The E2 – Estradiol test measures the level of estradiol, a primary form of estrogen, in the blood. Estradiol plays a key role in the development and regulation of the female reproductive system, menstrual cycle, and secondary sexual characteristics. It also supports bone health, cardiovascular function, and reproductive tissues. This test helps evaluate menstrual irregularities, infertility, symptoms of menopause, and monitor hormone therapy. In men, it assists in assessing conditions like gynecomastia or fertility issues. Abnormal estradiol levels may indicate ovarian, adrenal, or testicular disorders. Physicians often order this test to guide diagnosis, track treatment progress, and assess hormonal balance for both women and men.
Also Known As : E2 Test, Estradiol Blood Test, 17-beta Estradiol Test, Estrogen (E2) Test, Serum Estradiol Test
- Report In : Within 12 Hours
- Sample Type : Blood
- Fasting : Not Required
The E2 test measures the level of the hormone estradiol in the blood.
Estradiol is one of the main forms of estrogen, especially in people who are biologically female and in their reproductive years.
In females, it’s primarily produced by the ovaries (and also adrenal glands, fat, placenta during pregnancy). In males, smaller amounts are made by the testes and adrenal glands.
It is used to assess reproductive/hormonal health: menstrual function, fertility, puberty timing, ovarian/adrenal/testicular function, menopause transition, tumor-screening in some cases.
- Estradiol (E2) — measured in pg/mL or pmol/L
It is a simple blood test: a sample of your blood is drawn from a vein, usually in the arm.
In most cases there is no special diet or fasting required (though follow your lab/doctor’s instructions).
Important: Tell your doctor about all medications, supplements, hormone treatments etc. Because some can affect estradiol levels. For example: birth-control pills, estrogen therapy, testosterone, DHEA supplements, certain antibiotics.
If this test is being done in a fertility or menstrual-cycle context, timing within your cycle might matter (e.g., Day 3 of cycle etc) for interpretation.
To evaluate menstrual or fertility issues: e.g., irregular periods, amenorrhea, infertility in women.
To assess ovarian function or reserve: For instance, in fertility work-ups the estradiol on day 3 helps evaluate how the ovary is responding.
To check for puberty timing abnormalities: In adolescents with signs of early or delayed puberty.
To monitor menopause/hormone-replacement therapy: Because estradiol levels drop after menopause, monitoring may help.
To help detect tumors or other endocrine issues: For example, ovarian, adrenal or testicular tumors producing estrogen may elevate E2.
In men, if there are signs of feminisation, gynecomastia, low libido or hormone disruption, this test might help.
Does this test require fasting?
Usually no special fasting necessary, but follow your doctor/lab’s instructions. Some labs allow “normal” eating.
Can medications affect the result?
Yes. Hormonal drugs (estrogen, birth control), supplements (DHEA), steroids, and other endocrine medications may influence estradiol levels. Always inform your doctor about medications.
I’m male – do I need this test?
Possibly – though estradiol is much lower in males, testing may be ordered if there are symptoms of hormonal imbalance (e.g., gynecomastia, infertility, low libido).
My result is “high” – should I panic?
Not immediately. “High” must be interpreted in context (cycle phase, pregnancy, medication use, lab method). Your doctor will look at your clinical picture and possibly order further tests.
When is the ideal time to measure this during a menstrual cycle?
For fertility/ovarian reserve assessment, often Day 3 of the cycle is used (along with FSH & AMH). However, the timing depends on the clinical question.