Free beta-hCG ELISA kit can be used for the quantitative determination of free beta subunit of human chorionic gonadotropin (free β-hCG) concentration in human serum. This Free beta-hCG ELISA kit test is not intended for the use in Down syndrome screening procedures. The minimal detectable concentration of ß-hCG in this free β-hCG ELISA kit is estimated to be 0.25 ng/ml. No hook effect was observed in this free β-hCG ELISA kit.
The free β-hCG ELISA kit is based on the principle of a solid phase enzyme-linked immunosorbent assay. The free β-hCG ELISA kit assay system utilizes a unique monoclonal antibody directed against a distinct antigenic determinant on the β-subunit of the hCG molecule. Mouse monoclonal anti-β-hCG antibody is used for solid phase immobilization on the microtiter wells of this free β-hCG ELISA kit. A rabbit anti-β-hCG antibody is in the antibody-enzyme (horseradish peroxidase) conjugate solution. The test sample is allowed to react sequentially with the two antibodies, resulting in the β-hCG molecules being sandwiched between the solid phase and enzyme-linked antibodies. After incubation two separate 30 minute incubations at 37 °C, the wells are washed with water to remove unbound labeled antibodies. A solution of TMB Reagent is added and incubated for 20 minutes, resulting in the development of a blue color. The color development is stopped with the addition of Stop Solution changing the color to yellow. The concentration of β-hCG is directly proportional to the color intensity of the test sample. Absorbance is measured spectrophotometrically at 450 nm.
Unopened free β-hCG ELISA kit should be stored at 2-8°C upon receipt and the microtiter plate should be kept in a sealed bag with desiccants to minimize exposure to damp air. Opened test of the free β-hCG ELISA kit will remain stable until the expiration date shown, provided it is stored as described above. All reagents should be brought to room temperature (18-25°C) before use. Standards:Reconstitute each lyophilized standard with 1.0 ml distilled water. Allow the reconstituted material to stand for at least 20 minutes and mix gently. Reconstituted standards will be stable for up to 30 days when stored sealed at 2-8°C.
Human Chorionic Gonadotropin (hCG) is a glycoprotein hormone normally produced by placenta during pregnancy. The hormone is present in blood and urine around seven to thirteen days following implantation of the fertilized ovum. Structurally intact hCG molecules consist of two non-covalently linked polypeptide subunits, the alpha and beta chain subunits. Measurement of intact hCG and of the alpha subunit of hCG appears to give similar results in blood and urine but not the levels of beta subunit.
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