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Table 2 Comparison of manual and automated positive/negative discrimination assessing fluorescence intensity of 342 samples on ethN and formN patterns.

From: Automated interpretation of ANCA patterns - a new approach in the serology of ANCA-associated vasculitis

  ethN Automated interpretation by AKLIDES™
  n (%) - +/- + ++ +++ ++++
  - 133 (38.9) 1 (0.3) 0 (0) 0 (0) 0 (0) 0 (0)
  +/- 24 (7.0) 29 (8.5) 12 (3.5) 0 (0) 0 (0) 0 (0)
  + 0 (0) 4 (1.2) 44 (12.9) 11 (3.2) 0 (0) 0 (0)
  ++ 0 (0) 0 (0) 4 (1.2) 34 (9.9) 9 (2.6) 0 (0)
  +++ 0 (0) 0 (0) 0 (0) 3 (0.9) 16 (4.6) 5 (1.5)
  ++++ 0 (0) 0 (0) 0 (0) 0 (0) 0 (0) 13 (3.8)
Visual interpretation formN       
  n (%) - +/- + ++ +++ ++++
  - 225 (65.8) 8 (2.3) 2 (0.6) 2 (0.6) 0 (0) 0 (0)
  +/- 9 (2.6) 22 (6.4) 5 (1.5) 0 (0) 0 (0) 0 (0)
  + 0 (0) 5 (1.5) 25 (7.3) 6 (1.7) 0 (0) 0 (0)
  ++ 0 (0) 0 (0) 2 (0.6) 20 (5.8) 1 (0.3) 0 (0)
  +++ 0 (0) 0 (0) 0 (0) 1 (0.3) 6 (1.7) 0 (0)
  ++++ 0 (0) 0 (0) 0 (0) 0 (0) 0 (0) 3 (0.9)
  1. ANCA IIF patterns were first interpreted automatically with AKLIDES™ followed by manual reading with a routine fluorescence microscope. Both interpretation methods demonstrated very good agreement on ethN and formN (κ = 0.955, 95% confidence interval (CI): 0.944 to 0.965; κ = 0.929, 95% CI: 0.895 to 0.964; respectively). Quantitative fluorescence intensity threshold values for ethN: < 15 negative (-); ≥ 15 borderline (+/-) < 40; ≥ 40 weak positive (+) < 150; ≥ 150 positive (++) < 400; ≥ 400 strong positive (+++) < 700; ≥ 700 very strong positive (++++). Quantitative fluorescence intensity threshold values for formN: < 20 negative (-); ≥ 20 borderline (+/-) < 30; ≥ 30 weak positive (+) < 100; ≥ 100 positive (++) < 300; ≥ 300 strong positive (+++) < 600; ≥ 600 very strong positive (++++). ANCA, antineutrophil cytoplasmic antibody; ethN, ethanol-fixed neutrophils; formN, formalin-fixed neutrophils; IIF, indirect immunofluorescence.