Contribution of Interferon gamma release assays testing to the diagnosis of latent tuberculosis infection in HIV-infected patients: A comparison of QuantiFERON-TB Gold In Tube, T-SPOT.TB and tuberculin skin test

Abstract

BackgroundDiagnosis and treatment of latent tuberculosis infection (LTBI) is the most effective strategy to control tuberculosis (TB) among patients with HIV infection. The tuberculin skin test (TST) was the only available method to identify LTBI. The aim of the present work was to evaluate the usefulness of the interferon-gamma release assays (IGRAs): QuantiFERON-tuberculosis (TB) Gold-In-Tube test (QFG) and T-SPOT.TB for the diagnosis of LTBI in a diverse cohort of HIV-infected patients.MethodsA prospective study was carried out in consecutive patients cared for in a single institution in Spain from January 2009 to October 2010. IGRAs and TST were performed simultaneously. TST induration ≥ 5 mm was considered positive.ResultsQFG, T-SPOT.TB and TST were performed in 373 subjects. Median CD4 cell count was 470/μl with a median nadir of 150/μl. TST, QFG and T-SPOT.TB were positive in 13.3%, 7.5% and 18.5% cases respectively. Among 277 patients with neither past or current TB nor previous treatment for LTBI and who had TST results, a positive TST result was obtained in 20 (7.2%) cases. When adding QFG results to TST, there were a total of 26 (8.6%) diagnoses of LTBI. When the results of both IGRAs were added, the number of diagnoses increased to 54 (17.9%) (incremental difference: 10.7% [95% confidence interval [CI]:5.3-16.2%] [p < 0.001]), and when both IGRAs were added, the number of diagnoses reached 56 (18.5%) (incremental difference: 11.3% [95% CI:5.7%–16.9%] [p < 0.001]). Patients with a CD4 cell count greater than 500 cells/μl and prior stay in prison were more likely to have a diagnosis of LTBI by TST and/or QFG and/or T-SPOT.TB (adjusted odds ratio [aOR]: 3.8; 95% CI, 1.4 – 9.9; and aOR: 3.3; 95% CI, 1.3 – 8.3, respectively).ConclusionsIGRAs were more sensitive than TST for diagnosis of M. tuberculosis infection in HIV-infected patients. Dual sequential testing with TST and IGRAs may be the optimal approach for LTBI screening in this population.

Utility of QuantiFERON-TB Gold In-Tube Test in the Diagnosis of Latent TB in HIV-Positive Patients in a Medium-TB Burden Country

“…Although some parameters have been shown to affect the results, studies evaluating these tests face a challenge, which is the lack of a ''gold standard'' for assessing their sensitivity and specificity, particularly in HIV-infected patients. 8,12 Positive TST results (24.6%) in our study were lower than similar reports of TB-high endemic settings (46.5%) and higher than TB-low endemic settings (7.7%). 19 Positive QFT in our study was 7.7%, which was lower than the reported value for a highly endemic TB setting (68%) and higher than the result (5.3%) of low endemic setting.…”

Correlación de la respuesta a antígenos de Mycobacterium tuberculosis y la prueba cutánea tuberculina en pacientes con artritis reumatoide

“…The TST has traditionally been used to detect LTBI; however, it is not a very specific diagnostic tool (28,29). This may be explained by the possible effects of BCG vaccination (30)(31)(32) and the presence of environmental mycobacteria (33), which can increase the incidence of false-positive results in countries such as Colombia, where vaccination is widely and routinely performed.…”

Challenges in planning and conducting diagnostic studies with molecular biomarkers

“…qFigure 5 illustrates this phenomenon based on the previously published data by Ramos et al [55]. Here, the value of the interferon gamma release assay (IGRA) for the diagnosis of tuberculosis was examined.…”