Human Chorionic Gonadotropin (hCG) ELISA
The Calbiotech, Inc. (CBI) hCG ELISA Kit is intended for the quantitative measurement of hCG in human serum or plasma.
Human Chorionic Gonadotropin (hCG) is a 40 kD glycoprotein hormone secreted by the placenta. hCG has two subunits, alpha and beta. The alpha subunit is similar to the alpha subunit found in LH, FSH and TSH glycoprotein hormones. However, the beta subunit is specific and differs from hormone to hormone.
The serum hCG rises in early pregnancy to concentrations of 50,000-150,000 mIU/ml between the 8th and 12th weeks of gestation and decline to 20,000 mIU/ml by the 18th week where they remain for the duration of the pregnancy. The increased level of hCG in non-pregnant women or men suggest neoplasia. Thus hCG measurement is useful for the recognition and monitoring of chorionic tumors and as a tumor marker for other malignancies that produce hCG ectopically. These include testicular, pancreatic, and bronchogenic pulmonary cancers.
The CBI hCG ELISA is an adapted solid phase sandwich ELISA method. The samples, biotin labeled anti-hCG and anti-hCG-HRP conjugate are added to the wells coated with Streptavidin. hCG in the patient’s serum binds to binds to the anti-hCG antibodies and forms a sandwich on the streptavidin coated plate. Unbound protein and HRP conjugate are washed off by wash buffer. Upon the addition of the substrate, the intensity of color is proportional to the concentration of hCG in the samples. A standard curve is prepared relating color intensity to the concentration of hCG in the sample.