Description
INTENDED USE
The Calbiotech, Inc. (CBI) Androstenedione ELISA Kit is intended for the measurement of Androstenedione in serum or plasma.
SUMMARY AND EXPLANATION
Androstenedione is the primary precursor of testosterone in women. It is synthesized in the adrenal gland. Measurement of Androstenedione may be used as an indicator of androgenic activity in women. The steroid hormone Androstenedione is one of the main androgens, besides Testosterone and Dehydroepiandrosterone. In males, androgens are secreted primarily by the Leydig cells of the testes, to some degree also in the adrenal cortex. In females, the androgens are secreted mainly in the adrenal glands and in the ovary. Around 10% of the androgens are derived from peripheral conversion, mainly of DHEA. Androstenedione and Testosterone show high diurnal variability. The highest levels are measured in the morning. At the age of puberty serum androstenedione levels rise, after menopause they decline again. High androstenedione levels are measured during pregnancy. In women, high levels of
androstenedione (47-100% above normal) are generally found in hirsutism, mostly in combination with other androgens as testosterone and DHEA-S. Androstenedione overproduction is due to ovarian dysfunction or maybe of adrenal origin. High circulating androstenedione levels are found in women with polycystic ovaries and 21-hydroxylase effect. Significant lower androstenedione levels are found in postmenopausal osteoporosis.
PRINCIPLE OF THE TEST
The CBI Androstenedione ELISA kit is based on the principle of competitive binding between Androstenedione in the test specimen and Androstenedione-HRP conjugate for a constant amount of rabbit anti-Androstenedione. In the first incubation, goat anti-rabbit IgG-coated wells are incubated with 25μl of Androstenedione standards, patient samples, 50μl Androstenedione-HRP conjugate reagent and 50μl rabbit anti-Androstenedione reagent at room temperature for 60 minutes. During the incubation, HRP labeled Androstenedione competes with the endogenous Androstenedione in the standard and sample, for a fixed number of binding sites of the specific Androstenedione antibody. Thus, the amount of Androstenedione peroxidase conjugate immunologically bound to the well progressively decreases as the concentration of Androstenedione in the specimen increases. Unbound Androstenedione peroxidase conjugate is then removed and the wells washed. Next, a solution of TMB Reagent is added and incubated at room temperature for 15 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 450nm. A standard curve is prepared relating color intensity to the concentration of Androstenedione.
