IFN-γ Release Assays to Detect Latent TB

Among individuals exposed to active TB, skin-test reactions ≥15 mm were associated only with age; blood-test results were associated with degree of exposure.

In countries with low TB incidence, tracing and treating persons with latent TB infection are the cornerstone of control. Because the tuberculin skin test (TST) has low specificity among individuals who have received bacille Calmette-Guérin (BCG) vaccine or have been exposed to environmental mycobacteria, a more accurate test is needed to detect latent infection and target treatment. Interferon-γ (IFN-γ) release assays (IGRAs) — whole-blood tests that measure the amount of IFN-γ released after in vitro incubation with TB antigens — appear to be very specific.

In a study involving 785 BCG-unvaccinated adults who were exposed to TB in a Netherlands supermarket, researchers compared the results of the TST with those of two IGRAs: the QuantiFERO…

Reviewing Author

Neil M. Ampel, MD

IFN-γ Release Assays to Detect Latent TB

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Reviewing Author