Abstract
Introduction: Tuberculin-skin-test(TST) has been the only method for diagnosis of tuberculosis (TB) infection until detection of interferon-gamma by QuantiFERON-TB Gold in tube (QFN-G-IT) and T-SPOT.TB have been introduced. (IGRAs).
Aims:To assess the correlation between TST and IGRAs with risks factors for TB infection in smear positive(S+) pulmonary TB-contacts.
Material and methods:Contacts with S+pulmonary TB cases were underwent TST, chest radiography, sputum analysis, QFN-G-GIT and T-SPOT.TB and investigated HIV, immunosuppression, BCG-vaccination, degree of contact (≥ or <6h/day). In index case was studied presence of cough, diagnostic delay, contact conditions: room size(square meters) and index of overcrowding(square meters/person).
Results:156 contacts(119 adults, 37 children) of 66 patients completed the study. Positivity of TST did not correlated with any of the risk factors studied: cough(p = 0.929), diagnostic delay(p = 0.244), room size (0.462), overcrowding(0. 800). QFN-G-IT was associated with cough(p = 0.001) and room size(p = 0.020) while T-SPOT.TB was also associated with cough(p = 0.007) and room size(p = 0.023). Association with diagnostic delay tended to significance (p = 0.077).
Conclusions:The results obtained suggest that IGRAs correlated better than TST with some risk factors involved in the transmission of TB. Larger studies are needed to confirm this findings.
- © 2013 ERS