Human chorionic gonadotropin (HCG) is a glycoprotein secreted by trophoblast cells of the placenta, which is composed of alpha and beta dimer glycoproteins.The glycoprotein hormone with a molecular weight of 36700, the α subunit is basically similar to the FSH (follicle stimulating hormone), LH (luteinizing hormone) and TSH (thyroid stimulating hormone) secreted by the pituitary gland, so they can cross react with each other, while the β subunit has different structures.Mature women form embryos after the fertilized eggs move to the uterine cavity for implantation. During the development and growth of fetus, placental syncytiotrophoblast cells produce a large amount of HCG, which can be excreted into urine through the blood circulation of pregnant women.When the pregnancy is 1 to 2.5 weeks, the level of HCG in serum and urine can rise rapidly, reaching the peak in the eighth week of pregnancy, and then dropping to the middle level in the fourth month of pregnancy, and maintaining until the third trimester of pregnancy.At present, the commonly used detection methods are: latex aggregation inhibition test and hemagglutination inhibition test;Radioimmunoassay (RIA);Enzyme linked immunosorbent assay (ELISA);Monoclonal antibody colloidal gold test.
The examination of HCG is of great significance to the diagnosis of early pregnancy, and has certain value in the diagnosis, differentiation and course observation of pregnancy related diseases, trophoblastic tumors and other diseases.
1. The increase is seen in: early pregnancy, hydatidiform mole, malignant mole, choriocarcinoma, seminoma, teratoma, ectopic HCG secreting tumors (such as gastric cancer, pancreatic cancer, lung cancer, colon cancer, liver cancer, ovarian cancer, digestive system cancer, etc.).
