The estradiol blood test measures the levels of estradiol, a form of estrogen hormone, in the bloodstream. Estradiol is primarily produced by the ovaries in females and plays a crucial role in various reproductive functions and overall hormonal balance. The estradiol blood test is commonly used to assess the functioning of the ovaries and monitor hormonal health, often ordered as part of fertility evaluations, menstrual irregularity assessments, and menopause management.