QuantiFERON-TB Gold In-Tube test for diagnosis of latent tuberculosis (TB) infection in solid organ transplant candidates: a single-center study in an area endemic for TB

Abstract

Background. The prevalence of Mycobacterium tuberculosis in transplant recipients is estimated to be 50 times higher than in the general population, with a mortality rate of around 40%. Diagnosis and treatment of latent tuberculosis (TB) infection (LTBI) is an essential strategy for TB control. In this study we compared the QuantiFERON-TB Gold In-Tube test (QFT) with the tuberculin skin test (TST) for detection of LTBI in solid organ transplant (SOT) candidates. Patients and methods. Between March 2008 and September 2011, 187 transplant candidates, who were referred to the transplant clinic of Imam-Khomeini Hospital, were enrolled in the study. Patients were screened for LTBI with both QFT and TST. Twenty-three patients (12.3%) were excluded for failure to follow up. Concordance between the 2 tests, and variables associated with test discordance were assessed. Results. The mean age of patients was 40 years (range: 11-65) and male-to-female ratio was 1.2 (88/76). TST and QFT were positive in 26 (15.9%) and 33 (20.1%) patients, respectively. Five cases (3.1%) had indeterminate QFT. Overall agreement between QFT and TST was about 80% (k = 0.32, P-value = 0.0001). Conclusion. Considering the fair overall agreement between the 2 tests, and greater ease of the QFT from the patient's point of view, QFT is recommended for detection of LTBI in SOT candidates.