MaxLight(TM) 550 is a new Yellow-Green photostable dye conjugate comparable to Alexa Fluor(TM)546, 555, DyLight(TM)549 , Cy3(TM), TRITC and offers better labeling efficiency, brighter imaging and increased immunodetection. Absorbance (550nm), Emission (575nm), Extinction Coefficient 150,000. Human Chorionic Gonadotropin (HCG) is a glycoprotein, which is secreted in large quantities by normal trophoblasts. It is present only in trace amounts in non-pregnant urine and sera but rises sharply during pregnancy. HCG is composed of two non-identical, non-covalently linked polypeptide chains designated as the a-and b-subunits. The a-subunit of HCG is nearly identical to that of thyroid stimulating hormone (TSH), follicle stimulating hormone (FSH), and luteinizing hormone (LH). A germ cell tumor which is positive for cytokeratin, placental alkaline phosphatase (PLAP), and HCG but negative for EMA and AFP is probably a choriocarcinoma. Note: Applications are based on unconjugated antibody.