IFN-γ Release Assays vs. TST for Predicting Development of Active TB

Among individuals exposed to TB, 14.6% of those with a positive IFN-γ release assay developed active TB, compared with only 2.3% of those with a positive tuberculin skin test.

In areas with a low prevalence of TB, the cornerstone of control is to identify individuals with latent infection. Traditionally, the tuberculin skin test (TST) has been used for this purpose, but in vitro interferon (IFN)-γ release assays are also now available.

To compare these two testing approaches, researchers conducted a longitudinal cohort study in Hamburg, Germany, among 601 individuals with recent TB exposure. Each study participant was tested with both the TST and the QuantiFERON-TB Gold In-Tube (QFT) IFN-γ release assay at least 8 weeks after exposure. TSTs were scored as positive if indurations were >5 mm. Isoniazid chemopreventive therapy was offered only to individuals with positive QFT results.

During the 2-year study, active T…

Reviewing Author

Neil M. Ampel, MD

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Editorial BoardsUpToDate

Leadership Positions in Professional SocietiesCoccidioidomycosis Study Group (Past President, Secretary, Treasurer)

Neil M. Ampel, MD

Disclosures

Editorial BoardsUpToDate

Leadership Positions in Professional SocietiesCoccidioidomycosis Study Group (Past President, Secretary, Treasurer)

IFN-γ Release Assays vs. TST for Predicting Development of Active TB

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Reviewing Author