Tuberc Respir Dis.  2012 Oct;73(4):219-223.

Prevalence of Latent Tuberculosis Infection among Medical Students in South Korea

• Jung DH
• Jo KW
• Shim TS

Abstract

BACKGROUND
We investigated the prevalence of latent tuberculosis infection (LTBI) among medical students in South Korea.
METHODS
Students from one medical school, who were in second- or third-year classes before clerkship course, were enrolled for three consecutive years in the study. A standard questionnaire was given to each participant, and tuberculin skin test (TST), QuantiFERON-TB GOLD In-Tube (QFT-GIT) assay, and chest radiography were performed.
RESULTS
A total of 153 participants were enrolled in the study. The mean age of the subjects was 21.9+/-0.9 years, 105 (68.6%) were male, and 132 (86.3%) had been vaccinated with Bacille Calmette-Guerin (BCG). Four students (2.6%) had a history of contact with tuberculosis (TB) patients during medical practice. No abnormal chest radiograph findings were found for any of the subjects. Of the 153 subjects, 23 (15.0%) tested positive for the TST, and 8 (5.2%) tested positive for the QFT-GIT. The agreement between the two tests was determined to be 0.34 using kappa coefficients. Of the four students who had a history of contact with TB patients, only one subject tested positive for both tests, and the other three students tested negative for both tests.
CONCLUSION
A low prevalence of LTBI was found among medical students before clerkship course in South Korea.

Keyword

Latent Tuberculosis; Tuberculin Test; Interferon-gamma Release Tests, Schools, Medical; Students

MeSH Terms

Humans
Latent Tuberculosis
Male
Prevalence
Surveys and Questionnaires
Republic of Korea
Schools, Medical
Skin Tests
Students, Medical
Thorax
Tuberculin
Tuberculin Test
Tuberculosis
Tuberculin

Figure

• 

  Figure 1 Scatter plot of individual responses of the TST and QFT-GIT in medical students. The dashed line represents the cutoff of 0.35 IU/mL for interferon-gamma. All points below zero for QTF-GIT results in this figure have been assigned a value of zero. TST: tuberculin skin test; QFT-GIT: QuantiFERON-TB Gold In-Tube.

Reference

1. Treatment outcomes of tuberculosis patients through Private-Public Mix collaboration [PPM] in private sector in Korea, 2011 [Internet]. 2011. cited 2012 Sep 8. Cheongwon: Korea Centers for Disease Control and Prevention;Available from: http://www.cdc.go.kr/CDC/info/CdcKrInfo0301.jsp?menuIds=HOME001-MNU0001-MNU0036-MNU0037&q_type=A&q_value=2012&cid=12798&pageNum.

2. Kim HJ, Bai GH, Kang MK, Kim SJ, Lee JK, Cho SI, et al. A public-private collaboration model for treatment intervention to improve outcomes in patients with tuberculosis in the private sector. Tuberc Respir Dis. 2009. 66:349–357.

3. Horsburgh CR Jr, Rubin EJ. Clinical practice: latent tuberculosis infection in the United States. N Engl J Med. 2011. 364:1441–1448.

4. Schablon A, Diel R, Diner G, Anske U, Pankow W, Ringshausen FC, et al. Specificity of a whole blood IGRA in German nursing students. BMC Infect Dis. 2011. 11:245.

5. Sokal JE. Editorial: measurement of delayed skin-test responses. N Engl J Med. 1975. 293:501–502.

6. Mori T, Sakatani M, Yamagishi F, Takashima T, Kawabe Y, Nagao K, et al. Specific detection of tuberculosis infection: an interferon-gamma-based assay using new antigens. Am J Respir Crit Care Med. 2004. 170:59–64.

7. Landis JR, Koch GG. The measurement of observer agreement for categorical data. Biometrics. 1977. 33:159–174.

8. Kang YA, Lee HW, Yoon HI, Cho B, Han SK, Shim YS, et al. Discrepancy between the tuberculin skin test and the whole-blood interferon gamma assay for the diagnosis of latent tuberculosis infection in an intermediate tuberculosis-burden country. JAMA. 2005. 293:2756–2761.

9. Lee K, Han MK, Choi HR, Choi CM, Oh YM, Lee SD, et al. Annual incidence of latent tuberculosis infection among newly employed nurses at a tertiary care university hospital. Infect Control Hosp Epidemiol. 2009. 30:1218–1222.

10. Choi CM, Kang CI, Kim DH, Kim CH, Kim HJ, Lee CH, et al. The role of TST in the diagnosis of latent tuberculosis infection among military personnel in South Korea. Int J Tuberc Lung Dis. 2006. 10:1342–1346.

11. Brock I, Weldingh K, Lillebaek T, Follmann F, Andersen P. Comparison of tuberculin skin test and new specific blood test in tuberculosis contacts. Am J Respir Crit Care Med. 2004. 170:65–69.

12. Choi JC, Shin JW, Kim JY, Park IW, Choi BW, Lee MK. The effect of previous tuberculin skin test on the follow-up examination of whole-blood interferon-gamma assay in the screening for latent tuberculosis infection. Chest. 2008. 133:1415–1420.

13. Lee KJ, Kang YA, Kim YM, Cho SN, Moon JW, Park MS, et al. Screening for latent tuberculosis infection in South Korean healthcare workers using a tuberculin skin test and whole blood interferon-gamma assay. Scand J Infect Dis. 2010. 42:672–678.

14. Huang YW, Shen GH, Lee JJ, Yang WT. Latent tuberculosis infection among close contacts of multidrug-resistant tuberculosis patients in central Taiwan. Int J Tuberc Lung Dis. 2010. 14:1430–1435.

15. Shalabi NM, Houssen ME. Discrepancy between the tuberculin skin test and the levels of serum interferon-gamma in the diagnosis of tubercular infection in contacts. Clin Biochem. 2009. 42:1596–1601.

16. Wang L, Turner MO, Elwood RK, Schulzer M, FitzGerald JM. A meta-analysis of the effect of Bacille Calmette Guérin vaccination on tuberculin skin test measurements. Thorax. 2002. 57:804–809.

17. Demangel C, Brodin P, Cockle PJ, Brosch R, Majlessi L, Leclerc C, et al. Cell envelope protein PPE68 contributes to Mycobacterium tuberculosis RD1 immunogenicity independently of a 10-kilodalton culture filtrate protein and ESAT-6. Infect Immun. 2004. 72:2170–2176.

18. Liu XQ, Dosanjh D, Varia H, Ewer K, Cockle P, Pasvol G, et al. Evaluation of T-cell responses to novel RD1-and RD2-encoded Mycobacterium tuberculosis gene products for specific detection of human tuberculosis infection. Infect Immun. 2004. 72:2574–2581.

19. Lew WJ, Jung YJ, Song JW, Jang YM, Kim HJ, Oh YM, et al. Combined use of QuantiFERON-TB Gold assay and chest computed tomography in a tuberculosis outbreak. Int J Tuberc Lung Dis. 2009. 13:633–639.

20. van Zyl-Smit RN, Pai M, Peprah K, Meldau R, Kieck J, Juritz J, et al. Within-subject variability and boosting of T-cell interferon-gamma responses after tuberculin skin testing. Am J Respir Crit Care Med. 2009. 180:49–58.