Clinical comparison of immunoradiometric assays for intact versus beta-specific human chorionic gonadotropin.
Monoclonal immunoradiometric assays (IRMA) for human chorionic gonadotropin (hCG) are available for either intact hCG (IhCG) or beta subunit hCG (beta hCG). The authors evaluated the clinical applications of both methods. Serum samples (N = 180) were divided into the following five clinical groups: Group 1: elevated luteinizing hormone (LH), follicular stimulating hormone (FSH), and thyroid-stimulating hormone (TSH), which share alpha subunits with hCG; Group 2: pregnancy; Group 3: trophoblastic tumors; Group 4: malignancy; and Group 5: positive rheumatoid factor or anti-nuclear antibody (ANA). The values of beta hCG versus IhCG for Group 1 showed statistical significance but no clinical significance, indicating negligible cross-reactivity in the alpha subunit group. beta hCG values, although exceeding the IhCG values, correlated well (r = 0.97) in intrauterine pregnancies; however, these values were not believed to be clinically significant. There is negligible interference by alpha subunits, elevated rheumatoid factor, ANA, or malignancy in the determination of IhCG versus beta hCG. The authors conclude that either the IhCG or beta hCG assays may be used in clinical conditions in which a potential exists for interference of alpha subunits, autoantibodies, or heterophile antibodies or in malignancy.
Department of Pathology, University of Arkansas for Medical Sciences, Little Rock 72205.
M G
MG
Pardue
E H
EH
Taylor
S
S
London
R C
RC
Walls
A A
AA
Pappas
D000974:Antibodies, Antinuclear / Q000032:analysis; D000911:Antibodies, Monoclonal; D006063:Chorionic Gonadotropin / Q000097:blood*; D018997:Chorionic Gonadotropin, beta Subunit, Human; D005069:Evaluation Studies as Topic; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D006801:Humans; D006828:Hydatidiform Mole / Q000097:blood*; D015592:Immunoradiometric Assay / Q000379:methods; D007986:Luteinizing Hormone / Q000097:blood; D010446:Peptide Fragments / Q000097:blood*; D011247:Pregnancy; D011271:Pregnancy, Ectopic / Q000097:blood*; D012044:Regression Analysis; D012217:Rheumatoid Factor / Q000032:analysis; D013972:Thyrotropin / Q000097:blood; D014594:Uterine Neoplasms / Q000097:blood*
D000974:Antibodies, Antinuclear; D000911:Antibodies, Monoclonal; D006063:Chorionic Gonadotropin; D018997:Chorionic Gonadotropin, beta Subunit, Human; D010446:Peptide Fragments; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D013972:Thyrotropin; D012217:Rheumatoid Factor