QuantiFERON-TB Gold In-Tube test in active tuberculosis patients and healthy adults

Abstract

Interferon-gamma (IFN-γ) release assays have improved latent tuberculosis (TB) detection and have been considered promising for the diagnosis of TB disease. However, diagnosis efficacy data is limited in high burden countries. The aim of this study was to determine the diagnostic potential of the QuantiFERON-TB Gold In-Tube (QFT-GIT) test for the diagnosis of active TB in an endemic setting for TB. A cross-sectional study was conducted in a group of 102 Thai patients with clinical symptoms and chest x-ray findings suggesting of active pulmonary TB and a group of 112 healthy adults. Testing was carried out using sputum microscopy, mycobacterial culture and QFT-GIT test. Of these patients, QFT-GIT was positive in 73 (71.57%), negative in 27 (26.47%), and undetermined in 2 (1.96%) cases. Among healthy controls, QFT-GIT was positive in 18 (16.07%), negative in 93 (83.04%), and undetermined in 1 (0.89%) person. Based on TB culture results, the sensitivity of QFTGIT for diagnosing active TB was 84.21% (95% confidence interval (CI); 72.13-92.52). The positive and negative predictive values were 65.75% (95% CI; 59.26-71.70) and 66.67% (95% CI; 49.94-80.04), respectively. The median IFN-γ level in culture-confirmed TB patients was 3.91 compared to 0.03 IU/mL of the healthy group. QFT-GIT appears to be a useful indirect test for TB diagnosis in Thailand and its use is recommended in association with clinical and radiological assessments for identifying active or latent TB.

Performance of a lymphocyte t interferon gamma test (Quantiferon-TB gold in tube) in the diagnosis of active tuberculosis in HIV-infected children

“…In the absence of microbiological evidence, in southern countries, the diagnosis is made based on factors such as the notion of exposure, the presence of suggestive symptoms, the demonstration of a specific immune response, and the radiological appearance [2]. Therefore, sensitive tools complementing conventional tests are needed to guide the initiation of therapy when the diagnosis of TB disease remains doubtful [6]. Interferon gamma release assays (IGRAs) are immunodiagnostics tools in which interferon-gamma (IFN-γ) released by T-cells in response to Mycobacterium tuberculosis (M. tuberculosis)-specific antigen is measured [4,[6][7][8].…”

“…Therefore, sensitive tools complementing conventional tests are needed to guide the initiation of therapy when the diagnosis of TB disease remains doubtful [6]. Interferon gamma release assays (IGRAs) are immunodiagnostics tools in which interferon-gamma (IFN-γ) released by T-cells in response to Mycobacterium tuberculosis (M. tuberculosis)-specific antigen is measured [4,[6][7][8]. They are based on in vitro stimulation of T cells using antigens specific for Mycobacterium tuberculosis, which are absent in Bacillus Calmette and Guérin (BCG) and in most atypical mycobacteria.…”

“…The QFT-GIT has been reported to have higher sensitivity, specificity and be more attractive than the tuberculin skin test (TST) [4][5][6][7][9][10][11] which may result in interpretation errors [5,6,11], including the need of two clinic visits. Collecting blood samples may not frequently encounter difficulties compared with other specimens collection and QFT-GIT can provide rapid results, within two days [6]. However, specificity depends on multiple factors in addition to the test antigen, including the cutoffs used to interpret the test and the analytical methods employed to measure IFN-γ concentrations [7].…”

“…Also, it's performance in detecting active or latent tuberculosis infection (LTBI) can vary depending on the tested populations and regions [6]. Numerous studies have assessed the utility of the QFT-GIT in diagnosing latent TB infection (LTBI) in various clinical settings [6]. Regarding active TB, the use of IGRAs has been unclear particularly in HIV-infected children in high prevalence settings [4,6,[12][13][14][15][16].…”

Interferon‐Gamma test for the detection of Mycobacterium tuberculosis complex infection in Macaca mulatta and other non‐human primates

“…In 2018, repeatedly skin test‐negative but MTB complex‐infected animals were found in an established cynomolgus macaque colony . Alternative in vitro interferon‐gamma (IFNy) release assays (IGRA) are now used widely in humans and cattle . A similar IGRA for non‐human primates was discontinued by its manufacturer in 2015, leaving no readily available alternative or adjunct to TST for monitoring specific cell‐mediated immunity to MTB infection.…”