Background/Purpose: ANA IFA pattern may guide clinical evaluation by directing specific antibody testing. ICAP has defined consensus ANA IFA patterns and the level of competency required to identify and interpret them. This study was performed to determine laboratory practices in interpreting and reporting ANA IFA patterns.

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: Of 638 performing ANA by IFA and reporting a pattern, nearly 100% reported nucleolar, 99% homogeneous and speckled, and 96% centromere, all competent-level ICAP patterns. Only 42% reported nuclear dots (competent-level). 53% reporting nucleolar pattern further described expert-level subpatterns. Of 519 reporting speckled patterns, only 29% reported dense fine speckles, a competent-level pattern reportedly found in normals. “Other” speckled was reported by 44%. 4% did not report speckled pattern at all. Of those reporting nuclear dots, 86% differentiated many nuclear dots and 84% few nuclear dots. Nuclear envelope (expert-level) was reported by 18%. Competent-level cytoplasmic patterns were reported: golgi 69%, mitochondrial 65%, speckles 30%, 17% rods and rings, reticular 12% and polar 10%. Expert-level cytoplasmic patterns were reported: spindle apparatus 59%, centriole 55%, mid body 45%, and lysosomal 32%. Only 54% used an internal fluorescence intensity standard.

Conclusion: Pattern reporting practice is variable. Cytoplasmic pattern reporting is limited, possibly reflecting a lack of consensus that cytoplasmic patterns should be reported in an “antinuclear” antibody test. Failure to use an internal fluorescence intensity standard by nearly half of the laboratories may increase inter-assay and inter-observer variation in the threshold for staining positivity and in titer determination.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/variability-in-icap-international-consensus-on-ana-patterns-pattern-reporting-in-testing-for-antinuclear-antibodies-ana-by-indirect-immunofluorescence-assay-ifa/