Estradiol Test (E2 test, immunoassay, ECLIA)

The Estradiol (E2) test measures the hormone concentration in your blood using immunoassay techniques such as immunochemiluminescent or radioimmunoassay methods. It is also referred to as the E2 test. Estradiol is a form of estrogen, also known as 17-beta-estradiol. In women, the primary sources of estradiol are the ovaries, while the adrenal glands and adipose tissue contribute to a lesser extent. In men and post-reproductive individuals, estradiol can be synthesized in the adrenal glands and peripheral tissues. During pregnancy, the placenta also produces estradiol.

Features:

• Uses antibodies to bind estradiol.
• Has limited sensitivity and specificity, especially at low estradiol levels (e.g., in men, children, or postmenopausal women, or during HRT).
• May yield false positives due to cross-reactivity with other estrogens.
• Suitable for routine assessment of estradiol in women of reproductive age with higher hormone levels.

Your doctor may order an estradiol test to investigate the causes of:

• Irregular menstrual cycles
• Abnormal vaginal bleeding
• Female infertility
• Menopausal symptoms
• Evaluation of ovarian function or potential decrease in estrogen production, for example, due to low body fat

🔍 What levels of estradiol are considered normal?

• In menstruating women, levels vary depending on the menstrual cycle phase: 15–350 pg/mL
• In postmenopausal women, levels should typically be below 10 pg/mL

Elevated estradiol may indicate early puberty.

🔷 What does a high E2 level mean?

High E2 levels may point to early puberty in girls, ovarian tumors in women, or hormonal imbalances. In men, elevated E2 may be linked to testicular tumors, hormone imbalance, or gynecomastia. In both sexes, it may indicate hyperthyroidism. High estrogen levels may increase the risk of blood clots and stroke.

🔷 What does a low E2 level mean?

A low result may indicate:

• Ovarian insufficiency (early menopause) or estrogen deficiency due to rapid weight loss or anorexia
• Irregular or absent menstrual periods
• Infertility due to anovulation
• Bone weakness and loss of bone mass, as estrogen is essential for bone strength