AB0269 RHUMATOID FACTORS ISOTYPES DIAGNOSTIC SENSITIVITY AND SPECIFICITY IN RHUMATOID ARTHRITIS PATIENTS IN TUNISIA

Background Rheumatoid factor (RF) is a well-established marker for the diagnosis and classification of rheumatoid arthritis (RA). Most studies have evaluated IgM RF or isotype-nonspecific total tests. Objectives We importance isotype in this study. Methods An international cohort consisting samples from 52 RA patients 57 suffer other rheumatologic deseases were tested IgA, IgG RF. Clinical biological data collected. Results IgM, positive 96,15%, 88,46% 17,3% respectively. The sensitivity was lowest 16,7%, IgA lower than (87,8% vs 95,9%). specificity (29,8 %vs 61,4 89,4% respectively). Double positivity had higher (92.6% vs. 29,8% 89,4%). However, combined RF, ACPA either antibody. Conclusion showed combination with did not improve classification. Combined (IgA-RF/IgM-RF/ACPA) increased specificity. REFERENCES: NIL. Acknowledgements: Disclosure Interests None Declared.