title: Free beta-chorionic gonadotropin: a cross-reactivity study of two immunometric assays used in prenatal maternal serum screening for Down's syndrome.
abstract: We have evaluated the cross-reactivity characteristics of two distinct immunometric assays for the measurement of free beta-human chorionic gonadotropin (free beta). These maternal serum assays have been used in the initial studies which evaluated free beta as a marker in the prenatal detection of Down's syndrome. It has been suggested that free beta assays are subject to substantial potential for cross-reactivity. To confirm that free beta was the analyte responsible for enhanced detection efficiency both non-competitive and competitive cross-reactivity evaluations were undertaken. These studies demonstrated acceptably small cross-reactivity to other glycoprotein hormones or their beta components. We conclude that properly designed free beta assays will provide specific analyte measurement and improved detection efficiency in Down's syndrome screening.
authors.affiliation: Research Division, NTD Laboratories Inc., New York 11514.
authors.forename: J N
authors.initials: JN
authors.lastname: Macri
authors.forename: K
authors.initials: K
authors.lastname: Spencer
authors.forename: R W
authors.initials: RW
authors.lastname: Anderson
authors.forename: E J
authors.initials: EJ
authors.lastname: Cook
mesh_terms: D000911:Antibodies, Monoclonal; D015415:Biomarkers / Q000097:blood; D006063:Chorionic Gonadotropin / Q000097:blood* / Q000276:immunology; D018997:Chorionic Gonadotropin, beta Subunit, Human; D003429:Cross Reactions; D004314:Down Syndrome / Q000175:diagnosis*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008970:Molecular Weight; D010446:Peptide Fragments / Q000097:blood* / Q000276:immunology; D011247:Pregnancy; D011296:Prenatal Diagnosis
chemical_list: D000911:Antibodies, Monoclonal; D015415:Biomarkers; D006063:Chorionic Gonadotropin; D018997:Chorionic Gonadotropin, beta Subunit, Human; D010446:Peptide Fragments