WHO operational handbook on tuberculosis: module 3: diagnosis: tests for TB infection. Web annex: use of alternative interferon-gamma release assays for the diagnosis of TB infection

This web annex to the WHO operational handbook on tuberculosis summarizes the evidence review and policy considerations regarding the use of alternative blood-based interferon-gamma release assays (IGRAs) for the diagnosis of tuberculosis (TB) infection. The document was developed to support WHO evaluation of new and updated IGRA technologies through the WHO Global TB Programme Pathway B assessment process. It presents the background to TB infection testing, describes the characteristics of currently available and emerging IGRAs, and outlines the methods and findings of a systematic review and meta-analysis comparing selected assays with WHO-recommended reference tests.

The publication reviews evidence on the diagnostic performance, agreement, reproducibility and implementation considerations of Beijing Wantai’s TB-IGRA, QuantiFERON-TB Gold Plus, QIAreach QuantiFERON-TB, Standard E TB-Feron ELISA and T-SPOT.TB 8 with T-Cell Select. Based on available evidence and deliberations of the WHO Technical Advisory Group on Tuberculosis Diagnostics and Laboratory Strengthening, the document concludes that Beijing Wantai’s TB-IGRA and QuantiFERON-TB Gold Plus show performance comparable to WHO-recommended IGRAs for detecting TB infection, while evidence for other evaluated assays remains insufficient for full comparison and recommendation.