Competitive immunoenzymatic colorimetric method for the quantitative measurement of Androstenedione concentration in saliva. This product is for Research Use Only; International customers contact your representative to receive information about the CE marked version. Androstenedione (antigen) in the sample competes with the antigenic Androstenedione conjugated with horseradish peroxidase (HRP) for binding onto the limited number of antibodies anti- androstenedione 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 color that changes into yellow when the Stop Solution (H2SO4) is added. The colour intensity is inversely proportional to the Androstenedione concentration of in the sample. Androstenedione concentration in the sample is calculated through a standard curve.