The Effectiveness of Chest Radiographic Screening Among Tuberculosis Contacts

Yu-Hsun Huang, Pei-Chun Chan, Min-Ju Lu, Yun-Tsan Liao, Chien-Ban Hsu, Chang-Hsun Chen

2015 Vol.31 NO.6

Correspondence Author: Yu-Hsun Huang

  • Division of HIV/AIDS and TB, Centers for Disease Control, Ministry of Health and Welfare, Taiwan


For decades, the most important strategy in tuberculosis (TB) control in Taiwan is to find case early and provide treatment to patient in a timely manner. In order to detect a case in a timely way, finding active TB cases amongst populations with poor access to medical care has been found to be especially important. Due to the implementation of various strategies, the number of infectious TB patients in Taiwan has decreased yearly, in a gradual fashion. The strategy of active case finding (ACF) has been adjusted step by step. Review from literature, an enhanced ACF effort for a TB contact is the best way to decrease the persistent transmission of TB from both an empirical and cost-benefit point of view. Our study enrolled the contacts of TB patients diagnosed from April 1, 2008 to December 31, 2012. Every contact had at least completed an initial chest radiograph (CXR) for the purpose of contact tracing. The rate of newly developed TB among contacts was further analyzed with stratifications of infectious TB index patients and birth cohorts of contacts. The effectiveness of both first and 12th month CXR screening was evaluated respectively. The results showed that the first CXR screening among contacts was helpful for ACF. The detection rate of TB after the first CXR performed on the contacts, whose index TB patient had extra-pulmonary TB without lung involvement, was found to be low enough that CXR service could be suspended for this target population if radiographic resources were strained at some point in the future. However, contact screening for target population younger than 5 years was still essential. As to the 12th month CXR among contacts, the detection rate was acceptable only when index TB patients were smear-positive and culture confirmed as Mycobacterium tuberculosis. For contacts whose index TB patients were classified as infectious, those who took 12th month CXR examination could be diagnosed 2 months earlier compared with those who did not complete 12th month CXR examination. 

Keywords:effectiveness of chest radiograph;TB contacts;active case finding