of the most important estrogen hormones (estradiol, estriol, and estrone) in a blood or urine sample.

• Estradiol is the most commonly measured type of estrogen for nonpregnant women. The amount of estradiol in a woman's blood varies throughout her menstrual cycle . After menopause , estradiol production drops to a very low but constant level.
• Estriol levels usually are only measured during pregnancy. Estriol is produced in large amounts by the placenta , the tissue that links the fetus to the mother. It can be detected as early as the 9th week of pregnancy, and its levels increase until delivery. Estriol can also be measured in urine.
• Estrone may be measured in women who have gone through menopause to determine their estrogen levels. It also may be measured in men or women who might have cancer of the ovaries , testicles , or adrenal glands .

Both men and women produce estrogen hormones. Estrogens are responsible for female sexual development and function, such as breast development and the menstrual cycle. In women, estrogens are produced mainly in the ovaries and in the placenta during pregnancy. Small amounts are also produced by the adrenal glands. In men, small amounts of estrogens are produced by the adrenal glands and testicles. Small amounts of estrone are made throughout the body in most tissues, especially fat and muscle. This is the major source of estrogen in women who have gone through menopause.

Why It Is Done

A test for estrogen is done to:

• Help detect fetal birth defects (especially Down syndrome ) during pregnancy. When the test for estriol is combined with alpha-fetoprotein (AFP) and human chorionic gonadotropin (hCG), it is called a triple screen test. When the amount of a hormone called inhibin A is also measured along with estriol, AFP, and hCG, the test is called a quad marker screen. Other blood tests and fetal ultrasound may be done as well.
• Evaluate estrogen-producing tumors of the ovaries in girls before menstruation starts and in women after menopause.
• Explain abnormal sexual characteristics in men, such as enlarged breasts (gynecomastia). This test can also help detect the presence of estrogen-producing tumors growing in the testicles.
• Monitor therapy with fertility medicines.

How To Prepare

No special preparation is required before having an estrogen test.

Tell your health professional if you:

• Are menstruating. Note where you are in your menstrual cycle.
• Are using birth control pills, patches, or rings and other forms of hormonal birth control.
• Are or might be pregnant.

Talk to your health professional about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results will indicate. To help you understand the importance of this test, fill out the medical test information form (What is a PDF document?) .

How It Is Done

The health professional drawing blood will:

• Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.
• Clean the needle site with alcohol.
• Put the needle into the vein. More than one needle stick may be needed.
• Attach a tube to the needle to fill it with blood.
• Remove the band from your arm when enough blood is collected.
• Apply a gauze pad or cotton ball over the needle site as the needle is removed.
• Apply pressure to the site and then a bandage.

How It Feels

You may feel nothing at all from the needle puncture, or you may feel a brief sting or pinch as the needle goes through the skin. Some people feel a stinging pain while the needle is in the vein. However, many people do not feel any pain or have only minor discomfort once the needle is positioned in the vein.

Risks

There is very little risk of complications from having blood drawn from a vein.

• You may develop a small bruise at the puncture site. You can reduce the risk of bruising by keeping pressure on the site for several minutes after the needle is withdrawn.
• In rare cases, the vein may become inflamed after the blood sample is taken. This condition is called phlebitis and is usually treated with a warm compress applied several times daily.
• Continued bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medicines can also make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medicine, tell your health professional before your blood is drawn.

Results

An estrogen test measures the level of the most important estrogen hormones (estradiol, estriol, and estrone) in a blood or urine sample.

Results are usually available within 24 hours.

Normal

For girls and women between puberty and menopause, estrogen levels vary throughout the menstrual cycle . Normal values may vary widely from lab to lab.

Many conditions can change estrogen levels. Your health professional will discuss any significant abnormal results with you in relation to your symptoms and medical history.

High values

High values may be caused by:

• Ovarian stimulation used to treat infertility (for example, before in vitro fertilization ).
• Cancer, such as cancer of the ovaries , testicles , or adrenal glands .
• Serious liver disease ( cirrhosis ).
• A pregnancy with more than one fetus, such as twins or triplets.
• Early (precocious) puberty.

Low values

Low values may be caused by:

• Problems with ovarian function, which can be caused by a failure of an ovary to develop properly ( Turner's syndrome ) or because of a drop in pituitary gland activity.
• Anorexia nervosa .
• Menopause.
• A problem with the fetus or placenta during pregnancy.

What Affects the Test

Reasons you may not be able to have the test or why the results may not be helpful include:

• Hormone replacement therapy after menopause.
• Birth control pills, patches, or rings and other forms of hormonal birth control.
• Having a test that uses a radioactive substance, such as a bone scan , within 1 week before the test.
• Medicines, such as clomiphene (Serophene, Clomid) or steroids (for example, prednisone).
• High levels of sugar in the urine caused by diabetes .

What To Think About

• Blood estrogen levels are a more accurate indicator of how well the ovaries are working than urinary estrogen levels.
• Tests that measure blood levels of progesterone, luteinizing hormone, and follicle-stimulating hormone are often used to study the problems that can affect fertility and the menstrual cycle. For more information, see the medical tests Progesterone, Luteinizing Hormone, and Follicle-Stimulating Hormone.
• The level of estriol in the blood is often used in a maternal serum triple or quadruple screening test. Usually done between 15 and 20 weeks, these tests check the levels of three or four substances in a pregnant woman's blood. The triple screen measures alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG), and unconjugated estriol (uE3). The quad screen measures these three substances plus the hormone inhibin A. The levels of these substances—along with a woman's age and other factors—help the doctor estimate the chance that the baby may have certain problems or birth defects. For more information, see the medical tests Alpha-Fetoprotein (AFP) in the Blood, Human Chorionic Gonadotropin (hCG), and Hormone Inhibin A.
• In some cases a combination of screening tests is done in the first trimester to look for Down syndrome . The first trimester screening often combines ultrasound measurement of the thickness of the fetus's neck (nuchal translucency) and measurements of hCG and a protein called pregnancy-associated plasma protein A to check for problems. For more information, see Birth Defects Testing.

References

Other Works Consulted

• Fischbach FT, Dunning MB III, eds. (2004). Manual of Laboratory and Diagnostic Tests, 7th ed. Philadelphia: Lippincott Williams and Wilkins.
• Handbook of Diagnostic Tests (2003). 3rd ed. Philadelphia: Lippincott Williams and Wilkins.
• Pagana KD, Pagana TJ (2002). Mosby’s Manual of Diagnostic and Laboratory Tests, 2nd ed. St. Louis: Mosby.

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