QuantiFERON TB Gold (QFT)

The QuantiFERON TB Gold (QFT) test is a modern blood test used to determine if a person has been infected with Mycobacterium tuberculosis, the bacterium that causes tuberculosis (TB). Unlike the traditional skin test, this is an Interferon-Gamma Release Assay (IGRA), making it highly specific and unaffected by prior BCG vaccinations.

The test measures your immune system response to TB-itemized proteins. When blood is mixed with these proteins, the T-cells of an infected person will release a cytokine called Interferon-gamma. The QuantiFERON-TB Gold test tells you if you have been infected, but it cannot distinguish between Latent TB and Active TB disease.