VIDAS® TB-IGRA assay for diagnosing tuberculosis infection in people living with HIV: A preliminary study

Background The diagnosis of presumed latent tuberculosis (TB) infection (LTBI) is problematic in people living with HIV (PLWH) because of sub-optimal sensitivity and high indeterminate rates, especially in those with advanced immunosuppression. Better diagnostic tools for LTBI are needed in this sub-population. Methods We compared the sensitivity of VIDAS TB-IGRA, a fully automated RD1-specific new interferon-ϒ-release assay (IGRA), to QFT-Plus in 77 PLWH with active pulmonary TB who had varying CD4 counts. Sputum culture positivity served as the reference standard for active TB. Results The sensitivity of VIDAS TB-IGRA was similar to QFT-Plus overall [90.9% (70/77) vs 92.0% (69/75)], in those with CD4 3 , [88.9% (40/45) vs 88.6% (39/44)], and in those with CD4 Conclusion VIDAS TB-IGRA had a similar sensitivity to QFT-Plus in PLWH. Whether VIDAS TB-IGRA sensitivity is significantly better at lower CD4 counts remains to be confirmed in a larger study. These data have implications for the diagnosis of LTBI in those with advanced immunosuppression.