Latent Tuberculosis Infection Screening for Laboratory Personnel Using Interferon-gamma Release Assay and Tuberculin Skin Test in Korea: An Intermediate Incidence Setting

Background: Though recent reports have indicated a higher prevalence of latent tuberculosis infection (LTBI) in laboratory personnel than in other healthcare workers, these studies included only a limited number of laboratory personnel. Methods: We have thus focused on the laboratory personnel, who had a high level of exposure to specimens from patients with TB. We recruited 173 laboratory personnel and performed QuantiFERON-TB Gold In-Tube test (QFT-G) and tuberculin skin test (TST). Results: QFT-G was positive in 21.4% of the enrolled laboratory personnel, and TST was positive in 33.3%. The agreement between the two tests was fair (kappa = 0.234). In multivariate analyses, household contact with TBpatients (P = 0.013), the laboratory sections of microbiology (P = 0.045) and chemistry/ immunology (P = 0.014) were shown to be significantly associated with positive QFT-G results. Conclusion: Our data show a high prevalence of TST and QFT-G positivity in laboratory personnel and emphasize the importance of LTBI screening for laboratory personnel. In BCG-vaccinated populations with an intermediate incidence setting, QFT-G seems to be superior to TST as a screening tool for the detection of LTBI. Further study, including results of follow-up tests will be helpful for confirmation of our findings. J. Clin. Lab. Anal. 25: 382-388, 2011. (C) 2011 Wiley Periodicals, Inc.