WHAT IS RD1-INTERFERON TESTS FOR TUBERCULOSIS TEST (QUANTIFERON-TB GOLD (QFT-G), QUANTIFERON-TB GOLD IN-TUBE TEST (QFT-GIT), INTERFERON GAMMA RELEASE ASSAYS, IFN-GAMMA ASSAY, T-SPOT®.TB)?
These enzyme-linked immunoassays measure cell-mediated immune response by quantifying interferon (IFN)-gamma released by T cells in response to stimulation by Mycobacterium tuberculosis. The IFN-gamma is specific to M. tuberculosis and not to the BCG vaccine strain.
Thus, this test has particular value in detecting latent tuberculosis in clients who previously received BCG vaccination because it does not produce false-positive results as does tuberculin skin testing. Because it does not require two visits, as does the Mantoux skin test, the interferon tests are valuable for use in areas such as emerging countries where client follow-up is unreliable. In addition, because this test is an assay, it is not subject to reader error, as is the Mantoux test. The QuantiFERON-TB Gold (produced by Cellestis Ltd., Carnegie, Victoria, Australia) is included in the 2005 U.S. CDC guidelines for screening of health care workers.