Human Chorionic Gonadotropin—A Review of the Literature

Importance The measurement of human chorionic gonadotropin (hCG) levels in different body fluids is a commonly utilized tool in obstetrics and gynecology, as well as other fields. It is often one of the first steps in the medical workup of female patients, and the results and interpretation of this test can have significant downstream ramifications. It is essential to understand the uses and limitations of hCG as a testing and therapeutic measure to appropriately evaluate, counsel, and treat patients. Objective The purpose of this article is to review the current literature on hCG, including its origins, structure, pharmacokinetics, metabolism, and utility in testing and medical treatment. Evidence Acquisition Original research articles, review articles, and guidelines on hCG use were reviewed. Conclusions and Relevance While the primary function of hCG is to maintain early pregnancy, testing for hCG demonstrates that this molecule is implicated in a multitude of different processes where results of testing may lead to incorrect conclusions regarding pregnancy status. This could affect patients in a myriad of settings and have profound emotional and financial consequences. In addition, hCG testing may be revealing of alternative pathology, such as malignancy. It is imperative to understand the nuances of the physiology of hCG and testing methods to effectively use and interpret this test for appropriate patient management. Target Audience Obstetricians and gynecologists, family physicians Learning Objectives After participating in this activity, the provider should be better able to describe the origins, molecular structure, and effects of hCG and its isoforms; explain the mechanism, strengths, and limitations of different hCG testing modalities as well as potential causes of false-positive and false-negative tests; and evaluate the recommendations for, as well as the implications and limitations of, hCG testing in clinical research, the perioperative setting, and other common clinical scenarios.