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.