Detection of Antinuclear Antibodies by Solid-Phase Immunoassays and Immunofluorescence Analysis

• Published in: Clinical chemistry (Baltimore, Md.) Md.), 2004-11, Vol.50 (11), p.2141-2147
• Main Authors: Fenger, Mogens, Wiik, Allan, Hoier-Madsen, Mimi, Lykkegaard, Jens J, Rozenfeld, Teresa, Hansen, Michael S, Samsoe, Bente Danneskjold, Jacobsen, Soren
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; Analytical, structural and metabolic biochemistry; Antibodies, Antinuclear - blood; Autoimmune Diseases - diagnosis; Biological and medical sciences; Child; Child, Preschool; Female; Fluorescent Antibody Technique - methods; Fundamental and applied biological sciences. Psychology; Humans; Immunoassay - methods; Immunoassays; Investigative techniques, diagnostic techniques (general aspects); Male; Medical sciences; Middle Aged; Rheumatic Diseases - diagnosis
• ISSN: 0009-9147; 1530-8561
• DOI: 10.1373/clinchem.2004.038422

Antinuclear antibodies (ANAs) are associated with several inflammatory rheumatic diseases. The aim of the present work was to evaluate enzyme immunoassays (EIAs) and compare them with classic immunofluorescent analysis (IFA) for the detection of ANA. Seven enzyme immunoassays were used in this study. All assays were applied as described by the manufacturers. Three populations were included in the study: (a) a population of patients with well-established autoimmune inflammatory disease (n = 102); (b) a population in which a rheumatic disease was diagnosed up to 5 years after an IFA was performed (n = 164); and (c) a population of consecutive outpatients suspected to have a rheumatic disease (n = 101). The current clinical diagnoses of the patients served as the standard against which performance of the assays was evaluated. In patients with well-established rheumatic disorders, the newly developed EIA in which HEp-2 extracts were included had sensitivities and specificities comparable to or in some instances better than the IFA. The assays without HEp-2 extracts included had significantly lower sensitivities and specificities. In the outpatient population, up to 51% of patients had positive ANA tests that did not correspond to classic ANA-associated disease. However, in the assays in which the HEp-2 extracts were not included, the false-positive rate was