Clinical Significance:
Estrogen Binding Globuln is a Beta-Globulin that binds several steroids in varying degrees. Estradiol binds strongly to Estrogen Binding Globulin but Estrone and Estriol do not. Estrogen Binding Globulin levels are influenced by Estrogens, Thyroid medications, oral contraceptives, and pregnancy, all of which can greatly increase the binding capacity and/or the concentration of Estrogen Binding Globulin. Elevated levels of Estrogen Binding Globulin Index have also been detected in patients with Estradiol Receptor positive breast cancer. In males the Estrogen Binding Globulin Index increases after the age of 50 often leading to decreased androgenization and increased estrogenization.
Reference Range:
Male: 1.0 – 2.0 ug/dl
Female: 1.0 – 3.4 ug/dl
Procedure:
Estrogen Binding Globulin Index is measured by a radiodisplacement assay.
Patient Preparation:
Patient should not be on any Steroid, ACTH, Gonadotropin, Estrogen, or Thyroid medications if possible, for at least 48 hours prior to collection of specimen.
Specimen Collection:
3 ml serum or EDTA plasma should be collected and separated as soon as possible. Minimum specimen size is 1 ml.
Shipping Instructions:
Ship specimens at room temperature or frozen in dry ice.
References:
1. S Pearce, M Dowsett, and SL Jeffcoate. Three Methods Compared for Estimating the Fraction of Testosterone and Estradiol Not Bound to Sex-Hormone-Binding Globulin. Clinical Chemistry 35: 632-635, 1989.
2. BC Nisula, DL Loriaux, and YA Wilson. Solid Phase Method for Measurement of the Binding Capacity of Testosterone-Estradiol Binding Globulin in Human Serum. Steroids 31: 681, 1978.