Competitive immunoenzymatic colorimetric method for quantitative determination of DHEA-S concentration in saliva. This product is for Research Use Only; International customers contact your representative to receive information about the CE marked version. The DHEA-S (antigen) in the sample competes with the antigenic 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 blue colour that changes into yellow when the Stop Solution (H2SO4) is added. The colour 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.