Human Chorionic Gonadotropin (hCG), ß-Subunit, Qualitative

Overview:

Immunoassay for the in vitro quantitative determination of the sum of human chorionic gonadotropin (hCG) plus the hCG beta-subunit in human serum and plasma.1This assay is intended for the early detection of pregnancy.

As with all tests containing monoclonal mouse antibodies, erroneous findings may be obtained from samples taken from patients who have been treated with monoclonal mouse antibodies or who have received them for diagnostic purposes.1 In rare cases, interference due to extremely high titers of antibodies to streptavidin and ruthenium can occur.1 The test contains additives, which minimize these effects.

Similarly to LH, FSH, and TSH, human chorionic gonadotropin (hCG) is a member of the glycoprotein family and consists of two subunits (α- and β-chains) that are associated to the intact hormone.1-7 The α-chains in all four of these glycoprotein hormones are virtually identical, whereas the β-chains have greatly differing structures and are responsible for the respective specific hormonal functions.

hCG is produced in the placenta during pregnancy. In nonpregnant women, it can also be produced by tumors of the trophoblast, germ cell tumors with trophoblastic components, and some nontrophoblastic tumors.

Human chorionic gonadotropin consists of a number of isohormones with differing molecular size. The biological action of hCG serves to maintain the corpus luteum during pregnancy. It also influences steroid production. The serum of pregnant women contains mainly intact hCG.

Measurement of the hCG concentration permits the diagnosis of pregnancy just one week after conception. The determination of hCG in the first trimester of pregnancy is of particular importance. Elevated values here serve as an indication of chorionic carcinoma, hydatiform mole, or multiple pregnancy. Depressed values indicate threatening or missed abortion, ectopic pregnancy, gestosis or intrauterine death.

Elevated hCG concentrations not associated with pregnancy are found in patients with other diseases, such as tumors of the germ cells, ovaries, bladder, pancreas, stomach, lungs, and liver.6,7

1. hCG+ß (Intact human chorionic gonadotropin + the ß-subunit) on Elecsys 1010/2010 and Modular Analytics E170, 2016-08, V 17.0 English [package insert]. Indianapolis, Ind: Roche Diagnostics; 2016.

2. Thomas CM, Reijnders FJ, Segers MF, Doesburg WH, Rolland R. Human Choriogonadotropin (HCG): Comparisons between Determinations of Intact HCG, Free HCG ß-Subunit, and “Total” HCG + ß in Serum during the First Half of High-Risk Pregnancy. Clin Chem. 1990 Apr;36(4):651-655. PubMed 1691055

3. Hoermann R, Berger P, Spoettl G, et al. Immunological Recognition and Clinical Significance of Nicked Human Chorionic Gonadotropin in Testicular Cancer. Clin Chem. 1994 Dec;40(12):2306-2312. PubMed 7527309

4. Schwarz S, Berger P, Wick G. The Antigenic Surface of Human Chorionic Gonadotropin as Mapped by Murine Monoclonal Antibodies. Endocrinology. 1986 Jan;118(1):189-197. PubMed 2416550

5. Runnebaum B, Rabe T. Gynäkologische Endokrinologie, Grundlagen, Physiologie, Pathologie, Prophylaxe, Diagnostik, Therapie. Berlin, Heidelberg, New York, London, Paris, Tokyo: Springer Verlag. 1987;8:43,489-541.

6. Sturgeon CM, McAllister EJ. Analysis of hCG: clinical applications and assay requirements. Ann Clin Biochem. 1998 Jul;35(Pt 4):460-491. PubMed 9681050

7. Marcillac I, Troalen F, Bidart JM, et al. Free Human Chorionic Gonadotropin ß Subunit in Gonadal and Nongonadal Neoplasms. Cancer Res. 1992 Jul 15;52(14):3901-3907. PubMed 1377600