The DHEA-S (Antigens) in the sample competes with the Antigensic DHEA-S conjugated with horseradish peroxidase (HRP) for binding to the limited number of antibodies anti DHEA-S coated on the microplate (solid phase). After incubation, the bound/free separation is performed by a simple solid-phase washing. Then, the enzyme HRP in the bound-fraction reacts with the Substrate (H2O2) and the TMB Substrate and develops a blu color that changes into yellow when the Stop Solution (H2SO4) is added.The color intensity is inversely proportional to the DHEA-S concentration of in the sample.DHEA-S concentration in the sample is calculated through a calibration curve. Sample Types: saliva. Range: 0.2 - 12 ng/ml. Sensitivity: 0.05 ng/ml. Time: 0.5 hours ? 5-Dehydroepiandrosterone (DHEA-5) is a endogenous natural steroid hormone with 19 carbon atoms. It is the principal steroid hormone produced by the secretion of the adrenal glands, but it is also produced in the gonads and brain. DHEA is the most abundant circulating steroid in human beings. DHEA-S is a natural steroid hormone found primarily in the kidneys and it is derived from the enzymatic conversion of DHEA in the adrenal and extra-adrenal tissues. It is the most abundant hormone in the human body and is a precursor of all sex Steroid. As most DHEA-S is produced by the zona reticularis of the adrenal, it is argued that there is a role in the immune and stress response. DHEA-S may have more biologic roles: for example its production in the brain suggests a role as neurosteroid.