Diagnostic Study: Enhanced prediction of TB progression with IGRAs compared to tuberculin skin test
27 Apr, 2024 | 18:53h | UTCStudy Design and Population:
This prospective diagnostic study analyzed the predictive accuracy of tuberculosis (TB) tests among 22,020 high-risk participants across 10 US sites from 2012 to 2020. Participants included individuals with close contacts to infectious TB cases, those born in or travelers to high-incidence countries, individuals living with HIV, or belonging to locally prevalent high-risk groups. Testing included two interferon-γ release assays (IGRAs), QuantiFERON-TB Gold In-Tube (QFT-GIT) and SPOT.TB (TSPOT), alongside the traditional tuberculin skin test (TST).
Main Findings:
The study found that both IGRAs, TSPOT and QFT-GIT, showed significantly superior positive predictive value (PPV) for predicting TB disease progression compared to the TST, with PPV ratios of 1.65 (95% CI, 1.35-2.02) and 1.47 (95% CI, 1.22-1.77) respectively. Additionally, when considering a positive TST result, further positive results from either IGRA significantly increased the PPV, emphasizing the enhanced predictive capability of IGRAs over TST alone.
Implications for Practice:
The superior predictive performance of Interferon-γ Release Assays (IGRAs) suggests they should be considered in clinical settings for high-risk populations, if available and feasible, to better identify individuals at increased risk of progressing to active tuberculosis (TB). This enhanced detection capability could guide more targeted preventive treatments, ultimately supporting global efforts toward TB elimination. Clinicians should assess the accessibility and cost-effectiveness of IGRAs to refine decision-making processes in TB prevention strategies, ensuring that the benefits of these advanced diagnostics are balanced against their costs.
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