title: TEST performance of a myositis panel in a clinical immunology laboratory in New South Wales, Australia.
abstract: BACKGROUND
  There is increasing recognition of a clinico-serological correlation between the idiopathic inflammatory myopathies and myositis-specific autoantibodies (MSA). We review the use of a line immunoassay-based myositis panel incorporating both MSA and myositis-associated autoantibodies (MAA) in a selected population of patients.
  
  
  METHODS
  A retrospective analysis of patients with myositis panel assays performed in 2013 were reviewed and compared against clinical diagnoses.
  
  
  RESULTS
  A total of 96 patient samples were evaluated, the clinical indications include 60 patients with suspected idiopathic inflammatory myositis (IIM), 24 patients with suspected interstitial lung disease (ILD) and 12 patients with suspected systemic autoimmune disease (SAD). In the myositis group, there were 21 patients diagnosed with IIM and 18 patients diagnosed with IIM had a positive myositis panel. Of the 39 patients without IIM, nine of these patients had a positive myositis panel. In the ILD group, 10 of 24 patients had a positive myositis panel; of these, two were diagnosed anti-synthetase syndrome (ASS) and five patients with ILD. In the suspected SAD group, three had positive myositis panel and all did not appear associated with their final diagnoses. In patients with a clinical diagnosis of IIM or ILD-associated SAD, four patients with anti-PL-12 were detected, three patients with anti-signal recognition protein, two patients with anti-Jo-1, and two patients with anti-Mi2.
  
  
  CONCLUSIONS
  The myositis panel is an objective investigative modality with a sensitivity of 80.00% and a specificity of 75.76% in a setting of high pretest clinical suspicion.
authors.affiliation: Rheumatology, Allergy and Immunology, Tan Tock Seng Hospital, Singapore. teck_choon_tan@ttsh.com.sg.
authors.forename: Teck Choon
authors.initials: TC
authors.lastname: Tan
authors.affiliation: Clinical Immunology, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia.
authors.forename: Louise
authors.initials: L
authors.lastname: Wienholt
authors.affiliation: Clinical Immunology, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia.|Sydney Medical School University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Stephen
authors.initials: S
authors.lastname: Adelstein
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000486:Allergy and Immunology; D001323:Autoantibodies / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D019411:Clinical Laboratory Techniques; D005260:Female; D006801:Humans; D007118:Immunoassay; D008297:Male; D008875:Middle Aged; D009220:Myositis / Q000097:blood / Q000175:diagnosis* / Q000276:immunology; D009517:New South Wales; D011237:Predictive Value of Tests; D011379:Prognosis; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012698:Serologic Tests
chemical_list: D001323:Autoantibodies; D015415:Biomarkers
keywords: myositis and related syndromes, Clinical aspects; myositis and related syndromes, epidemiology