What is an estrogen test?

An estrogen test measures the level of estrogens in a sample of your blood, urine (pee), or saliva (spit).

Estrogens are a group of hormones that play a key role in female reproductive health, including puberty, menstruation, pregnancy, and menopause. However, estrogens are also important for more general bodily functions in both males and females, including:

• Healthy cholesterol and blood sugar levels.
• Bone and muscle strength.
• Brain functions such as the ability to focus.

There are many types of estrogen, but only three types are commonly tested:

• Estrone, also called E1, is the weakest of the three types and is made mostly by body fat and the adrenal glands (glands that sit on top of each kidney) in males and females. In females, the ovaries (the glands that contain eggs) also make estrone. Estrone is the only type of estrogen that females continue to make after menopause.
• Estradiol, also called E2, is the main estrogen in nonpregnant females of childbearing age. It's mostly made in the ovaries and makes pregnancy possible by helping to release an egg each menstrual cycle and by thickening the lining of the uterus (the place where a fetus grows). It also helps support brain and bone health. Males make small amounts of this estrogen in the testicles (the glands that make sperm).
• Estriol, also called E3, is an estrogen that increases during pregnancy. It's made in the placenta (the organ that grows in the uterus to provide nutrients and oxygen to the fetus). It helps your body prepare for breastfeeding and the birthing process. Males and nonpregnant females have very low levels of this estrogen.

Though estrogen levels depend on many factors, including sex and age, levels that stay too high or too low may be a sign of a health problem.

Other names: estradiol test, estrone (E1), estradiol (E2), estriol (E3), estrogenic hormone test

What is it used for?

In females, estradiol and/or estrone testing may be used to help diagnose conditions that may cause or be caused by estrogen levels that are too high or too low. These include:

• Early or late puberty.
• Polycystic ovary syndrome (PCOS), a condition that affects your ovaries.
• Thyroid or pituitary gland disorders such as hypothyroidism.
• Infertility (problems getting pregnant).
• Certain estrogen-producing tumors of the ovaries.
• Perimenopause, the period leading up to menopause.

Estradiol and/or estrone testing may also be used to help monitor:

• Infertility treatments.
• Hormone replacement therapy for menopause.
• Hormone treatment for certain cancers, such as breast cancer.

During pregnancy, an estriol hormone test may be used to:

• Help diagnose certain birth defects.
• Monitor a high-risk pregnancy.

In males, estradiol and/or estrone tests may be used to see whether too much estrogen is causing conditions, such as:

• Late puberty.
• Breast growth (gynecomastia).
• Infertility.
• Erectile dysfunction (ED), a condition in which you have problems having and/or keeping an erection.
• Testicular or adrenal cancer.

Why do I need an estrogen test?

If you are female, you may need estrogen testing if you:

• Have signs of early or delayed puberty such as the development of breasts, body hair, and widened hips before the age of 8 or after the age of 13.
• Are of childbearing age and have abnormal periods or no periods at all.
• Are unable to get pregnant after a year of trying.
• Have a high-risk pregnancy.
• Have symptoms of menopause, including hot flashes and/or night sweats.
• Use hormone replacement therapy after menopause.
• Have vaginal bleeding after menopause.

If you're pregnant, you may have an estriol test between weeks 15 and 20 of your pregnancy. The test may be part of a group of prenatal tests called a triple screen test or a quad screening test, which are used to  check whether your fetus has a high risk for a genetic birth defect such as Down syndrome. You may be more likely to have a baby with a birth defect if you:

• Have a family history of birth defects.
• Are age 35 or older.
• Have diabetes.
• Have had a viral infection during pregnancy.

If you are male, you may need estrogen testing if you have:

• Signs of late puberty, such as delayed development of muscle mass and growth of testicles and penis.
• Enlarged breasts or other symptoms of too much estrogen.

What happens during an estrogen test?

If you are tested at your provider's office or a lab, you will provide a blood or urine sample. If you use an at-home test, the sample is usually saliva (spit).

For a blood test: A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.

For a urine test: You'll need to collect all your urine during a 24-hour period. This is called a 24-hour urine sample test. You will be given a special container to collect your urine and instructions on how to collect and store your samples. Your provider will tell you what time to start. The test generally includes the following steps:

• To begin, urinate in the toilet as usual. Do not collect this urine. Write down the time you urinated.
• For the next 24 hours, collect all your urine in the container.
• During the collection period, store the urine container in a refrigerator or in a cooler with ice.
• 24 hours after starting the test, try to urinate if you can. This is the last urine collection for the test.
• Return the container with your urine to your provider's office or the laboratory as instructed.

For an at-home saliva test: You'll collect a sample of saliva and send it to a lab for testing. Ask your provider which saliva test is best to use. Be sure to follow all the instructions that come with your kit and discuss your results with your provider.

Will I need to do anything to prepare for the test?

You may need to stop taking certain supplements and medicines, such as the birth control pill and hormone replacement therapy, before this test. Tell your provider about everything you take, but don't stop taking any medicines unless your provider tells you to.

Are there any risks to the test?

There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.

There is no known risk to a urine or saliva test.

What do the results mean?

A healthy level of estrogen depends on several factors, including:

• Your age.
• Your sex.
• The reasons for having the test.
• The type of estrogen that was measured.
• The results of other tests you may have had.

Estrogen levels in males, for example, don't change much throughout life. Therefore, a high level is usually a sign of a health condition such as infertility or an estrogen-producing tumor.

In females, however, estrogen levels change a lot. They rise during puberty, are at their highest during pregnancy, and decline after menopause. Because estrogen levels change so often, you may need to be tested more than once to look for a trend in your estrogen levels over time. Talk with your provider to find out what your results mean for your health.

Learn more about laboratory tests, reference ranges, and understanding results.