Combined use of QuantiFERON-TB Gold assay and chest computed tomography in a tuberculosis outbreak

Int J Tuberc Lung Dis. 2009 May;13(5):633-9.


Objective: To evaluate the value of the QuantiFERON-TB Gold (QFT-G) assay and chest computed tomography (CT), in addition to the conventional use of the tuberculin skin test (TST) and chest radiography (CXR), in a contact investigation of a tuberculosis (TB) outbreak.

Design: In a contact investigation of a TB outbreak in a high school, TST and CXR were performed on all 1044 employees and students. QFT-G was performed on TST-positive subjects, and CT on QFT-G-positive subjects and students with TST > or =20 mm.

Results: TST was positive in 388 subjects (37.2%), while QFT-G was positive in 7.6% (30/394). CXR showed abnormal findings suggestive of TB in 10 (1.0%) subjects, all of whom were TST-positive and six of whom were QFT-G-positive. Findings suggestive of active TB were noted in 17 (32.7%) of 52 subjects by CT. Collectively, among 21 (1.1%) TB patients, all were TST-positive, 12 (57.1%) were QFT-G-positive and active TB was diagnosed by CT, and not by CXR, in 11 subjects.

Conclusion: Compared to the conventional approach, the additional use of QFT-G in TST-positive subjects and chest CT in subgroups with a high probability of infection was found to be more effective in the differentiation between active TB, latent TB and non-infected subjects in a contact investigation.

Publication types

  • Comparative Study

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Diagnosis, Differential
  • Disease Outbreaks / statistics & numerical data*
  • Female
  • Humans
  • Korea / epidemiology
  • Male
  • Mass Screening / methods
  • Middle Aged
  • Radiography, Thoracic / methods*
  • Retrospective Studies
  • Tomography, X-Ray Computed / methods*
  • Tuberculin Test / methods*
  • Tuberculin*
  • Tuberculosis, Pulmonary / diagnosis*
  • Tuberculosis, Pulmonary / epidemiology*
  • Young Adult


  • Tuberculin