[Quantiferon-TB Gold In-Tube test in the diagnosis of pulmonary and extra-pulmonary tuberculosis]

Abstract

Introduction: The Interferon-γ in vitro detection tests could be a useful tool in the diagnosis of active tuberculosis compared to Mycobacterium tuberculosis (MTB).

Methods: The QuantiFERON-TB-Gold in Tube (QFG-IT) test was performed on the blood of 118 patients with active tuberculosis and the results compared with the tuberculin test.

Results: The QFG-IT test was positive in 94 cases (79.7%), negative in 17 (14.4%) and indeterminate in 7 (5.9%). A negative or indeterminate QFG-IT test was more common in older patients (P=0.017) and in cases with negative smear tests (P=0.041). The kappa agreement between the tuberculin and QFG-IT tests was 74.5% with a kappa value of 0.45 (SE:0.136). Thirteen of the patients studied were infected with HIV and the tuberculin was positive in 5 of the 12 cases (38.5%) in whom it was performed, with the QFG-IT being positive in 9/13 (69.2%).

Conclusions: The QFG-IT test may be a useful complimentary tool to the tuberculin test in the diagnosis of tuberculosis.