QIAreach® QuantiFERON-TB diagnostic performance to detect tuberculosis infection among people living with HIV in Brazil: A prospective study

BACKGROUND: Identifying individuals with tuberculosis infection (TBI) at increased risk of progressing to active TB remains challenging. The World Health Organization recommends both the tuberculin skin test (TST) and the interferon-gamma release assay (IGRA), including QuantiFERON-TB Gold Plus (QFT®-Plus), for the detection of TBI. QIAreach®, a novel IGRA assay designed for resource-limited settings, has shown strong concordance with QFT®-Plus. However, data on immunosuppressed individuals are limited. To address this gap, we assessed the diagnostic performance of QIAreach® compared with QFT®-Plus in a high TB/HIV-burden setting. METHODS: We prospectively evaluated QIAreach® at an HIV reference center in Manaus, Brazil. Blood samples from PLHIV aged ≥ 18 years with CD4 cell counts ≥ 350 cells/mm³ or with unavailable CD4 results at enrollment were tested using both assays per manufacturer instructions. Diagnostic performance (sensitivity, specificity, and predictive values) was assessed using QFT®-Plus as the reference standard. Cohen's kappa coefficient determined test agreement. RESULTS: Among 266 participants (median age 37 years; 70% men; median CD4 537 cells/mm³), QIAreach® sensitivity, specificity, and negative predictive value (95% CI) were 0.97 (0.90-1.00), 0.73 (0.66-0.78), and 0.99 (0.96-0.99), respectively. Concordance (Cohen's kappa) was 0.36. CONCLUSION: QIAreach® demonstrated high sensitivity and negative predictive value (NPV) in PLHIV. However, its increased false-positive rate affected specificity. Given its high NPV, further studies are needed to determine its role as a point-of-care triage test for TBI.