Estrogens, Fractionated, Serum
- Estrogens, Fractionated, Serum
- Start Date
- Expiration Date
- CPT Codes
- Reference Test
- Transport Info
Centrifuge and immediately transfer serum to separate plastic tube
- Fasting Required?
- Patient Instructions
- Reference Range
Electrochemiluminescent Immunometric Assay (ECLIA)
Estrone (E1) and estradiol (E2) are two major naturally occurring estrogens in pre-menopausal, non-pregnant women. Estradiol is the most biologically active estrogen. Approximately 95% of estradiol is produced in the ovary (follicle, corpus luteum). Estrone is produced primarily from androstenedione originating from either the adrenal cortex or gonads. In premenopausal adult women, more than 50% of estrone is secreted by the ovary. In prepubertal children, men and postmenopausal women, estrone is mainly derived from peripheral tissue conversion of androstenedione. Interconversion of estrone and estradiol also occurs in peripheral tissues. During pregnancy, large amounts of estrone and estradiol are synthesized in the placenta.
Estrone is of little significance in the ovulating women. However, it becomes the predominant estrogen in the absence of functioning follicles in the postmenopausal years. Although the physiologic role of endogenous estrone is not well defined, it is a primary estrogenic component of several pharmaceutical preparations for estrogen replacement therapy. Estrone can serve as an important clinical marker of estrogenicity in postmenopausal women on estrogen replacement therapy.
The former method for quantitating total estrogens used a non-specific RIA method that measured estradiol and estrone, but also measured their metabolites. Consequently, total estrogen values by such a method reflected not just ovarian production of these estrogens, but also hepatic metabolism of the estrogens. The new test will use a specific assay for estrone and a separate specific assay for estradiol. Using this approach, the result will better reflect the status of estrogen production in vivo.