The Guidelines Group discussed the GRADE

The Guidelines Group discussed the GRADE
assessment of the evidence on the use of
IGRA as a screening tool to identify patients
with latent TB infection (Annex 9). Two types of IGRA
were considered: Quantiferon Gold in tube assay
and T-Spot assay. Two studies considered the ability
of IGRA to predict development of TB over time.
[32,33] Eight studies evaluated the performance of
Quantiferon Gold in tube assay among HIV-infected
adults with confirmed TB, and one study evaluated its
sensitivity among children living with HIV diagnosed
with TB. Similarly, five studies reported the sensitivity
of a T-Spot assay among adults living with HIV and
TB, and two studies reported its sensitivity among
children living with HIV with confirmed TB.
However, IGRA cannot generally distinguish
between active TB disease and latent infection
[34] and their performance is compromised among
people living with HIV compared to those without
HIV. Significantly higher rates of indeterminate test
results were found with Quantiferon gold in tube test
in persons with HIV compared to persons without
HIV, and in persons with low CD4 cell counts
compared to persons with higher CD4 cell counts.
Its sensitivity was also markedly reduced among
patients with low CD4 counts. Similarly, while most
studies found no impact of low CD4 cell count on the
sensitivity of T-Spot assay, at least one study found
that sensitivity was significantly reduced among
patients with low CD4 counts.