• 대한의생명과학회지
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• 제24권2호
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• pp.138-142
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• 2018

The incidence of tuberculosis (TB) in the Republic of Korea remains high when compared to the incidence in other Organization for Economic Cooperation and Development (OECD) countries. The prompt diagnosis and effective treatment of latent TB infection (LTBI) are very important in terms of controlling the burden of TB. The tuberculin skin test (TST) has long been the "gold standard" assay for the diagnosis of LTBI. However, it can show false positive results due to Bacille Calmette-$Gu{\acute{e}}rin$ (BCG) vaccination and infection with many environmental nontuberculous mycobacteria (NTM). The interferon gamma release assay (IGRA) using Mycobacterium tuberculosis (MTB)-specific antigens, was developed for the detection of LTBI. The QuantiFERON-TB Gold In-Tube assay is one of the most commonly used forms of the IGRA. In order to compare the diagnostic efficacy of the TST and IGRA in relation to LTBI among BCG-vaccinated healthy donors, whole blood samples were collected from 51 participants, and the results of the TST and IGRA were compared. Of the 51 cases, 18 cases (35.3%) were positive and 33 cases (64.7%) were negative when using the TST, while four cases (7.8%) were positive and 47 cases (92.2%) negative when using the IGRA. There was no correlation between the size of the induration in the TST and the $IFN-{\gamma}$ protein level. In conclusion, the TST showed higher cross-reactivity among the BCG-vaccinated healthy participants, therefore, the IGRA might be the most suitable assay for the rapid screening of LTBI in BCG-vaccinated healthy population, or for TB contact investigation.

• Tuberculosis and Respiratory Diseases
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• 제81권1호
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• pp.59-72
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• 2018

Background: It remains uncertain if $interferon-{\gamma}$ release assays (IGRAs) are superior to the tuberculin skin test (TST) for the diagnosis of active tuberculosis (TB) or latent tuberculosis infection (LTBI) in immunosuppressed populations including people with human immunodeficiency virus (HIV) infection. The purpose of this study was to systematically review the performance of IGRAs and the TST in people with HIV with active TB or LTBI in low and high prevalence TB countries. Methods: We searched the MEDLINE database from 1966 through to January 2017 for studies that compared results of the TST with either the commercial QuantiFERON-TB Gold in Tube (QFTGT) assay or previous assay versions, the T-SPOT.TB assay or in-house IGRAs. Data were summarized by TB prevalence. Tests for concordance and differences in proportions were undertaken as appropriate. The variation in study methodology was appraised. Results: Thirty-two studies including 4,856 HIV subjects met the search criteria. Fourteen studies compared the tests in subjects with LTBI in low TB prevalence settings. The QFTGT had a similar rate of reactivity to the TST, although the first-generation version of that assay was reactive more commonly. IGRAs were more frequently positive than the TST in HIV infected subjects with active TB. There was considerable study methodology and population heterogeneity, and generally low concordance between tests. Both the TST and IGRAs were affected by CD4 T-cell immunodeficiency. Conclusion: Our review of comparative data does not provide robust evidence to support the assertion that the IGRAs are superior to the TST when used in HIV infected subjects to diagnose either active TB or LTBI.

• 대한임상검사과학회지
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• 제48권3호
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• pp.225-229
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• 2016

결핵이란 결핵균에 의한 만성 감염질환으로 결핵균이 포함된 비말액을 통해 공기감염을 일으킨다. 대부분의 결핵감염자는 전염력이 없는 잠복감염상태만 유지하나 10%의 감염자 중 절반은 감염 후 1~2년 안에 발병하게 된다. 결핵감염자와 접촉이 있는 학생 74명을 대상으로 결핵 감염자 접촉관련 사전 조사 및 흉부 X-선 검사, TST 검사 및 IGRA 검사를 실시하였다. 1차 TST 검사에서 양성자는 9명, 음성은 65명으로 나타났으며, 음성 판독자는 2차 TST검사를, 양성 판독자는 IGRA 검사를 실시하였다. 1차 TST 양성자 9명 중 IGRA 검사에서 3명이 양성자로 나와 잠복 결핵감염 치료를 실시하였다. 1차 TST결과 음성자에 대한 재확인 TST 검사는 1차와 차이가 없었다. 결론적으로 잠복결핵감염율은 74명중 3명으로 4.05%로 나타났고, 잠복결핵감염자 색출을 위해서 다른 그룹에 대한 조사도 필요하다.

• Pediatric Infection and Vaccine
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• 제23권2호
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• pp.94-101
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• 2016

목적: 대학병원에 근무하던 중 활동성 폐결핵으로 진단된 전공의에게 노출된 의료종사자들에 대하여 실시한 접촉자 조사의 결과를 보고한다. 방법: 활동성 폐결핵 환자와 밀접한 접촉을 한 사람(접촉자) 101명 중 89명이 접촉자 조사에 응하여 조사를 받았다. 1차 접촉자 조사는 지표환자의 증상 개시 후 30일경에, 2차 조사는 1차 조사 10주 후에 기침, 발열, 인후통, 체중 감소와 같은 임상증상 확인 및 단순흉부촬영과 함께 결핵반응검사(Tuberculin skin test, TST)/QuantiFERON-TB Gold (QFT-G) 2단계 검사법을 시행하였다. 결과: 1차 TST 양성자는 34명(38.2%)이었고, TST 양성자 중 35세 이하 접촉자에서 시행한 QFT-G 양성률은 37.5% (6/16)이었다. 1차 TST 음성 대상자 41명에게서 시행한 2차 TST에서 17명(41.5%)이 양전을 보였고 그들 중 시행한 QFT-G 검사에서 3명(17.6%)이 양성이었다. 활동성 결핵으로 진단된 접촉자는 없었으며 지표환자에 노출되어 발생한 결핵 전파율은 2단계 검사법으로는 7.3% (3/41)였고, TST 진단법으로는 41.5% (17/41)였다. 결론: 국내에서 처음 보고되는 병원 내 결핵 접촉자 조사 연구로서 LTBI 발생률이 그 진단 기법에 따라 달랐으며 따라서 앞으로 발생할 수 있는 의료종사자들에 대한 병원 내 결핵 접촉자 조사를 위해 조직적이고 실용적인 가이드라인이 필요할 것이다.

• 보건세계
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• 제63권1호
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• pp.5-7
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• 2014

우리나라 인구의 약 1/3이 결핵에 감염된 것으로 알려져 있다. 많은 사람들이 이 대목에서 깜짝 놀란다. '국민 3명 중 1명이 감염자라고?' 감염이 곧 '결핵'을 의미하는 것은 아니다. 하지만 감염이 된 사람은 언제든 결핵으로 진전될 가능성을 안고 있는, 잠재적 결핵환자이다. 이 페이지에서는 내 몸에 결핵균이 들어왔는지 여부를 확인 할 수 있는 TST, 즉 투베르쿨린 피부검사에 대해 알아보기로 한다.

• Tuberculosis and Respiratory Diseases
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• 제72권2호
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• pp.140-148
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• 2012

Background: Detection and treatment of tuberculosis (TB) infection with contact investigation is a key component of TB control program. I evaluated the prevalence and risk factors for TB infection among contacts of recently diagnosed pulmonary TB patients in a tertiary hospital in Korea. Methods: 206 contacts of 90 adult pulmonary TB patients underwent tuberculin skin tests (TST) and chest radiography. The TST results were considered positive with an induration of 10 mm or more, suggesting TB infection. A standardized questionnaire was used to assess risk factors associated with TB infection. Results: TST was positive in 97 of 206 contacts of TB patients (47.1%) and positive rate of TST increased with age. The risk of TB infection was significantly associated with close contact with TB patients (sleeping in the same room) (odd ratio [OR], 4.94; 95% confidence interval [CI], 1.43~17.00). Conclusion: TB infection rate was higher in the elderly, and the risk of TB infection was significantly increased with close contact of TB patients.

• Tuberculosis and Respiratory Diseases
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• 제78권4호
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• pp.349-355
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• 2015

Background: The tuberculin skin test (TST) is the standard tool to diagnose latent tuberculosis infection (LTBI) in mass screening. The aim of this study is to find an optimal cut-off point of the TST+ rate within tuberculosis (TB) contacts to predict the active TB development among adolescents in school TB outbreaks. Methods: The Korean National Health Insurance Review and Assessment database was used to identify active TB development in relation to the initial TST (cut-off, 10 mm). The 7,475 contacts in 89 schools were divided into two groups: Incident TB group (43 schools) and no incident TB group (46 schools). LTBI treatment was initiated in 607 of the 1,761 TST+ contacts. The association with active TB progression was examined at different cut-off points of the TST+ rate. Results: The mean duration of follow-up was $3.9{\pm}0.9years$. Thirty-three contacts developed active TB during the 4,504 person-years among the TST+ contacts without LTBI treatment (n=1,154). The average TST+ rate for the incident TB group (n=43) and no incident TB group (n=46) were 31.0% and 15.5%, respectively. The TST+ rate per group was related with TB progression (odds ratio [OR], 1.025; 95% confidence interval [CI], 1.001-1.050; p=0.037). Based on the TST+ rate per group, active TB was best predicted at TST+ ${\geq}$ 16% (OR, 3.11; 95% CI, 1.29-7.51; area under curve, 0.64). Conclusion: Sixteen percent of the TST+ rate per group within the same grade students can be suggested as an optimal cut-off to predict active TB development in middle and high schools TB outbreaks.

• The Korean journal of internal medicine
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• 제33권6호
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• pp.1241-1251
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• 2018

Background/Aims: To estimate the level of agreement and positivity rates of latent tuberculosis infection (LTBI) tests prior to the use of tumor necrosis factor (TNF) inhibitors in relation to underlying rheumatic diseases and endemic tuberculosis levels. Methods: The Ovid-Medline, Embase, and Cochrane Libraries were searched for articles before October 2013 involving LTBI screening in rheumatic patients, including rheumatoid arthritis (RA), ankylosing spondylitis (AS), juvenile idiopathic arthritis (JIA), and psoriatic arthritis. Results: In pooled analyses, 5,224 rheumatic patients had undergone both a tuberculin skin test (TST) and an interferon-gamma release assay (IGRA) before TNF inhibitors use. The positivity of TST, QuantiFERON-TB Gold In Tube (QFT-GIT), and T-SPOT.TB (T-SPOT) tests were estimated to be 29%, 17%, and 18%, respectively. The agreement percentage between the TST and QFT-GIT, and between the TST and T-SPOT were 73% and 75%. Populations from low-to-moderate endemic TB presented with slightly less agreement (71% between TST and QFT-GIT, and 74% between TST and T-SPOT) than patients from high endemic countries (73% between TST and QFT-GIT, and 81% between TST and T-SPOT). By underlying disease stratification, a lower level of agreement between TST and QFT-GIT was found among AS (64%) than among JIA (77%) and RA patients (73%). Conclusions: We reaffirm the current evidence for accuracy of LTBI test done by TST and IGRA among rheumatic patients is inconsistent. Our stratified analysis suggests different screening strategies might be needed in clinical settings considering the endemic status in the patient's country of origin and the precise nature of underlying diseases.

• Journal of Preventive Medicine and Public Health
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• 제52권4호
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• pp.272-275
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• 2019

The 2018 National Guideline for Tuberculosis Control, which was published by the Korea Centers for Diseases Prevention and Control (KCDC), mandates conducting an epidemiological survey among close contacts of active tuberculosis patients at public institutions such as schools. In the procedure for these surveys, the tuberculin skin test (TST) is mandated as the screening test for latent tuberculosis infection in elementary school students. However, several guidelines recommend using the interferon-gamma releasing assay (IGRA) for contacts aged over 5 years with a Bacillus Calmette-$Gu{\acute{e}}rin$ vaccination history. The main reason for this is that IGRA has a higher specificity and lower false positive rate than TST. In addition, IGRA requires only a single visit to draw blood and the results are available within 24 hours. These advantages could promote cooperation from both parents and students in conducting these surveys. Thus, these findings regarding the benefits of IGRA for surveys of close contacts at elementary schools should be incorporated into the KCDC guideline.

• Tuberculosis and Respiratory Diseases
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• 제68권3호
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• pp.155-161
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• 2010

Background: The tuberculin skin test (TST) has limitations in diagnosing a latent tuberculosis infection (LTBI). The interferon-gamma release assay (IGRA) was introduced to middle- and high-school students since 2009 by the Korea Centers for Disease Control and Prevention. The aim was to evaluate the utility of IGRA in diagnosing LTBI in middle- and high-school students. Methods: From August 2007 to July 2009, among suspected LTBI students showing TST induration with a 10 mm diameter and over with a normal chest x-ray in school students of Jeju city, 341 students underwent a Quanti FERON-TB Gold In-Tube (QFT-IT) test to confirm LTBI. Results: From 348 students showing a positive TST, a QFT-IT test was carried out on 341 students. The positive QFT-IT rate was 52.8% (=180/341). The positive QFT-IT rate was higher in high-school boys with a 15~19 mm diameter of induration in TST. Conclusion: With the introduction of IGRA for diagnosing LTBI in middle- and high-school students, approximately 47% of students who show a TST induration with a 10 mm diameter and over can avoid taking unnecessary preventive chemotherapy. These results suggest that IGRA is useful for diagnosing and controlling LTBI in Korean students.