Factors Influencing Discrepancies Between the QuantiFERON-TB Gold in Tube Test and the Tuberculin Skin Test in Korean Patients with Rheumatic Diseases

• Published in: Seminars in arthritis and rheumatism 2013-02, Vol.42 (4), p.424-432
• Main Authors: Kim, Jae-Hoon, MD, Cho, Soo-Kyung, MD, PhD, Han, Minkyung, BS, Choi, Chan-Bum, MD, PhD, Kim, Tae-Hwan, MD, PhD, Jun, Jae-Bum, MD, PhD, Bae, Sang-Cheol, MD, PhD, MPH, Yoo, Dae-Hyun, MD, PhD, Sung, Yoon-Kyoung, MD, PhD, MPH
• Format: Article
• Language: English
• Subjects: Adult; Aged; Asian Continental Ancestry Group; Female; Humans; latent tuberculosis infection; Male; Middle Aged; QuantiFERON-TB gold in tube test; Republic of Korea; Retrospective Studies; rheumatic disease; Rheumatic Diseases - complications; Rheumatology; tuberculin skin test; Tuberculin Test - methods; Tuberculosis - complications; Tuberculosis - diagnosis; tumor necrosis factor inhibitor
• ISSN: 0049-0172; 1532-866X
• DOI: 10.1016/j.semarthrit.2012.07.001

Objectives To estimate the positivity and agreement between QuantiFERON-tuberculosis (TB) gold in tube test (QFT-GIT) and tuberculin skin test (TST) according to underlying rheumatic diseases and to identify the influencing factors on discrepancies between the 2 tests. Methods Among the 757 patients who underwent both QFT-GIT and TST simultaneously from September 2008 to November 2010, patients with indeterminate QFT-GIT results ( n = 21), with active ( n = 11) or suspicious ( n = 1) findings for tuberculosis on a chest radiograph, were excluded. Finally, 724 patients were recruited for this study: 497 patients with rheumatoid arthritis (RA), 198 with ankylosing spondylitis (AS), and 29 with juvenile rheumatoid arthritis (JRA). The agreement between the 2 tests was estimated by Cohen's κ and factors influencing discrepancies were identified using multivariate analysis. Results The positivity of QFT-GIT was higher in RA than AS or JRA (30.2%, 16.2%, and 3.4%, respectively). In contrast, TST positivity was highest in AS compared to RA and JRA (45.5%, 28.2%, and 17.2%, respectively). The agreement between the 2 tests was low in all patients (κ = 0.285). The only predictor of a discrepancy between the 2 tests was older age. Factors associated with discordant QFT-GIT-negative/TST-positive results were female [odds ratio (OR) = 2.33, confidence interval (CI) 1.11 to 4.89] and AS (OR = 3.12, CI 1.44 to 6.79), whereas a discordant QFT-GIT-positive/TST-negative result was associated with glucocorticoid use (OR = 2.44, CI 1.24 to 4.81). Conclusions The agreement between the 2 tests is low; therefore, it would be better to perform both tests than to use any 1 test alone for the detection of LTBI in TB-endemic regions. Female and underlying AS are related to being QFT-GIT-negative/TST-positive, and the use of glucocorticoid is associated with being QFT-GIT-positive/TST-negative.