Evaluation of QIAreach QuantiFERON-TB for the diagnosis of Mycobacterium tuberculosis infection

Reducing the number of tuberculosis (TB) cases and deaths requires effective diagnosis and treatment of active TB as well as latent TB infection (LTBI) through TB preventive treatment (TPT). Interferon-gamma (IFN-γ) release assays (IGRAs) using blood samples offer advantages over tuberculin skin test (TST) for LTBI diagnosis, but current IGRAs are costly and require enzyme-linked immunosorbent assay (ELISA), making them more complicated and unsuitable for the district or provincial laboratories. QIAreach QuantiFERON-TB (QIAREACH-TB) is a novel IGRA that uses lateral flow immunoassay (LFA) and digital signal measurement to detect IFN-γ, providing a less resource-intensive alternative that eliminates the requirement for automated microplate washers and ELISA readers. We evaluated QIAREACH-TB for LTBI diagnosis using whole-blood samples from 154 healthcare workers (HCWs) and compared the results with QuantiFERON-TB Gold Plus (QFT-Plus). QFT-Plus detected M. tuberculosis infection in 26 (16.99%), while QIAREACH-TB detected infection in 30 (19.61%) samples. Our results demonstrated an overall percentage agreement (OPA) of 93.46% (95% confidence interval [95% CI]: 88.25-96.55%) between QIAREACH-TB and QFT-Plus. The positive percent agreement (PPA) was 88.46% (95% CI: 70.20-96.82%) while the negative percent agreement (NPA) was 94.49% (95% CI: 88.86-97.50%). The findings suggest that QIAREACH-TB is a practical alternative showing high concordance with QFT-Plus for detecting LTBI, requiring fewer laboratory resources and eliminating the need for ELISA equipment.