Equine Estrone-3-Sulfate ELISA Kit (E3S)

Full Name: Equine Estrone-3-Sulfate ELISA Kit (E3S)
Reactivity: Equine
Sample Type: Serum
Sensitivity: 0.14 ng/ml


Estrone-3-Sulfate (also known as E3S) is found to be synthesised in the cotyledonary or the fetal portion of the placentome and it is the main conjugated form of estrogen during pregnancy. There are many hormones which are vital for the various complex events that are occurring during pregnancy in all animals. In mare, these can include: formation of endometrial cups, development of secondary corpora lutea and the maintenance of the corpus luteum function. Estrone-3-sulfate is the main precursor for estradiol and progesterone. It functions as a progestogen, ovulatory agent and gonadotropin secretion inhibitor in mammals including humans.

PMSG, free estrogens and progesterone have also be associated with these processes. The measurement is designed to offer a non-invasive diagnosis process in order to monitor the levels of feto-placental unit during pregnancy. Where it is only in mares that the normal fetal development displays rapid elevation values between 75- 100 days of gestation.


Equine estrone-3-sulfate ELISA kit is intended for detecting quantitative levels of estrone-3-sulfate (E3S) using mares serum samples. This assay has a minimum sensitivity detection limit of 0.14 ng/ml.


All reagents supplied need to be stored at 2 °C – 8 °C, unopened reagents will retain reactivity until expiration date. Do not use reagents beyond this date.

  • Divisible Microplate: Coated with a polyclonal anti-equine E3S antibody.
  • Calibrators (0-7): Concentrations of 0, 5, 10, 50, 100, 300 and 1000 ng/ml, respectively.
  • Biotin-Labelled Antibody.
  • Enzyme-Labelled Streptavidine.
  • Equine E3S Sample Buffer.
  • TMB-Substrate Solution.
  • Stop Solution.
  • Wash Buffer (10x Concentrated).


The minimum sensitivity detection limit of mare estrone-3-sulfate (E3S) using current equine estrone-3-sulfate ELISA kit was approximately 0.14 ng/ml. The dynamic range for this assay is 5.0 – 1,000.0 ng/ml.


– Sensitivity: 0.14 ng/ml.
– Specificity: Highly specific for estrone-3-sulfate, with low cross-reactivities to other steroids.
– Intra-Assay: 6.2 – 7.8%
– Inter-Assay: 5.3 – 9.6%
– Recovery: 88 – 107%
– Linerarity: 85 – 96%


  1. Increases in serum estrone sulfate level are associated with increased mammographic density during menopausal hormone therapy. Cancer Epidemiol Biomarkers Prev. (2008) 17 (7): 1674-81. Crandall C.J., et al.
  2. Estrone sulfate concentrations as an indicator of fetal demise in horses. Am J Vet Res. (1988) 49 (2): 184-7. Kasman L.H., et al.
  3. Pharmacokinetics and pharmacodynamics of conjugated equine estrogens: chemistry and metabolism. Proc Soc Exp Biol Med. (1998) 217 (1): 6-16. Review. Bhavnani BR.
  4. The isolation of estrone sulfate and estradiol-17 beta sulfate from stallion testes. Can J Biochem. (1969) 47 (8): 811-5. Raeside J.I.


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