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 mIUml between the 8th and 12th weeks of gestation and decline to 20,000 mIUml 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 neoplsia. 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 sensitivity of this ELISA test is 0.5mIUml.