Estradiol Blood Test - More Information

The estradiol test, sometimes known as an estradiol blood test, E2 test or an estrogen lab test, measures the estradiol blood level.

Estradiol (E2) is a steroid hormone that serves important roles in both women and men. E2 is made via several pathways in the body and uses cholesterol, and sometimes estrone, as a precursor. Estradiol is the most common type of estrogen (a larger class of sex hormones) found in the bodies of nonpregnant women and men. As one might expect, the blood level of estradiol will usually vary at different stages of life and, in women, during pregnancy.

In women of childbearing age, estradiol is primarily produced within the follicles of the ovaries. Otherwise, estradiol is also made in smaller quantities in the liver, fat, breast and other tissues. Along with progesterone, estradiol is an important hormone in the growth and maintenance of organs related to sex and fertility such as the uterus, breasts and fallopian tubes which is why it is often ordered with the progesterone test. More specifically, estradiol drives many of the changes in a woman's body during puberty and also impacts bone health, breast development and overall body morphology. Deficiencies can lead to irregular periods, hot flashes, infertility, hair loss, and vaginal dryness.

During a woman's menstrual cycle, estradiol plays various roles supporting the lining of the uterus and germ cells in the ovaries. Additionally, elevations in estradiol blood levels during the cycle lead to an increase in LH blood levels (measurable using the LH test) which ultimately results in ovulation. Estradiol also works synergistically with the hormone progesterone to thicken the endometrial lining in preparation for the implantation of an embryo. During pregnancy, the estriol test is more frequently used as estriol is the most common estrogen found in a pregnant woman. Once out of childbearing years, estradiol continues to be important in regulating fat distribution and bone and joint health. In fact, estrogen deficiencies if post-menopausal women can result in significant bone loss. As such, estradiol testing is helpful in guiding the management of infertility issues.

In men, estradiol, while typically existing at lower levels, still has an important role. Estradiol helps maintain sperm cell health and does have a role in sexual function. Estradiol test levels are also monitored for men who are undergoing testosterone replacement therapy as this form of hormone replacement can cause the estradiol blood test levels to vary out of normal ranges. High estradiol levels, particularly as a consequence of testosterone replacement therapy can result in enlarged breast tissue (gynecomastia) and this estradiol test is sometimes ordered with the testosterone blood test for additional information.

Getting an estradiol test near you at a Quest Diagnostics lab is a relatively simple process as all standard lab locations will have the necessary equipment to perform an estradiol blood test. Once you place your order and select a lab location, you will need to get your blood drawn at the lab. Once your estradiol test results are ready, they will be released to you electronically. Interpreting an estradiol lab test report is not too difficult. As can be seen on the E2 sample report provided above, the estradiol blood level is reported as a number in the results column. The reference range for this blood test is also provided by the lab and, in this particular sample report, the estradiol result of 22 falls within the standard range. In specific contexts, one might expect the estradiol level to be above the reference range and these situations should be interpreted with the help of your medical provider.

This estradiol test uses an immunoassay lab methodology. For people who need a more sensitive estradiol test, please see the estradiol ultrasensitive test which uses the LC/MS/MS lab methodology. This estradiol test is sometimes ordered with the TRT blood test panel and is included in the advanced TRT panel.