A Test to Determine Risk for Developing Active Tuberculosis

A key strategy for preventing active tuberculosis (TB) entails treatment of patients with latent tuberculosis infection (LTBI). However, the risk for active TB is highest during the first 2 years after infection and declines after this period. Current tests, such as the QuantiFERON-TB Gold (QFT) assay (which measures release of interferon-γ [IFN-γ]), do not distinguish between latent and active disease and have poor predictive value for identifying those with LTBI most likely to develop active TB. Researchers hypothesized that persons recently infected or likely to progress to active infection would have a higher mycobacterial burden, which would be reflected in T-cell activation markers. Using data from South African observational TB studi…