DHEA-S ELISA
The Calbiotech Inc. (CBI); DHEA-S ELISA kit is used for the quantitative measurement of DHEA-S in human serum and plasma.
DHEA-S is a more specific product of the adrenals and measurements of this steroid are widely intended in clinical practice. The clinical importance of plasma assays of DHEA-S is associated with the diagnosis of adrenal hyperplasia and differential diagnosis of hirsutism.
The CBI DHEA-S kit is based on the principle of competitive binding between DHAEA-S in the test specimen and HRP conjugated DHEA-S for a constant amount of anti-DHEA-S antibody. In the first incubation, Goat-anti-Rabbit-IgG coated wells are incubated with 10μl of DHEA-S standards, patient samples, 50μl DHEA-S Enzyme (HRP) reagent and 50μl anti-DHEA-S Antibody reagent, at room temperature, for 60 minutes. During the incubation, HRP labeled DHEA-S competes with the endogenous DHEA-S in the standard and sample, for a fixed number of binding sites of the DHEA-S antibody, while simultaneously the Anti DHEA-S antibody binds to the immobilized secondary antibody. Thus, the amount of DHEA-S HRP conjugate immunologically bound to the well progressively decreases as the concentration of DHEA-S in the specimen increases. Unbound DHEA-S HRP conjugate is then removed and the wells washed. Next, TMB Reagent is added and incubated at room temperature for 30 minutes, resulting in the development of blue color. The color development is stopped with the addition of stop solution, and the absorbance is spectrophotometrically measured at 450nm. A standard curve is prepared relating color intensity to the concentration of DHEA-S.
- Tietz, N. W., Textbook of Clinical Chemistry, Saunders, 1968