2022 updates of the International Consensus on ANA Patterns (ICAP)
By Edward K. L. Chan, Wilson M. Cruvinel and Luis E. C. Andrade

The indirect immunofluorescence assay on HEp-2 cells (HEp-2 IFA), commonly known as the antinuclear antibody (ANA) test, is used worldwide in the screening for autoantibodies that are valuable biomarkers for the diagnosis of systemic autoimmune diseases.

As a key feature of this test, the immunofluorescence pattern provides valuable information on the putative autoantibody specificity in the sample, and this serves as guidance for further testing in antigen-specific immunoassays.

ICAP is an initiative of the Autoantibody Standardization Committee, a subcommittee of the IUIS Quality Assessment and Standardization Committee. The goals of ICAP are to promote the harmonization of HEp-2 IFA pattern nomenclature, refine interpretation, and emphasize immunological associations of IFA patterns to optimize their usage in patient care. The ICAP website provides the consensus classification of over 30 HEp-2 IFA patterns with illustrative images and detailed information on the immunological and clinical relevance of each pattern.

In 2021, a significant revision was made to the classification tree based in part on feedback from the user community (see figure below). To date, with translation into 19 languages, we have over 340,000 views per year from users across >180 countries. In the last 3 years, our predominant users are young (18 – 34 years old, 43%), females (60%), and with 39% access via mobile phones, suggesting that ICAP has reached the next generation of IFA users.