Estradiol (E2) Test

An Estradiol (E2) test measures levels of the hormone E2 in the blood. The results can reflect issues ranging from fertility problems to liver damage.

What is an estradiol test for?
Doctors will likely request an estradiol test if they want to find out more about why a person’s sex characteristics are developing in a certain way.

Although estrogen is known as a female sex hormone, it also plays a role in male growth and development.

Estradiol levels can affect how the reproductive system develops. Abnormally high or low levels can influence how the following parts of the body grow and work:

• womb
  
• fallopian tubes
  
• vagina
  
• breasts
  
• libido
  
• erectile function
  
• sperm cells

During their reproductive years, women usually have the highest levels of estradiol. After reaching menopause, estradiol levels are much lower.

Problems caused by abnormal levels of estradiol include:

• menstrual problems
  
• infertility
  
• gynecomastia or a benign swelling of the male breast tissue
  
• ovarian tumors
• breast cancer

An estradiol test can detect early or late puberty. If a child appears to be starting puberty earlier or later than expected, a doctor may order this test.

Transgender women may take estradiol as part of their hormone therapy to develop more female characteristics. If so, their doctor may wish to perform regular estradiol tests to monitor their levels.