A critical shortage in the antibody used in our Estradiol ELISA Kit (Item No. 582251) prompted the need for a replacement Estradiol ELISA Kit (Item No. 501890) Our scientists developed a new antiserum with less cross reactivity compared to the previous kit and changed the sample preparation/extraction protocol to a simpler and less hazardous format that provides improved specificity. Synthetic 17β-estradiol and samples of human plasma were tested side by side in both kits to compare performance.

Sensitivity

The new kit offers sensitivity values comparable to those of the previous kit. However, the concentrations of analyte or assay values of the new kit are detectable over a wider assay range compared to the previous kit.

Previous Estradiol Kit (Item No. 582251)	New Estradiol Kit (Item No. 501890)

Sample Preparation/Extraction Protocol

Plasma and serum samples may require extraction prior to quantification in the assay to eliminate potential substances like bulk proteins or lipids that may interfere with steroid quantification. Extraction can also help concentrate the sample to within the measurement range of the assay. We updated the extraction protocol in the new kit. This new protocol requires a single precipitation step with methanol, instead of the repeated liquid/liquid extraction steps needed with methylene chloride, which carries greater hazardous materials precautions.

Cross Reactivity

The new kit demonstrates improved specificity for estradiol with minimal detection of estradiol 3-glucuronide, estrone, estradiol 3-sulfate, and estradiol 17-glucuronide.

For additional information on the performance of this kit, including spike and recovery and linearity data please refer to the kit booklet (PDF).

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Steroid Hormone Assay Frequently Asked Questions