Research Areas



  • Assay Type Competitive ELISA
  • Sample Type Serum, Plasma, Urine, Fecal Extracts, Tissue Culture Media
  • Sensitivity 26.4 pg/mL
  • Species Estrone-3-sulfate (E1S) is identical across species
  • Assay Duration 2.5 Hours
  • Samples/Plate 40 in Duplicate
  • Readout Colorimetric, 450 nm
  • Standard Curve The Estrone-3-Sulfate (E1S) ELISA Kit
  • Description

    Assay Principle: 

    The Estrone-3-Sulfate (E1S) ELISA Kit quantitatively measures E1S in serum, plasma, fecal extracts, urine, and tissue culture media. The Estrone-3-Sulfate (E1S) ELISA Kit is a competitive ELISA with a run time of 2.5 hours. Please read the complete kit insert for more information before performing this assay.

    Use our provided E1S standard to generate a standard curve for the assay. Pipette the standards or diluted samples into a transparent microtiter plate coated with our goat anti-rabbit IgG antibody. Add the E1S peroxidase conjugate and the E1S polyclonal rabbit antibody. Then incubate the mixture covered at room temperature, shaking for 2 hours. The immunological reaction occurs between the anti-E1S antibody, the E1S antigen in the sample or standard, and the E1S-peroxidase conjugate. As the E1S concentration in the sample increases, the bound E1S-peroxidase conjugate decreases, causing a decrease in signal and vice versa. 

    After the 2-hour incubation, wash away the excess E1S-peroxidase conjugate and add the TMB substrate. The TMB substrate reacts with the bound E1S-peroxidase conjugate generating a signal detected by a plate reader at 450nm. Use the intensity and the standard curve to calculate the E1S concentration in the samples.


    Estrone-3-sulfate (E1S) is synthesized in the fetal or cotyledonary portion of the placentae. Estrone sulfate, present in plasma at a higher concentration than either unconjugated estrone or estradiol in nonpregnant women and normal men, appears to originate almost entirely from a conjugation of estrone and converted estradiol in non-glandular tissues. Estrone sulfate is quantitatively the most important circulating estrogen. Breast tumors contain sulfatase activity and can convert estrone sulfate into estradiol. Cryptorchidism, where one or both testicles fail to descend, is a prevalent defect in horses. Bilaterally cryptorchid stallions do not produce viable spermatozoa but often exhibit typical secondary sexual characteristics. Several investigators have suggested measuring testosterone and estrone sulfate serum levels as reliable diagnostic aids for the condition.