However, the sensitivity and specificity of this assay has been shown to be suboptimal, leading the World Health Organization (WHO) to limit its use to a subset of HIV-infected adults, adolescents, and children (CD4+ T-cell counts ≤200 cells/μL, or seriously ill regardless of CD4+ T-cell count, or have signs and symptoms of TB) [3,6]. Here, CD4 is linked to tuberculosis.