Interferon-gamma release assays (IGRAs)

Interferon-gamma release assays (IGRAs) are blood tests used to detect whether someone has been exposed to the bacteria that causes tuberculosis (TB). The test measures the immune response by checking if certain immune cells release a substance called interferon-gamma when exposed to TB-specific proteins. Unlike traditional skin tests, IGRAs do not require a second visit and are not affected by a person’s prior vaccination with the TB vaccine. They are especially useful for diagnosing TB in people who may not react to skin tests, such as those with weakened immune systems.