Human chorionic gonadotropin (hCG) is a glycoprotein hormone produced by the placenta. During normal pregnancy the level of this hormone in serum and urine gradually increases up to about the eighth week of pregnancy. hCG has two subunits, namely α and β. The α subunit is similar to the α subunit of the anterior pituitary gland glycoprotein hormones, namely, LH, TSH and FSH. However, the β subunits of these hormones are different. Therefore, this uniqueness distinguishes one hormone from the other, hence specificity. In raising this monoclonal antibody, the immunogen used was βhCG, which helps to make the DBC assay system very specific and sensitive.