• Health Policy and Management
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• v.23 no.4
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• pp.349-357
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• 2013

Background: Although interferon-gamma release assay (IGRA) is now available alternatives to tuberculin skin test (TST) for detection of latent tuberculosis infection (LTBI), the cost of IGRA test is much higher than TST. So economic analysis of LTBI screening strategies have been done in many countries, but there are few reports in Korea. This study examined cost analysis of LTBI screening strategies in Korea. Methods: The economic outcomes were evaluated by five strategies. These were 1) TST alone, 2) IGRA alone, 3) combination of TST and IGRA (TST followed by IGRA) and 4) no testing no prevention, 5) no testing all prevention. Last two strategies were added to compare with three main LTBI screening strategies. Decision analysis model were used to perform economic analysis. A cohort study of Korean Institute of Tuberculosis and the data of published literatures were used to estimate the cost analysis. Results: In a base-case scenario which was assumed that TST specificity was 80%, TST alone was the least expensive strategy. In a alternative scenario which was assumed that TST specificity was 97%, the combination of TST and IGRA was the least expensive strategy. Sensitivity analysis shows that patients adherent rate to LTBI treatment, TST sensitivity, IGRA sensitivity and IGRA specificity did not have a significant impact on the outcomes. Conclusion: In Korea, for the diagnosis of LTBI at the time of child and adolescent, TST alone reduces medical costs compared with IGRA alone or combination of TST and IGRA.

• 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.

• Korean Journal of Clinical Laboratory Science
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• v.48 no.3
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• pp.225-229
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• 2016

Tuberculosis (TB) is caused by a chronic infectious agent known as Mycobacterium tuberculosis. It is transmitted in airborne particles, called droplet nuclei which was generated by cough, sneeze, shout, or sing of persons who have TB disease. Most infections of TB do not have symptoms, well known as latent tuberculosis infection (LTBI). However, about 10% of LTBI progress to active disease a one or two years after infection. To investigate the LTBI rate of college students who were in contacted with TB patients, we performed chest X-ray, tuberculin skin test (TST) and Interferon-gamma release assay (IGRA) to 74 college students. At a results, 65 students were showed negative and 9 students positive results at chest X-ray and 1st TST test. When confirmed the 65 students who were showed negative by 2st TST, the results showed correctly. But, 9 students who were showed positive results on chest X-ray and 1st TST by IGRA, the only 3 students (4.05%) showed positive results. In conclusion, the LTBI rate in this study showed 4.05% (3/74) and we suggest to investigate other students LTBI rate for decreasing tuberculosis.

• The Korean journal of internal medicine
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• v.33 no.6
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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.

• Korean Journal of Clinical Laboratory Science
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• v.48 no.3
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• pp.202-209
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• 2016

This study is aimed to determine the correlation between the toxin gene types and antibiotic resistance from MRSA (methicillin-resistant Staphylococcus aureus). Fifty-two strains of MRSA, between January 2014, and December 2014, were isolated from clinical specimens obtained from 2,664 cases in the intensive care unit of a hospital in Suncheon, Jeonnam, Korea. Genes encoding mecA, enterotoxin (SE), toxic shock syndrome toxin-1 (TSST-1), exfoliative toxin (ET), and Panton-Valentine leukocidin (PVL) were detected by multiplex PCR-mediated amplification using specific primers. Toxin genes (seg and sei) were present in 40 strains (76.9%), followed by tst in 34 strains (65.4%). Other genes (eta, etb, sea, sed, see, seh, sej, and pvl) were not detected. Forty strains (76.9%) of MRSA had 2 or more toxin genes simultaneously; 5 coexistent toxin-genes (seb, sec, seg, sei, tst) were the most common in 28 strains (53.8%), and 6 strains (11.5%) had seg and sei genes. The coexistence of genes were 72.5~100%, showing a high correlation among genes (seb, sec, seg, sei and tst). As strains (seb, sec, tst) that had particular toxin genes (seb, sec, seg, sei, tst) in multiple showed 100% resistance to ciprofloxacin, clindamycin, erythromycin, we were able to find that seb, sec, and tst genes have a close relationship to the aforementioned antibiotics. It showed a higher resistance to ciprofloxacin, clindamycin, erythromycin, and tetracycline compared with strains that had toxin genes independent from multiple toxin genes.

• Anxiety and mood
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• v.8 no.2
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• pp.146-152
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• 2012

Objective : Individuals with anxiety disorders experience a wide range of time to seeking treatment (TST) as well as various comorbid mental disorders. The present study examined the TST in social anxiety disorder (SAD) and panic disorder. This study aimed to find out the influence of comorbid mental disorder on TST of anxiety disorder through the comparison of SAD and panic disorder. Methods : This study included 311 SAD and 378 panic disorder patients at the initial visit of psychiatric clinic. Contribution of clinical (number of comorbidity, comorbid type and onset age) and demographic (current age) factors to TST were investigated by multivariate analysis. Results : The median length of TST was 14.03 years in SAD and 2.26 years in panic disorder. In social anxiety disorder, fewer comorbidity, younger onset age, and older age were factors associated with delayed TST. In panic disorder, only younger onset age was associated with delayed TST. In both disorders, comorbid depressive disorder was associated with shorter TST. Conclusion : Our data provided the differences in illness behavior needing help based on comorbid mental disorders between SAD and panic disorder. In addition to comorbid disorder, factors affecting TST of anxiety disorder requires future investigation.

• BMB Reports
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• v.49 no.11
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• pp.635-640
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• 2016

Recent evidence indicates that the ephrin receptors and ephrin ligands (Eph/ephrin) expression modulate axonal reorganization and synaptic plasticity in stroke recovery. To investigate the effect of task-specific training (TST) on Eph/ephrin expression in the corticospinal tract (CST) after stroke, we compared Eph/ephrin expression in the peri-infarct cortex, pyramid, and spinal cord of a photothrombotic stroke model of rat brains treated with or without TST. The TST treatment showed significantly better recovery in the behavioral tests compared with no treatment. The significant upregulation of ephrin-A1 and ephrin-A5 observed in activated astrocytes of the CST at 2 weeks' post-stroke was decreased by TST. At 5 weeks, post-stroke, the elevated ephrin-A5 levels were decreased in the ipsilateral pyramid and spinal cord by TST. Glial fibrillary acidic protein was upregulated concomitantly with the altered ephrin expression after stroke, and the expression of these proteins was attenuated by TST. These data suggest that TST alters the expression of ephrin ligands in the CST after stroke.

• Pediatric Infection and Vaccine
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• v.23 no.2
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• pp.94-101
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• 2016

Purpose: This study aimed to describe the results of a contact investigation on health care workers after exposure to a house officer with smear-positive pulmonary tuberculosis (TB). Methods: Eighty nine out of 101 subjects who had close contact with the index patient agreed to be enrolled in the investigation. The first contact investigation was conducted approximately 30 days after the index patient's onset of symptoms, followed by the second investigation after 10 weeks. In both, clinical manifestations were studied, and chest X-ray and tuberculin skin test (TST)/QuantiFERON-TB Gold (QFT-G) in dual screening strategy were conducted. Results: The first TST resulted in positive in 34 subjects (38.2%). QFT-G was conducted on 16 subjects who tested positive in the first TST and aged under 36. Six of them (37.5%) were positive. The second TST was conducted on 41 subjects with negative results in the first TST. Seventeen (41.5%) were positive and among them, three (17.6%) showed positive QFT-G. None of the subjects were diagnosed with active TB. The probability of TB infection through contact with the index patient was 7.3% (3/41) in dual screening strategy while it was 41.5% (17/41) in TST strategy. Conclusions: This first hospital-setting contact investigation for tuberculosis in Korea revealed that latent tuberculosis infection (LTBI) rates vary depending on different diagnostic strategies. This indicates the need for systematic guidelines for diagnosing LTBI in health care workers who have professional exposure to TB.

• Pediatric Infection and Vaccine
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• v.23 no.1
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• pp.18-24
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• 2016

Purpose: There is a the great diagnostic challenge in pediatric tuberculosis especially in high burden setting. The purpose of this preliminary study is to evaluate the agreement between tuberculin skin test (TST) and interferon-gamma release assay (IGRA) including T-SPOT$^{(R)}$.TB and QuantiFERON$^{(R)}$-TB Gold (QFT-G) in Korean children. Method: This retrospective study included children and adolescents who visited to Asan Medical Center to evaluate tuberculosis infection using at least two assays of TST, T-SPOT.TB and QFT-G, from January 2014 to April 2015. Results: A total of 20 patients were included, whose median age was 13.3 years (range, 3.8-18.1 years), and all of them had history of BCG vaccination. Eleven patients had underlying diseases including 7 patients with immunosuppressant medication. The concordance rate between T-SPOT.TB and QFT-G was 90%. However, the concordance rate between TST and T-SPOT.TB was 50%, and between TST and QFT-G was 42.9%. Specificity for the diagnosis of tuberculosis infection of T-SPOT.TB, QFT-G, and TST was 93.3%, 86.7%, and 58.3%, respectively. Conclusions: Although there was a discrepancy between TST and IGRA to diagnose tuberculosis, agreement between T-SPOT.TB and QFT-G was relatively high. Further prospective study to validate the clinical usefulness of each assay for immunologic evidence of tuberculosis infection in Korean children will be mandatory.

• Pediatric Infection and Vaccine
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• v.15 no.1
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• pp.52-58
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• 2008

Purpose : Whole blood interferon-$\gamma$ assay was developed and many studies showed its usefulness in diagnosing tuberculosis (TB) including latent tuberculosis infection (LTBI). However, assessment in children has been limited. This study was undertaken to evaluate the usefulness of QuantiFERON-TB Gold for the diagnosis of LTBI in children exposed to pulmonary TB. Methods : Children who visited Seoul National University Bundang Hospital with a history of TB exposure were enrolled from January 2006 to December 2007. They were evaluated with chest x-rays, tuberculin skin test (TST) and QuantiFERON-TB Gold test. TST was retested 3 months later for those with initial negative reactivity. Definition of LTBI was made on the basis of the TST reactivity. Results : Among the 103 children with a history of TB exposure, 49 children were tested with chest x-ray, TST, and QuantiFERON-TB Gold. Twenty-two were males. Median age was 7.5 years (range; 3 months to 14.7 years). According to TST reactivity, LTBI was in 8 (19%), no infection was in 21 (50%), possible LTBI was in 13 (31%). QuantiFERON-TB Gold test was positive in 5 of the 49 subjects (10%); 3 of the 13 subjects (23.1%) in unknown status, 1 of the 8 subjects (13%) in LTBI, and 1 of the 21 subjects (5%) without infection. The agreement between the QuantiFERON-TB Gold and the TST was poor (${\kappa}=0.101$). Conclusion : QuantiFERON-TB Gold showed poor sensitivity for the diagnosis of LTBI in children with exposure to TB. QuantiFERON-TB Gold alone does not seem to be useful in the diagnosis of LTBI in children.