Estriol is a female hormone that exists in blood in the free and conjugated forms (primarily estriol-3-sulfate-16-glucuronide, estriol-16-glucuronide and estriol-3-sulfate). Measurement of the total estriol has been shown to be useful in monitoring the fetal function. During pregnancy, virtually all of the estriol in the maternal circulation is synthesized in the fetoplacental unit. Estriol begins to appear in the maternal circulatory system as a result of synthesis by the feto-placental unit in the ninth week of gestation. During the third trimester, estriol levels in serum and urine normally increase rapidly. Therefore, a low or declining estriol level may be indicative of fetal distress. Although a single estriol measurement may have some value as a serum test, serial determinations to monitor estriol are considered more useful.
Principle of the Assay:
This is an ELISA for the quantitative analysis of Estriol levels in biological fluid. This test kit operates on the basis of competition between the enzyme conjugate and the Estriol in the sample for a limited number of binding sites on the antibody coated plate.
The sample or standard solution is first added to the microplate. Next, the diluted enzyme conjugate is added and the mixture is shaken and incubated at room temperature for one hour. During the incubation, competition for binding sites is taking place. The plate is then washed removing all the unbound material. The bound enzyme conjugate is detected by the addition of substrate, which generates an optimal color after 30 minutes.
Quantitative test results may be obtained by measuring and comparing the absorbance reading of the wells of the samples against the standards with a microplate reader at 650nm. The extent of color development is inversely proportional to the amount of Estriol in the sample or standard. For example, the absence of Estriol in the sample will result in a bright blue color, whereas the presence of Estriol will result in decreased or no color development.
E3560-10A: ELISA Buffer 1x30ml
E3560-10B: Wash Buffer 1x20ml. To be diluted 10x with deionized water. This is used to wash all unbound enzyme conjugate, samples and standards from the plate after the one hour incubation.
E3560-10C: TMB Substrate 1x20ml. Stabilized 3,3', 5,5' Tetramethylbenzidine (TMB) plus hydrogen peroxide (H2O2) in a single bottle. It is used to develop the color in the wells after they have been washed.
E3560-10D: Extraction Buffer, 5x 1x30ml. To be diluted 5x with deionized water. This is used for diluting extracted and non-extracted samples.
E3560-10E: Estriol (HRP) 1x150ul. Estriol HRP concentrate.
E3560-10F: Estriol Standard 1x100ul. Estriol standard at the concentration of 1ug/ml.
E3560-10G: Microtiter Coated Plate 1x96 well Costar(R)microplate with anti-Estriol rabbit antibody precoated on each well. The plate is ready for use as is. Do not wash.
Storage and Stability:
Store all components at 4 degrees C Stable for at least 6 months.