Estradiol E2 is the most potent natural Estrogen, produced mainly by the ovary, placenta, and in smaller amounts by the adrenal cortex, and the male testes. Estradiol is secreted into the blood stream where 98% bound to sex hormone binding globulin (SHBG). Estrogenic activity is effected via estradiol-receptor complexes which trigger the appropriate response at the follicles, uterus, breast, vagina, urethra, hypothalamus, pituitary and to a lesser extent the liver and skin. In non-pregnant women with normal menstrual cycles, estradiol secretion follows a cyclic, biphasic pattern with the highest concentration found immediately prior to ovulation. During pregnancy, maternal serum Estradiol levels increase considerably, to well above the pre-ovulatory peak levels and high levels are sustained throughout pregnancy. Serum Estradiol measurements from an Estradiol assay are a valuable index in evaluating a variety of menstrual dysfunctions such as precocious or delayed puberty in girls and primary and secondary amenorrhea and menopause. Estradiol levels have been reported to be increased in patients with feminizing syndromes, gynaecomastia and testicular tumors. In cases of infertility, serum Estradiol measurements are useful for monitoring induction of ovulation following treatment.

Catalog number SDL7961
Product type ELISA
Quantity 96 Tests (12×8 breakable strip wells)
Standard range 10-1000 pg/ml
Analytical Sensitivity 10 pg/ml
Sample volume 25 µl/well
Species Human

The SDi Estradiol (E2) Enzyme Immunoassay is an Estradiol Blood Test intended for the quantitative determination of Estradiol (E2) concentration in human serum or plasma.

The SDi E2 EIA (Estradiol Blood Test) is based on the principle of competitive binding between E2 in the test specimen and E2-HRP conjugate for a constant amount of rabbit anti-Estradiol. In the incubation, goat anti-rabbit IgG-coated wells are incubated with E2 standards, controls, patient samples, Estradiol-HRP Conjugate Reagent and rabbit anti-Estradiol reagent at room temperature for 90 minutes. During the incubation, a fixed amount of HRP-labeled E2 competes with the endogenous E2 in the standard, sample, or quality control serum for a fixed number of binding sites of the specific E2 antibody. E2 peroxidase conjugate immunologically bound to the well progressively decreases as the concentration of E2 in the specimen increases. Unbound E2 peroxidase conjugate is then removed and the wells washed. Next, a solution of TMB Reagent is added and incubated at room temperature for 20 minutes, resulting in the development of blue color. The color development is stopped with the addition of stop solution, and the absorbance is measured spectrophotometrically at 450 nm. A standard curve is obtained by plotting the concentration of the standard versus the absorbance garnered with the Estradiol Blood Test.

Storage and Stability
Product should be stored at 2-8 °C. Product is stable for 24 months from the date of manufacturing.

For research use only. Not for use in diagnostic procedures.

1. Tsang, B.K., Armstrong, D.T. and Whitfield, J.F., Steroid biosynthesis by isolated human ovarian follicular cells in vitro, J. Clin. Endocrinol. Metab., 1980; 51: 1407-1411.
2. Gore-Langton, R.E. and Armstrong, D.T., Follicular steroidogenesis and its control. In: Knobil, E., and Neill, J. et al., ed. The Physiology of Reproduction. Raven Press, New York; 1988: 331-385.
3. Hall, P.F., Testicular steroid synthesis: Organization and regulation. In: Knobil, E., and Neill, J. et al., ed. The Physiology of Reproduction. Raven Press, New York; 1988: 975-998.
4. Siiteri, P.K., Murai, J.T., Hammond, G.L., Nisker, J.A., Raymoure, W.J. and Kuhn, R.W., The serum transport of steroid hormones, Rec. Prog. Horm. Res., 1982; 38: 457-510.
5. Baird, D.T., Ovarian steroid secretion and metabolism in women. In: James, V.H.T., Serio, M. and Giusti, G., eds. The Endocrine Function of the Human Ovary. Academic Press, New York; 1976: 125-133.
6. McNatty, K.P., Baird, D.T., Bolton, A., Chambers, P., Corker, C.S. and McLean, H., Concentration of oestrogens and androgens in human ovarian venous plasma and follicular fluid throughout the menstrual cycle, J. Endocrinol., 1976; 71: 77-85.
7. Abraham, G.E., Odell, W.D., Swerdloff, R.S., and Hopper, K., Simultaneous radioimmunoassay of plasma FSH, LH, progesterone, 17-hydroxyprogesterone and estradiol-17β during the menstrual cycle, J. Clin. Endocrinol. Metab., 1972; 34: 312-318.
8. March, C.M., Goebelsmann, U., Nakumara, R.M., and Mishell, D.R. Jr., Roles of estradiol and progesterone in eliciting the midcycle luteinizing hormone and follicle-stimulating hormone surges. J. Clin. Endocrinol. Metab., 1979; 49: 507-513.
9. Simpson, E.R., and MacDonald, P.C., Endocrinology of pregnancy. In: Williams, R.H., ed., Textbook of Endocrinology. Saunders Company, Philadelphia; 1981: 412-422.
10. Jenner, M.R., Kelch, R.P., Kaplan, S.L. and Grumbach, M.M., Hormonal changes in puberty: IV. Plasma estradiol, LH, and FSH in prepubertal children, pubertal females and in precocious puberty, premature thelarche, hypogonadism and in a child with feminizing ovarian tumor. J. Clin. Endocrinol. Metab., 197 2; 34: 521-530.
11. Goldstein, D., Zuckerman, H., Harpaz, S., et al., Correlation between estradiol and progesterone in cycles with luteal phase deficiency. Fertil. Steril., 1982; 37: 348-354.
12. Kirschner, M.A., The role of hormones in the etiology of human breast cancer. Cancer, 1977; 39: 2716-2726.
13. Odell, W.D. and Swerdloff, R.S., Abnormalities of gonadal function in men. Clin. Endocr., 1978; 8: 149-180.
14. MacDonald, P.C., Madden, J.D., Brenner, P.F., Wilson, J.D. and Siiteri, P.K., Origin of estrogen in normal men and in women with testicular feminization, J.Clin. Endocrinol. Metabl., 1979; 49: 905-916.
15. Fishel, S.B., Edwards, R.G., Purdy, J.M., Steptoe, P.C., Webster, J., Walters, E., Cohen, J., Fehilly, C. Hewitt, J., and Rowland, G., Implantation, abortion and birth after in vitro fertilization using the natural menstrual cycle or follicular stimulation with clomiphene citrate and human menopausal gonadotropin, J. In Vitro Fertil. Embryo Transfer, 1985; 2: 123-131.
16. Ratcliffe, W.A., Carter, G.D., Dowsett, M., et al., Oestradiol assays: applications and guidelines for the provision of a clinical biochemistry service, Ann. Clin. Biochem., 1988; 25:466-483.
17. Tietz, N.W. ed., Clinical Guide to Laboratory Tests, 3rd Edition, W.B. Saunders, Co., Philadelphia, 1995: 216-217.
18. USA Center for Disease Control/National Institute of Health Manual, “Biosafety in Microbiological and Biomedical Laboratories”, 1984.
19. ICN Guide to Endocrine Testing. Diagnostic Division, ICN Biomedicals, Inc. pp. 2:15-19.