An experimental diagnostic test to determine whether a person has an active or latent tuberculosis (TB) infection shows promise, according to preliminary findings by investigators from the Catholic University of Rome and other centers there (Delogu G et al. PLoS One. 2011;6:e18315).
This new test builds on a recently developed blood test for TB called interferon γ release assay (IGRA) that detects the release of IFN-γ in response to Mycobacterium tuberculosis– specific antigens. Because IGRA is unable to distinguish between latent and active TB infection, researchers added a blood test that detects a protein from the bacillus, heparin-binding hemagglutinin (HBHA). The response to HBHA is lower in active TB than in latent TB.
Friedrich MJ. Active vs Latent TB. JAMA. 2011;305(19):1953. doi:10.1001/jama.2011.635