Current issues of standardization of antinuclear antibodies’ detection by indirect immunofluorescence on HEp-2 cells

Abstract

Background. Antinuclear antibodies (ANA) are a group of antibodies that target nuclear and cytoplasmic antigens. Testing for ANA using an immunofluorescence assay (IFA) on HЕp-2 cell (IFA-HEp-2) is a screening test for the diagnosis of systemic autoimmune rheumatic diseases, druginduced lupus erythematosus, autoimmune liver diseases, juvenile idiopathic arthritis. In routine ANA testing final report forms bears important, but unstandardized variables (e. g., screening and final titers of ANA, coding of glow types, the procedure for performing confirmatory tests). Aim of the study. Develop a standard report form for IFA-HEp-2 testing results.Material and methods. Survey of 10 immunological and clinical diagnostic laboratories using the ICAP questionnaire adapted by the Working Group on Standardization of the definition of ANA by the IFA-HEp-2 method (Committee on Immunology of the Association ‘Federation of Laboratory Medicine’).Results. According to the results of a survey: most of the participants use a screening dilution of serum 1:160; indicates the maximum end titer of antinuclear factor (ANF), cytoplasmic staining; identifies staining types (including AC encoding); considers it mandatory to make confirmatory tests to detect ANA to individual nuclear antigens in ANF-positive patients, but does not provide a list of this tests in the results form; describes ANF titer for each of the detected glows separately; designates ANF titers using a colon and does not give a clinical interpretation of the results. Based on interlaboratory consensus, ICAP recommendations and the requirements of ISO 15189, the standard report form for IFA-HEp-2 testing results was developed.Conclusions. To achieve high quality of interaction between clinical diagnostic/immunological laboratories and clinical departments of health care facilities, it’s necessary to introduce into practice a standard form for IFA-HEp-2 testing results, developed relying on modern clinical recommendations and interlaboratory consensus.