Interferon gamma release assays and tubercolin skin test performance in different settings of HIV immunodeficiency.

ABSTRACT

BACKGROUND/AIM: HIV infection is a risk factor for re-activation of latent tubercolosis infection (LTBI). In recent years new blood tests for the detection of TB infection have been developed Quantiferon TB Gold in Tube and TSPOT TB, which are interferon-γ releasing assays (IGRAs), have improved the identification of LTBI. In our study we have compared IGRAs and TST in HIV-positive patients with different settings of immunodeficiency. PATIENTS AND METHODS: 98 consecutive HIV patients were recruited. They underwent a blood draw, a chest radiography and a tuberculin skin test. The HIV infection setting was detected and IGRAs were carried-out. Five patients showed a complete correspondence of TST, TSPOT-TB and QFT-IT. Discordant results were observed in patients testing positive to IGRAs but negative to TST. Only 2 patients showed positive TST and negative IGRAs. CONCLUSION: Our study showed a poor concordance between tuberculin skin test and IGRAs, mainly in patients with a low CD4 cell count.