Clinical Significance:
Estradiol is one of the three main Estrogens derived from metabolism of Testosterone and also converted reversibly to Estrone. Estradiol is produced by ovarian follicles. Estradiol is the most biologically potent of the Estrogens. Estradiol is excreted into the urine in several different conjugated forms and also as unconjugated Estradiol. Estradiol is bound strongly to Estrogen Binding Globulin but is also present in the “free” (unbound) form or loosely bound to Albumin. Estradiol exhibits a biphasic secretion with levels higher in the luteal phase. Estradiol peaks at ovulation and is frequently used as an indicator of ovulation. Estradiol levels decrease dramatically after menopause with the major source of Estradiol being peripheral conversion from Testosterone.
Reference Ranges:
Male: 0.8 – 3.5 ng/dl
Female:
Follicular: 3.0 – 11.0 ng/dl
Luteal: 7.0 – 30.0 ng/dl
Menopausal: Up to 1.3 ng/dl
Procedure:
Estradiol is measured by EIA/ELISA following extraction of specimens.
Patient Preparation:
Patient should not be on any Steroid, ACTH, Gonadotropin or Estrogen medications, if possible, for at least 48 hours prior to collection of specimen. Oral contraceptives and estrogen replacement therapy may influence Estradiol levels.
Specimen Collection:
3 ml serum or EDTA plasma should be collected and separated as soon as possible. Minimum specimen size is 0.5 ml.
Special Specimens:
For tumor/tissue and various fluids (i.e. CSF, peritoneal, synovial, etc.) contact the Institute for requirements and special handling.
Shipping Instructions:
Ship specimens at room temperature or frozen in dry ice.
References:
1. CJ Munro, GH Stabenfeldt, JR Cragun, LA Addiego, JW Overstreet and BL Lasley. Relationship of Serum Estradiol and Progesterone Concentrations to the Excretion Profiles of Their Major Urinary Metabolites as Measured by Enzyme Immunoassay and EIA/ELISA. Clinical Chemistry 37: 838-844, 1991.
2. MJ Reed, RW Cheng, CT Noel, HAF Dudley, and VHT James. Plasma Levels of Estrone, Estrone Sulfate, and Estradiol and the Percentage of Unbound Estradiol in Postmenopausal Women with and without Breast Disease. Cancer Research 43: 3940-3943, 1983.