Comparison of the tuberculin skin test and interferon-γ release assay for the diagnosis of latent tuberculosis infection before kidney transplantation

Purpose: The evaluation of latent tuberculosis infection (LTBI) is recommended before kidney transplantation. The interferon-γ release assay has been reported to be more specific than the tuberculin skin test (TST) for detecting LTBI. We compared the TST and QuantiFERON-TB Gold In-Tube test (QFT-GIT) for the screening for LTBI and determined the agreement between the two tests in renal transplant recipients before transplantation. Methods: Adult patients who were evaluated for renal transplantation between May 2010 and February 2012 at Severance Hospital in South Korea were prospectively enrolled. We performed TST and QFT-GIT. Results: Of the 126 patients, 23 (19.3 %) had positive TST results and 53 (42.1 %) had positive QFT-GIT results. Agreement between the TST and QFT-GIT was fair (κ = 0.26, P < 0.001). The induration size of TST was significantly correlated with a positive rate of QFT-GIT (P = 0.015). Age (odds ratio [OR] 1.08, 95 % confidence interval [CI] 1.03-1.13, P = 0.003), male sex (OR 2.73, 95 % CI 1.17-6.38, P = 0.021), and risk for LTBI (OR 4.62, 95 % CI 1.15-18.64, P = 0.031) were significantly associated with positive QFT-GIT results. For positive TST results, only male sex was associated (OR 4.29, 95 % CI 1.40-13.20, P = 0.011). Conclusion: The positivity for QFT-GIT was higher than the positivity for TST, and QFT-GIT more accurately reflected the risk for LTBI. However, a further longitudinal study is needed in order to confirm that the QFT-GIT test can truly predict the development of TB after renal transplantation.