Date: Sunday, November 5, 2017
Session Type: ACR Poster Session A
Session Time: 9:00AM-11:00AM
Background/Purpose: A 2010 American College of Rheumatology position paper designated indirect immunofluorescence assay (IFA) on HEp-2 cells the “gold standard” for ANA testing and that laboratories performing other methods should state the method used and describe its performance parameters. This study was performed to determine laboratory practices in ANA testing.
Methods: Supplemental questions were sent to laboratories participating in the College of American Pathologist’s proficiency testing program for ANA as part of the Special Immunology S-A Survey 2016 to determine the practice of ANA testing. Of 5847 kits distributed, 1206 (21%) responded to the questionnaire; 942 were in the United States and 264 were international.
Results: ANA screening method varied: 56% IFA, 21% ELISA, 12% multi-bead immunoassay, and 18% “other” methods. Ordering test name indicated method used in only 32%; only 39% stated method used on the report. Of 644 laboratories, 80% used HEp-2 substrate, 18% HEp-2000 (HEp-2 cell line engineered to overexpress SSA), and 2% “other.” Slides were prepared manually (67%) or on an automated platform (33%), and examined by direct microscopy (84%) or images captured by an automated platform (16%). IFA patterns were interpreted by personnel in 95% of laboratories; <1% used automated image capture and analysis solely; 4% interpreted images both by personnel and an automated platform. 97% of 641 laboratories reporting ANA by IFA provided a titer. Only 51% reported a positive result at the traditional 1:40 dilution. Titer was reported to endpoint routinely by 43%, only upon request by 23%, or never by 35%. 8% did not report dual patterns. Of those reporting multiple patterns, 24% did not report a titer with each pattern.
Conclusion: Only slightly more than half of testing laboratories utilize the ACR “gold standard” IFA method with HEp-2 cell substrate.
To cite this abstract in AMA style:Naides SJ, Genzen J, Abel G, Bashleben C, Ansari MQ. Variability in Method of Testing for Antinuclear Antibodies (ANA): A Survey of Participants in the College of American Pathologist’s (CAP) Proficiency Testing Program [abstract]. Arthritis Rheumatol. 2017; 69 (suppl 10). https://acrabstracts.org/abstract/variability-in-method-of-testing-for-antinuclear-antibodies-ana-a-survey-of-participants-in-the-college-of-american-pathologists-cap-proficiency-testing-program/. Accessed January 19, 2019.
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/variability-in-method-of-testing-for-antinuclear-antibodies-ana-a-survey-of-participants-in-the-college-of-american-pathologists-cap-proficiency-testing-program/