Discrepancy between the Tuberculin Skin Test and the T-SPOT.TB for Detecting Latent Mycobacterium tuberculosis Infection in Patients with Rheumatoid Arthritis / 대한류마티스학회지

ABSTRACT

OBJECTIVE: To evaluate concordance rate between tuberculin skin test (TST) and T-SPOT.TB (T-SPOT) for detecting latent tuberculosis in patients with rheumatoid arthritis (RA) received disease modifying antirheumatic drugs (DMARDs) and/or immunosuppressant. METHODS: Fifty four patients with RA refractory to conventional DMARDs and planned ahead to be received tumor necrosis factor-alpha (TNF-alpha) blockade were enrolled in this study. The TST was performed by Mantoux method. Over 10 mm induration size was considered to be positive in the TST. The peripheral blood were collected from all patients and used for the T-SPOT. RESULTS: Only six patients (11.11%) had a positive TST, and 48 patients (88.89%) had a negative TST. The mean TST values were 13.51+/-3.51 mm (range 10~19 mm) in TST (+) group and 2.50+/-3.12 mm (range 0~9 mm) in TST (-) group, respectively. T-SPOT was indeterminate in 7 patients (12.96%). Twenty-five patients (53.19%) had a positive result, and 22 patients (46.81%) had a negative result in 47 patients determinated with T-SPOT. There was poor overall agreement between results of TST and T-SPOT (p=0.194). CONCLUSION: There was no concordance between TST and T-SPOT in patients with RA received DMARDs and/or immunosuppressant. Therefore, the results of TST should be interpreted with caution, taking into consideration of the result of T-SPOT in patients with RA who are prone to having false negative of TST.