Estrogens, Fractionated, LC/MS

Estrone (E1) is one of the three major endogenous estrogens. It is produced primarily in peripheral tissues and is often measured in estrogen fractionation panels to characterize hormonal status.

For males: Estradiol (E2) is the main active estrogen in men, mostly made by conversion from testosterone. It supports bone and sexual function, but high levels can contribute to gynecomastia, fluid retention, and lower libido. Interpret alongside testosterone and SHBG.

For females: Estradiol (E2) is the main active estrogen in women and is produced mainly by the ovaries. It regulates the menstrual cycle and ovulation, and supports bone and reproductive health. Levels change a lot across the cycle, so interpretation depends on cycle day and hormone use.

Estriol (E3) is an estrogen measured in fractionated estrogen testing, most commonly to provide additional context alongside estradiol and estrone. Estriol levels rise substantially in pregnancy, so interpretation uses trimester-specific reference ranges when pregnancy phase is available.