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An In Vitro Caseum Binding Assay that Predicts Drug Penetration in Tuberculosis Lesions
Published on: May 8, 2017
Two interferon gamma release assays for predicting active tuberculosis: the UK PREDICT TB prognostic test study.
Ibrahim Abubakar1, Ajit Lalvani2, Jo Southern3
1Institute for Global Health, University College London, London, UK.
A two-step approach combining the tuberculin skin test (TST) with an interferon gamma release assay (IGRA) is the most cost-effective strategy for identifying latent tuberculosis infection (LTBI) in high-risk individuals.
Area of Science:
- Public Health
- Infectious Disease Epidemiology
- Diagnostic Test Evaluation
Background:
- Tuberculosis (TB) incidence in the UK remains higher than in Western Europe.
- Latent TB infection (LTBI) detection and treatment are crucial for TB control.
- Evaluating diagnostic tests for LTBI is essential for at-risk populations.
Purpose of the Study:
- To compare the prognostic value of interferon gamma release assays (IGRAs) and the tuberculin skin test (TST) for predicting active TB.
- To assess the cost-effectiveness of different LTBI screening strategies.
- To evaluate tests for individuals at increased risk of TB, including contacts and migrants.
Main Methods:
- Prospective cohort study involving 10,045 participants at increased risk of TB.
- Comparison of TST, IGRA (T-SPOT.TB, QFT-GIT), and combined testing strategies.
- Economic analysis to determine the most cost-effective screening approach per QALY.
Main Results:
- A two-step TST combined with an IGRA was the most cost-effective LTBI testing strategy.
- TST alone was a poorer predictor of active TB progression compared to IGRAs and combinations.
- Dual-testing strategies demonstrated superior predictive value for progression to active TB.
Conclusions:
- While differences between tests were modest, a two-step TST/IGRA approach offers the best cost-effectiveness for LTBI screening.
- Current tests have limitations in predicting progression to active TB.
- Further investigation into the implications for national TB screening programs is warranted.
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