Concordance of the Interferon-γ Release Assay (IGRA) and the Tuberculin Skin Test (TST) for the Screening of Tuberculosis Infection in the Inflammatory Rheumatic Disease (IRD) Population

Abstract

PURPOSE: Screening for active tuberculosis (TB) and latent TB infection (LTBI) is mandatory prior to the initiation of tumour necrosis factor-I± inhibitor therapy. However, no agreement exists on the best strategy for detecting LTBI in this population. We tested the diagnostic performance of tuberculin skin tes (TST) interferon-gamma (IFN-Î) inducible protein 10 (IP-10) and IFN-Î for detecting LTBI in rheumatic diseases patients. METHODS: 76 rheumatic diseases patients (26 rheumatoid arthritis,50 ankilosing spondilytis)were included.IP-10 levels were determined by enzyme-linked immunosorbent assay . TST was performed using the Mantoux method and was scored as positive if induration diameter was equal or > 5 mm . QFT-G was performed by measuring IFN-Î levels in whole blood treated with TB-specific antigens. RESULTS: 59.8 % TST-positive patients were defined as having LTBI. Agreement between TST, QFT and IP-10 results were assesmented.Agreement between QFT and TST was poor (k= 0,21), it was poor between IP-10 and TST( k=0,17),it was good between QFT and IP-10 (k= 0,64 ) CONCLUSIONS: we concluded that IGRA tests were more useful diagnostic methods than TST for detecting LTBI in inflammatory rheumatic patients.