Validity of interferon-γ-release assays for the diagnosis of latent tuberculosis in haemodialysis patients

P>Haemodialysis patients are at higher risk of developing active tuberculosis (TB) infection. However, tuberculin skin tests (TST) have limitations and the diagnostic usefulness of interferon-gamma-release assays (IGRAs) remains unclear in immunocompromised hosts including haemodialysis patients. Haemodialysis patients were enrolled from a dialysis centre in Korea, an intermediate TB-burden country with a high bacille Calmette-Guerin (BCG) vaccination rate. The QuantiFERON-Gold TB In tube test (R) (QFT) and the T-SPOT TB test (R) (TSPOT) were performed, along with the TST. We stratified patients to low- and high-risk groups, according to the risk factors for latent TB. Association between each of the three diagnostic tests and the risk of latent TB was analysed. One hundred and sixty-seven patients were enrolled. The positive rates for the TST, the QFT and TSPOT were 23.5, 45.9 and 60.4%, respectively. Previous BCG vaccination increased the TST-positive rate in the low-risk group (OR 4.438), whereas it affected neither QFT nor TSPOT. The positive QFT rates were 41.2 and 62.5% in the low- and high-risk groups, respectively. The QFT was associated with the high-risk group (OR 2.578), whereas the TST was not. The positive TSPOT rates were 58.9 and 65.7% in the low- and high-risk groups, respectively. The frequency of indeterminate results was higher for the QFT (12.6%) compared with the TSPOT (4.8%). In conclusion, the IGRAs can be useful for the diagnosis of latent TB infection in haemodialysis patients.