title: Clinical diagnostic performance of different methods for the detection of antibodies to extractable nuclear antigens in connective tissue diseases: a cohort study.
abstract: BACKGROUND
  Different methods for anti-ENA identification have been used. This can lead to confusion regarding the interpretation of the test results in clinical practice. Some studies have reported differences in sensitivity and specificity, but few compare clinical outcomes. Based on that, our aim was to compare the performance characteristics of various methods commonly used to detect anti-ENA antibodies in the sera of patients suspected to have connective tissue diseases (CTDs).
  
  
  METHODS
  189 patients with orders for anti-ENA were analyzed. Three common methods were used: DID, ELISA, and HA. Sensitivity, specificity, PPV, NPV, and LR were calculated using CTDs as the reference standard.
  
  
  RESULTS
  69.3% of the patients had a CTD and 32.8% had SLE. Sensitivity and specificity, respectively, according to the technique were: ELISA (50.0% - 78.9%); DID (31.3% - 89.5%); HA (40.9% - 87.7%). PPV were: 88.5% (HA), 87.2% (DID) and 84.6% (ELISA), and NPV were: 40.5% (ELISA), 39.1% (HA) and 36.2% (DID).
  
  
  CONCLUSIONS
  Based on the very similar predictive test values, we believe that, at least in a moderate to high pretest probability, in our methodological scenario, there are no significant differences in the interpretation of test results when using ELISA, HA, and DID for anti-ENA detection.
authors: Division of Rheumatology, Department of Internal Medicine, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
authors: Priscila Schmidt
authors: PS
authors: Lora
authors: Claudia Cilene Fernandes Correa
authors: CC
authors: Laurino
authors: Bruno Silveira
authors: BS
authors: Becker
authors: Odirlei André
authors: OA
authors: Monticielo
authors: João Carlos Tavares
authors: JC
authors: Brenol
authors: Ricardo Machado
authors: RM
authors: Xavier
mesh_terms: D000328:Adult; D000974:Antibodies, Antinuclear / Q000097:blood*; D000918:Antibody Specificity; D001324:Autoantigens / Q000276:immunology; D003240:Connective Tissue Diseases / Q000097:blood* / Q000276:immunology; D004264:DNA Topoisomerases, Type I; D003882:Dermatomyositis / Q000097:blood / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006386:Hemagglutination Tests; D006801:Humans; D005779:Immunodiffusion; D016013:Likelihood Functions; D008180:Lupus Erythematosus, Systemic / Q000097:blood / Q000276:immunology; D008297:Male; D008875:Middle Aged; D009687:Nuclear Proteins / Q000276:immunology; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012261:Ribonucleoproteins / Q000276:immunology; D012680:Sensitivity and Specificity; D000097585:SS-B Antigen; D000099207:SS-A Antigen
chemical_list: D000974:Antibodies, Antinuclear; D001324:Autoantigens; D004264:DNA Topoisomerases, Type I; D009687:Nuclear Proteins; D012261:Ribonucleoproteins; D000097585:SS-B Antigen; D000099207:SS-A Antigen; C035356:SS-A antibodies; C035357:SS-B antibodies; C048100:Scl 70 antigen, human