Session Type: Poster Session (Sunday)
Session Time: 9:00AM-11:00AM
Background/Purpose: Indirect immunofluorescence (IF) is the recommended initial test for detection of antinuclear antibodies (ANA) by the American College of Rheumatology (Ann Rheum. Dis 69:1420-2), (Clin. Immunol. 124:18-21). Because the staining pattern does not identify the responsible autoantibody, additional testing using Flow Cytometry-based Recombinant Antigen Assays (FCA) is required. We were interested in assessing the correlation of this method for ANA detection with the results of specific autoantibodies identified by FCA at our institution between 2012-2019.
Methods: 5,474 instances of simultaneous testing with ANA by IF and FCA were identified. All tests were performed in house (SUNY Upstate, Syracuse, NY). Positive autoantibody detection by FCA for dsDNA, anti-Smith, centromere, histone, RNP, Scl-70, SSA, and SSB were individually compared to results of ANA by IF. Sensitivities, specificities, positive and negative predictive values were assessed by 2-tailed Chi-square tests using GraphPad software.
Results: Of 396 positive dsDNA results, 223/396 were associated with a homogeneous pattern and 173/396 were not (sensitivity: 56%; p< 0.0007 relative to anti-Smith, p< 0.0021 relative to RNP and p< 0.0001 to all others). Anti-Smith antibodies had association with speckled pattern in 171/245 instances (70%) while 74/245 (30%) did not (statistical significance only achieved in comparison to dsDNA (p< 0.0007 and centromere (0.0009)). There were 562 instances of multiple positive autoantibodies detected by FCA associated with positive IF, and an additional 17 instances of multiple positive autoantibodies associated with negative IF.
Conclusion: This analysis of lupus patients suggests that quality control issues likely exist when IF is used for ANA screening given the high number of negative homogeneous and speckled patterns when compared to positive dsDNA and Sm autoantibody detection by FCA.
To cite this abstract in AMA style:Dziamski K, Perl A. Quality Control of Antinuclear Antibody Detection by Indirect Immunofluorescence and Flow Cytometry-based Recombinant Antigen Assays [abstract]. Arthritis Rheumatol. 2019; 71 (suppl 10). https://acrabstracts.org/abstract/quality-control-of-antinuclear-antibody-detection-by-indirect-immunofluorescence-and-flow-cytometry-based-recombinant-antigen-assays/. Accessed July 15, 2020.
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/quality-control-of-antinuclear-antibody-detection-by-indirect-immunofluorescence-and-flow-cytometry-based-recombinant-antigen-assays/