Interferon-gamma release assay (IGRA)

Interferon-gamma release assay (IGRA) is a blood test used to detect if someone has been exposed to the bacteria that cause tuberculosis (TB). When tested, immune cells from the blood are exposed to TB proteins, and if the person has been infected before, these cells release a chemical called interferon-gamma. Measuring this chemical helps determine if the immune system has encountered TB bacteria. IGRA is more specific than traditional skin tests, requires only a blood sample, and is useful for diagnosing latent TB infection, guiding treatment decisions.