• Pediatric Infection and Vaccine
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• v.20 no.1
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• pp.17-27
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• 2013

Purpose: Recently, two tests are commercially available for the identification of latent tuberculosis infection (LTBI): tuberculin skin test (TST) and interferon-${\gamma}$ release assay (IGRA). Due to its false positiveness, TST tends to be preferred by IGRA until now. In our study, we simultaneously performed both TST and QuantiFERON$^{(R)}$-TB Gold In-Tube (QFT-GIT) and compared their results. Methods: TST and QFT-GIT were done for the diagnosis of LTBI among children who visited pediatric out-patient clinic at St. Vincent's Hospital, The Catholic University of Korea from February of 2007 to May of 2008. The study group was stratified into two groups in terms of whether there was intrafamilial contact or not. Results: Out of total 35 children, 29 were tuberculosis (TB)-exposed cases and the remainders were diagnosed as clinical pulmonary TB. Among these 29 children, TST was positive 38.9% (7/18) for the intrafamilial and 45.5% (5/11) for the nonintrafamilial, and at the same time, the result for QFT-GIT was positive 5.6% (1/18) and 9.1% (1/11), respectively which implies that TST was more sensitive than QFT-GIT. Among 29 TB-exposed cases, 26 initially went through TST and QFTGIT together on their first visit to out-patient clinic, and 15 continued the follow-up tests. Out of total 41 cases collected, the agreement (known as kappa value) was 0.063 which was relatively low. Including 6 cases with pulmonary TB who were all positive for TST and only 5 being positive for QFT-GIT, the final kappa value was 0.334. Conclusion: In our study, the agreement for TST and QFT-GIT was low, and the majorities were almost the cases of positive TST. In current situation with lacking a gold standard test and limited data on children to adolescents, this result is quite alarming that the recent trend tends to replace TST by QFT-GIT when diagnosing LTBI.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.27 no.3
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• pp.238-244
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• 2017

Objectives: The major objective of this study was to investigate the prevalence of and risk factors for latent tuberculosis infection (LTBI) among employees at a workers' compensation hospital. Methods: Among the 394 employees at Incheon Hospital, 362 were enrolled in the study. An interferon-gamma release assay(IGRA) for diagnosis of LTBI was performed using QuantiFERON$^{(R)}$ TB Gold In-Tube(QFT-IT). Risk factors for LTBI were analyzed using logistic regression analysis. Results: The overall prevalence of LTBI was 32.0%(116/362). The non-medical departments have a significantly high prevalence compared to medical departments(39.7% vs 23.2%). In multivariate logistic regression analysis, experience working in the pneumoconiosis hospital(OR, 3.6; 95% CI, 1.3-10.3) was associated with development of LTBI. Conclusions: Korean guidelines for the management of tuberculosis recommend annual regular health examinations for TB and LTBI for health care workers(HCWs). Considering the high prevalence of and risk factors for LTBI among non-HCWs, it suggests a need for annual regular health examinations for TB and LTBI for all employees at workers' compensation hospitals, including pneumoconiosis hospitals.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.29 no.3
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• pp.289-297
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• 2019

Objectives: To identify the positive rate of and the risk factors associated with latent tuberculosis infection(LTBI) in mine workers, the objectives of the present study evaluated those among former mine workers. Methods: Between January 2015 and May 2017, former male mine workers who had been subjects for epidemiology research for work-related chronic obstructive pulmonary disease(COPD) and had received QuantiFERON-$TB^{(R)}$ Gold In-Tube(QFT-GIT) from the Institute of Occupation and Environment(IOE) under Korea Workers' Compensation and Welfare Service(KCOMWEL) were selected as the study subjects. To identify significant variables for increased risk of LTBI, logistic regression analysis was performed. Results: A total of 736 male former mine workers were selected as study subjects. The positive rate of LTBI among subjects was 69.2%(509/736). The current smoking[odds ratio(OR), 2.3; 95% confidence interval(CI), 1.1-4.9], COPD(OR, 1.4; 95% CI, 0.9-2.3), department loading(OR, 1.8; 95% CI, 0.9-3.4) and mining(OR, 1.5; 95% CI, 0.9-2.5), and working duration of over 20(OR, 1.6; 95% CI, 0.9-3.1) and over 30 years(OR, 2.2; 95% CI, 0.9-4.9) were associated with increased risk of LTBI. The interferon-gamma(IFN-${\gamma}$) level after stimulation with Mycobacterium tuberculosis(MTB)-specific antigens showed a significantly negative correlation with age(r=-0.126). Conclusions: The present study determined that the high positive rate of LTBI among mine workers was associated with not only the host factors but also the occupational exposure to mine dust.

• Tuberculosis and Respiratory Diseases
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• v.68 no.5
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• pp.280-285
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• 2010

Background: $QuantiFERON^{(R)}$-TB Gold In Tube (QFT-G IT) has been used for diagnosing latent tuberculosis infection and active tuberculosis (TB) since 2007. However, there has not been enough data on QFT-G IT for universal use in children. In this study, we evaluated the clinical usefulness of the QFT-G IT in pediatric practice. Methods: We retrospectively reviewed the clinical records of 70 patients younger than 18 years of age who had taken QFT-G IT and had a tuberculin skin test (TST) between July 2007 and July 2009 at Wonju Christian Hospital. The subjects were divided into two groups, asymptomatic TB exposure group and disease group. Four patients who were taking immunosuppressants during the study period were excluded. Results: A total of 66 immunocompetent children were included in this study. Among 27 asymptomatic children who had contact histories of TB, 6 (22.2%) were found to be positive by QFT-G IT. Eleven (40.7%) and 5 (18.5%) children were found to be positive by TST with cutoff values of ${\geq}5mm$ and ${\geq}10mm$, respectively. Agreement was fair to good between QFT-G IT and TST (${\kappa}=0.59$: cutoff value ${\geq}5mm$, ${\kappa}=0.7$: cutoff value ${\geq}10mm$). In disease group, 14 patients (35.9%) were diagnosed with active tuberculosis, 8/14 (57.1%) were positive on TST and 9/14 (64.3%) on QFT-G IT. The positive rate of acid-fast bacilli smear, TB-polymerase chain reaction, and culture for tuberculosis was 11% (1/9), 27.3% (3/11) and 33.3% (3/9), respectively. Conclusion: Our data support that the QFT-G IT can be used as an additional diagnostic tool for latent and active tuberculosis infection in children.

• Clinical and Experimental Pediatrics
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• v.51 no.9
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• pp.971-976
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• 2008

Purpose : Surveillance for detecting and managing latent tuberculosis infection (LTBI) is a key component of tuberculosis control. The classic surveillance tool, the tuberculin skin test (TST), may have some limitations when used in the Bacillus Calmette-$Gu{\acute{e}}rin$ (BCG)-vaccinated population. The object was to perform a blood test $QuantiFERON^{(R)}$-TB Gold In Tube (QFT-G IT) based on the detection of interferon-$\gamma$ ($IFN-{\gamma}$) released by T cells in response to Mycobacterium tuberculosis-specific antigens, and to compare the efficacy of this new diagnostic tool for LTBI with that of TST. Methods : For six months, between October 1, 2006 and April 30, 2007, data were collected from 111 patients under 15 years of age at Severance Children's Hospital. TST and QFT-G IT tests were performed with children with or without contact histories of tuberculosis. In addition to these tests, we examined comparative data from 29 adults who had tuberculosis, to detect false negative rates in the QFT-G IT method. Results : Thirty-three children had household contact histories. In this group, 15% and 42% of cases were found to be positive using the QFT-G IT assay and TST, respectively. Agreement was low between these two tests (${\kappa}=0.39$). In the adult active tuberculosis group, the QFT-G IT false negative rate defined as a positive culture and a negative QFT-G IT result was 12.5%. Conclusion : In diagnosing LTBI in children, the usefulness of a whole-blood $IFN-{\gamma}$ assay employing TB-specific antigens will be revealed only by examining additional longitudinal clinical data; this study serves as a starting point in that process.