Estradiol blood test: what it measures and when it is used
An estradiol test measures estradiol, also called E2, in a blood sample. MedlinePlus calls estradiol the main estrogen in nonpregnant females of childbearing age. It is made mostly in the ovaries.
Estradiol
A single test for estradiol, the main form of estrogen measured.
$99
See this test at HealthLabsPrice checked October 2026. Not available in ND, RI, NY, NJ, MD and HI. We earn a commission on sales.
What the test measures
Estradiol is one of the main types of estrogen. According to MedlinePlus, it is mostly made in the ovaries. It helps release an egg each menstrual cycle, thickens the lining of the uterus and helps support brain and bone health.
The same MedlinePlus page names three estrogens that are commonly tested: estrone (E1), estradiol (E2) and estriol (E3). If you want to compare them, see estrogen tests: estradiol vs total estrogen.
Why it is ordered
In females, MedlinePlus says estradiol 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, such as early or late puberty, polycystic ovary syndrome (PCOS), thyroid or pituitary gland disorders and infertility, or certain estrogen-producing tumors of the ovaries. It may also be used to monitor:
- Infertility treatments.
- Hormone therapy for menopause.
MedlinePlus lists abnormal periods or no periods at all among the reasons a woman of childbearing age may need estrogen testing.
The Office on Women’s Health says that if you are in perimenopause, blood hormone tests are not usually needed. A clinician can usually tell from your age, your symptoms and changes in your periods. It adds that if your periods stop before age 40, you can ask about testing. See the perimenopause test and menopause blood test pages for more.
How to prepare
MedlinePlus says you may need to stop certain supplements and medicines, such as the birth control pill and hormone therapy for menopause, before this test. Tell your provider everything you take, and do not stop anything unless your provider tells you to.
The seller’s page for this test describes a simple blood draw, says fasting is not required, and says results appear in your online account within one to three business days. The page does not say whether it is a standard or a sensitive estradiol test. If a clinician’s order names a specific type, make sure the test you buy matches it.
Timing in your cycle
The seller’s page notes that estradiol levels change through the menstrual cycle, but it gives no instruction for which day to book. The right day depends on why you are testing, so follow the lab order, or ask the clinician who requested the test. The cycle timing tool can help you count days.
Reading the result
MedlinePlus says a healthy estrogen level depends on your age, your sex, the reason for the test, the type of estrogen measured and your other test results. It also says labs often use different reference ranges, so compare your number with the range on your own report (How to Understand Your Lab Results). For one published set of limits by cycle phase and after menopause, see estradiol levels.
One estradiol result does not diagnose anything by itself. If your result is flagged, or you have missed periods, symptoms that worry you, or bleeding after menopause, see a clinician. What a low or high result can mean is covered in low estrogen and high estrogen.
Estradiol
$99
See this test at HealthLabsPrice checked October 2026. Not available in ND, RI, NY, NJ, MD and HI. We earn a commission on sales.
Keep reading
- Estradiol levels by cycle phase and after menopause
Published estradiol reference limits for the follicular phase, the luteal phase and after menopause, copied with units, and why your lab's range may differ.
- How to test estrogen levels: estradiol, estrone or total estrogen
Estrogen can be tested in blood, urine or saliva, and there is more than one type. See which test fits your question, how to prepare, and what it can't tell you.
- Low estrogen: what a low estradiol result can mean
A low estradiol result can be expected in some phases of life and a sign of a problem in others. See what it can mean and when to see a clinician.
- High estrogen: what a high estradiol result can mean
A high estradiol result can be normal at some points in the cycle, in pregnancy or with some medicines. See what else it can mean and when to see a clinician.