title: Application of linear discriminant analysis in performance evaluation of extractable nuclear antigen immunoassay systems in the screening and diagnosis of systemic autoimmune rheumatic diseases.
abstract: This study applied a linear discriminant analysis model to evaluate the performance of 2 types of commercially available extractable nuclear antigen (ENA) immunoassays for the screening and diagnosis of systemic autoimmune rheumatic diseases (SARDs) in a large tertiary hospital reference laboratory: (1) an enzyme-linked immunosorbent assay (ELISA) and (2) a multiplex bead-based immunoassay (MPBI). The results of the study showed both ENA immunoassays had comparable sensitivity for the detection of SARDs compared with the antinuclear antigen immunofluorescence (ANA-IF) method (ANA-IF: 85.6%, ENA-ELISA: 91.5%, ENA-MPBI: 83.1%, pairwise comparisons with ANA-IF: P > .05). However, both ENA immunoassays offered improved specificity compared with the ANA-IF (ANA-IF: 24.2%; ENA-ELISA: 39.8%; ENA-MPBI: 53.1%; pairwise comparison with ANA-IF: P < .001). The use of a more specific screening immunoassay with comparable sensitivity to ANA-IF is important in a tertiary hospital with high prevalence of non-SARD immune diseases. Diagnostic performance of the ENA/dsDNA components by the MPBI and ELISA methods did not differ significantly (area under the curve [AUC], 81.0% vs 83.0%, respectively, P > .05), but the key ENA/dsDNA variables contributing to the discriminating power of the assays for the diagnosis of specific SARDs were reagent/method dependent.
authors.affiliation: Department of Pathology, Vancouver General Hospital, 855 West 12th Ave, Vancouver, BC, Canada V5Z 1M9. david.pi@vch.ca
authors.forename: David
authors.initials: D
authors.lastname: Pi
authors.forename: Monika Hudoba
authors.initials: MH
authors.lastname: de Badyn
authors.forename: Mike
authors.initials: M
authors.lastname: Nimmo
authors.forename: Rick
authors.initials: R
authors.lastname: White
authors.forename: Jason
authors.initials: J
authors.lastname: Pal
authors.forename: Patrick
authors.initials: P
authors.lastname: Wong
authors.forename: Carmen
authors.initials: C
authors.lastname: Phoon
authors.forename: Deidre
authors.initials: D
authors.lastname: O'Connor
authors.forename: Steven
authors.initials: S
authors.lastname: Pi
authors.forename: Kam
authors.initials: K
authors.lastname: Shojania
mesh_terms: D034961:Antigens, Nuclear / Q000276:immunology*; D001323:Autoantibodies; D001327:Autoimmune Diseases / Q000175:diagnosis* / Q000276:immunology; D016002:Discriminant Analysis; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007118:Immunoassay; D008403:Mass Screening; D008863:Microspheres; D011933:Reagent Kits, Diagnostic; D012216:Rheumatic Diseases / Q000175:diagnosis* / Q000276:immunology; D012680:Sensitivity and Specificity; D062606:Tertiary Care Centers
chemical_list: D034961:Antigens, Nuclear; D001323:Autoantibodies; D011933:Reagent Kits, Diagnostic