Estradiol is a hormone, specifically a type of oestrogen, made in a woman's ovaries. Doctors often order the test to determine how well the ovaries are functioning for women suffering from infertility or having menopause symptoms.
The estradiol test typically occurs on day three of a woman's menstrual cycle (with day one being the first day of the menstrual period) by evaluating blood taken from the patient's arm.
Normal level results for the estradiol test are not clearly defined, according to the Advanced Fertility Center of Chicago. They like to see levels lower than 80 picograms per millilitre.
Levels higher than the normal range can indicate poor ovarian reserve (the supply of a women's remaining eggs) or poor ovulation.
Abnormal estradiol levels can indicate that a woman would have reduced response to ovulation-induction medications (such as clomiphene) and decreased chances of successful in-vitro fertilisation.
The test for normal levels of estradiol is often done in conjunction with follicle-stimulating hormone test, according to the Advanced Fertility Center of Chicago. Follicle-stimulating hormone is the hormone that produces mature follicles (or eggs).