An estradiol test is a blood test that measures the amount of estradiol in your blood. It’s also called an E2 test.
Estradiol is a form of the hormone estrogen, and it’s also called “17 beta-estradiol.” The ovaries, breasts, and adrenal glands make estradiol. During pregnancy, the placenta also makes estradiol.
Estradiol helps with the growth and development of female sex organs, including the:
- fallopian tubes
Estradiol helps to control the way fat is distributed in the female body. It’s also essential for bone and joint health in females.
Males also have estradiol in their bodies. Their levels of estradiol are lower than the levels in females. In males, the adrenal glands and testes make estradiol. Estradiol has been shown in vitro to prevent destruction of sperm cells, but its clinical importance in sexual function and development in men is likely less significant than in women.
Your doctor may order an estradiol test if female or male sex characteristics aren’t developing at the normal rate. An estradiol level that’s higher than normal indicates that puberty is happening earlier than usual. This is a condition known as precocious puberty.
Lower levels of estradiol may indicate late puberty. The test can help your doctor find out if there are problems with your adrenal glands. It can also help determine if treatment for hypopituitarism (decreased function of the pituitary gland) is working.
A doctor may order estradiol testing to look for causes of:
- abnormal menstrual periods
- abnormal vaginal bleeding
- infertility in women
Your doctor may also order an estradiol test if your menstrual cycle has stopped and you’re having symptoms of menopause. During and after menopause, a woman’s body will gradually produce less estrogen and estradiol, contributing to the symptoms experienced during menopause. A test of your estradiol level can help your doctor determine if you are preparing to enter menopause or you are already going through the transition.
The estradiol test can indicate how well the ovaries are working. Therefore, your doctor may also order this test if you have symptoms of an ovarian tumor. The symptoms include:
- bloating or swelling in your abdomen
- trouble eating due to feeling full after eating a small amount of food
- pain in your lower abdominal and pelvic area
- weight loss
- frequent urination
If you’re pregnant or you’re on infertility treatments, your doctor may order an estradiol test to help keep track of your progress.
An estradiol test usually isn’t used alone to make a diagnosis. However, the results of this test may help your doctor decide if further testing is necessary.
The risks associated with having an estradiol test are low. The risks include:
- multiple punctures due to trouble finding a vein
- excessive bleeding
- feeling lightheaded
- hematoma, which is an accumulation of blood under your skin
- infection at the needle puncture site
Certain factors can affect estradiol levels. It’s important that you and your doctor discuss these factors. They may ask you to stop taking a certain medication or change the dose before your test.
Medications that can affect your estradiol levels include:
- birth control pills
- estrogen therapy
- phenothiazines, which are used to treat schizophrenia and other mental disorders
- tetracycline, which is an antibiotic
- ampicillin, which is an antibiotic
Estradiol levels can also vary throughout the day and with a woman’s menstrual cycle. As a result, your doctor may ask you to have your blood tested at a certain time of day or at a certain time in your cycle. Conditions that can affect estradiol levels include:
- high blood pressure
- kidney disease
- reduced liver function
An estradiol test is a blood test. This may also be called a blood draw or “venipuncture.” A technician called a phlebotomist will perform the blood test.
Blood is usually drawn from a vein on the inside of your elbow or the back of your hand. To begin, the technician will use antiseptic to clean the skin. This helps prevent infection. They will then wrap an elastic band called a tourniquet around your upper arm. This causes the vein to swell with blood. The technician will then insert a needle into your vein and draw blood into a tube.
The technician will draw enough blood for the number of tests ordered by your doctor. The blood draw will only take a couple of minutes. The process may be slightly painful. Most people report a pricking or burning sensation.
After drawing the blood, the technician will apply pressure to stop the bleeding. They’ll apply a bandage to the puncture site and send your blood sample to laboratory for testing.
Estradiol levels that are higher than normal may suggest:
- early puberty
- tumors in the ovaries or testes
- gynecomastia, which is the development of breasts in men
- hyperthyroidism, which is caused by an overactive thyroid gland
- cirrhosis, which is scarring of the liver
Lower than normal levels of estradiol may suggest:
- Turner syndrome, which is a genetic disorder in which a female has one X chromosome instead of two
- ovarian failure (premature menopause), which occurs when the ovaries stop functioning before the age of 40
- polycystic ovarian syndrome (PCOS), which is a hormone disorder with a wide range of symptoms that’s also believe to be a leading cause of infertility in women
- depleted estrogen production, which can be caused by low body fat
- hypogonadism, which occurs when the ovaries or testes don’t produce enough hormone
Once the results of your estradiol level test are available, your doctor will discuss the results in detail with you and then present you with options for treatment.