Description

Diagnostic Automation β-HCG ELISA test kit is mainly intended to quantitatively determine Total beta-HCG concentration in human serum.

Human chorionic gonadotropin (HCG) is a sialoglycoprotein with a molecular weight of approximately 46,000 Daltons. HCG is initially secreted by the trophoblastic cells of the placenta shortly after implantation of the fertilized ovum into the uterine wall. The rapid rise in HCG serum levels after conception makes it an excellent marker for early confirmation and monitoring of pregnancy. Physiologically, HCG appears to maintain the corpus luteum, thereby allowing synthesis of progesterone and estrogens that support the endometrium. As uncomplicated pregnancies progress, the placenta assumes the production of these hormones. The serum HCG levels increase to a peak concentration, then decrease and plateau. HCG circulates as the intact molecule in the serum of normal women who have an uncomplicated pregnancy. The subunits are cleared rapidly and excreted by the kidney. The placental hormone, HCG, is similar to luteinizing hormone (LH), follicle stimulating hormone (FSH), and human thyroid stimulating hormone (HTSH). All are glycoprotein consisting of two noncovalently bound dissimilar subunits, designated alpha and beta, with attached carbohydrate sidechains. The alpha subunits of this glycoprotein are very similar. In contrast, the beta subunit portions determine the biological and immunochemical specificities. The beta subunits of HCG and LH exhibit considerable homology in amino acid content. Amino acid residues specific for the beta subunit of HCG confer the immuno-chemical specificity. With the availability of sensitive quantitative assays for the measurement of serum β-HCG, it has been shown that HCG levels can be useful in predicting spontaneous abortions, aiding in the detection of ectopic pregnancy and multiple gestation. Elevated levels of HCG have also been detected in serum from patients with abnormal physiological conditions not related to pregnancy. The HCG EIA test provides a rapid, sensitive and reliable assay. The antibodies developed for the test will determine a minimal concentration of 2 mIU/ml.

The HCG Quantitative ELISA Kit is based on a solid phase enzyme-linked immunosorbent assay. The assay system utilizes one anti-HCG antibody for solid phase (microtiter wells) immobilization and another mouse monoclonal anti-βHCG antibody in the antibody-enzyme (horseradish peroxidase) conjugate solution. The test specimen (serum) is added to the HCG antibody coated microtiterwells and incubated with the Zero Buffer. If antigen is present in the specimen, it will combine with the antibody on the well. The well is then washed to remove any residual test specimen, and HCG antibody labeled with horseradish peroxidase (conjugate) is added. The conjugate will bind immunologically to the β-HCG on the well, resulting in the antigen molecules being sandwiched between the solid phase and enzyme-linked antibodies. After on incubation at room temperature, the wells are washed with water to remove unbound labeled antibodies. A solution of TMB is added and incubated for 20 minutes, resulting in the development of a blue color. The color development is stopped with the addition of 2N HCl, and the color is changed to yellow and measured spectrophotometrically at 450 nm. The concentration of antigen is directly proportional to the color intensity of the test sample.