| Interferon-gamma Release Assay among Tuberculin Skin Test Positive Students in Korean High Schools. |
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Young Kil Park, Seung Heon Lee, Su Young Kim, Sung Weon Ryoo, Chang Ki Kim, Hee Jin Kim, Eun Hee Cho, Byung Hee Yoo, Jong Koo Lee, Won Jung Ko |
1Department of Microbiology, Korean Institute of Tuberculosis, Seoul, Korea. ypark7@empal.com
2Division of HIV and Tuberculosis Control, Center for Disease Control, Korea Centers for Disease Control & Prevention, Seoul, Korea.
3Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea. |
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| Abstract |
BACKGROUND
There are several active tuberculosis (TB) cases in Korean high schools each school year. The risk of transmission in schools is extremely high due to the considerable time spent in closed classrooms. We evaluated the control of latent tuberculosis infection in Korean high schools. METHODS: When a student was identified with active TB, tuberculin skin testing was performed on their classmates and on students in their same school grade. When a student had a positive tuberculin skin tests (TST), they underwent follow-up testing with QuantiFERON-TB Gold In-Tube (QFT). The manufacturer recommended a cut-off of 0.35 IU/mL to determine QFT positivity was applied. RESULTS: A total of 131 pulmonary tuberculosis (TB) patients were included based on the criteria for screening TB contacts in the National Tuberculosis Control Program. Seventy-five (57.2%) students tested smear positive. TST were performed on 7,109 students who were classmates of, or in the same grade as, a TB patient. Of the contacts, 1,231 students (17.3%) were TST positive and they were screened with QFT. Six hundred-sixty-six (55.0%) of the tested students returned a positive QFT result and the rate of positivity was significantly associated with the increasing size of TST indurations (p<0.0001). CONCLUSION: The use of QFT resulted in approximately 45% of TST positive students not being given chemoprophylaxis. |
| Key Words:
Interferon-gamma Release Assay, Latent Tuberculosis Infection, Tuberculin Test, Students |
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