IFN-γ release assay versus tuberculin skin test for monitoring TB infection in healthcare workers.

Healthcare workers (HCW) are a risk group for TB. Even in countries with low TB incidence, the risk of TB in HCW is elevated for a wide range of tasks in healthcare, and the prevention of nosocomial infection of HCW remains as a challenge. IFN-γ release assays (IGRA) facilitate the screening of HCW for latent TB infection. In comparison with the tuberculin skin test, the IGRA reduces the number of x-rays and the amount of chemoprevention needed. However, a borderline zone should be introduced for the interpretation of IGRA results in the serial testing of HCW. More data on disease progression depending on conversion and reversion in IGRA is needed and a better test, which is able to distinguish recent from remote latent TB infection, would be desirable in the future.