Over 30 estrogens have been identified, but only three are measured for use in clinical practice: estradiol, estriol, and estrone. Estradiol is the most biologically active, naturally occurring estrogen. Both estriol and estrone are metabolites of estradiol. Additionally, estriol forms as the result of conversion of testosterone and estrone. Estrone forms from the conversion of androstenedione, which is synthesized by the adrenal gland.
In premenopausal women, estradiol is the most abundant form of estrogen, whereas in postmenopausal women, estrone is the most abundant. The shift from estradiol to estrone is due to atrophy of the ovaries, which results in the majority of estrogen being produced from the conversion of androstenedione.
A decrease in estradiol levels to less than 20 pg/mL causes loss of its beneficial effects, resulting in decreased calcium resorption, accelerated bone loss and an increase in triglyceride levels and cholesterol/HDL ratio.
Reference range is:
Population |
Reference Range |
Children |
<10 pg/mL |
Males |
10-50 pg/mL |
Females premenopausal |
35-525 pg/mL |
Females postmenopausal |
0-35 pg/mL |
Specimen requirement is one red top or SST tube of blood.
|
