Related Experiment Video
Updated: Aug 21, 2026
Purification of HLA-G+ Extravillous Trophoblasts from Human Term Placental Tissues for Phenotyping and Functional Analysis
Published on: March 13, 2026
Establishment, value assignment, and characterization of new WHO reference reagents for six molecular forms of human
Adrian Bristow1, Peter Berger, Jean-Michel Bidart
1National Institute for Biological Standards and Control, Potters Bar, Herts, UK.
Background:
The International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) established a Working Group to investigate means of improving the comparability of immunoassays for human chorionic gonadotropin (hCG), which was selected as a prototype glycoprotein analyte. The Working Group identified development of unambiguous nomenclature and production of new highly purified International Reference Reagents calibrated in substance concentrations as its primary objectives.
Methods:
Preparations of intact hCG, nicked hCG, hCG beta-subunit, nicked hCG beta-subunit, hCG alpha-subunit, and hCG beta-core fragment were purified from a crude urinary hCG preparation, ampouled, lyophilized, and assigned values in substance concentrations (mol/L). Value assignment and accelerated degradation studies were carried out in accordance with WHO protocols for International Reference Reagents.
Results:
The ampouled standards were assigned final values based on the recovery of immunoreactive material after reconstitution. The degradation studies showed that the standards were highly stable.
Conclusions:
The nomenclature of hCG-related molecules and immunoassays has been adopted by the IFCC, and the standards prepared and characterized by the Working Group have been formally adopted by the WHO as the First International Reference Reagents for six hCG-related molecules. These developments will enable better understanding of what assays for hCG measure and should ultimately help to improve the clinical application of these assays.
