Comparison of the 2-step tuberculin skin test and QuantiFERON-TB Gold in-Tube test in the screening of latent tuberculosis infection in cancer patients

Abstract

Interferon-γ release assay (IGRA) may improve the diagnostic accuracy for latent tuberculosis infection (LTBI). The aim of this study was to compare the performance of the QuantiFERON-TB Gold-in-Tube (QFT-GIT), with the tuberculin skin test (TST) (one and two step TST) in detection of LTBI in immunocompromised cancer patients.The study was carried out on 50 patients and 20 healthy subjects as a control group. Patients with active TB or AIDS were excluded. A TSTI was only positive in 2 patients (4%). The TSTII (booster phenomena) was positive in 8 patients (16%) after 3–4weeks. Ten patients (20%) had positive Quantiferon test while the test was indeterminate in 14 patients (28%).Hematological malignancy group (HMgroup) had significantly more positive TSTII results followed by the breast cancer group (p=0.01). Similarly, QFT-GIT positive values were significantly more frequent in the HM group. This study suggests that the QFT-GIT test maintains its sensitivity and performance in immunocompromised cancer patients, identifying a large number of truly infected patients being anergy to the tuberculin skin test.