TB QuantiFERON®-TB Gold (IGRA TB Test)

Why test for TB QuantiFERON®-TB Gold (IGRA TB Test)

TB QuantiFERON®-TB Gold is used to screen for tuberculosis infection that is active or latent. Doctor advices for this test if a person is exposed to a person with TB or if a person has clinica conditions or risk factors that can cause acitve TB infection.

The IGRA test measures the release of a substance called gamma interferon by white blood cells in a sample of blood when the cells are exposed to specific TB antigens. The IGRA test is not performed by all laboratories. The test requires viable white blood cells, so the IGRA blood sample must be received and tested by a laboratory within a designated window of time.

Recommendations from the Centers for Disease Control and Prevention (CDC), the Infectious Diseases Society, of America (IDSA), and the American Thoracic Society (ATS) list a preference for an IGRA test when:

• Someone is unlikely to return to have their TST evaluated
• The person is 5 years or older
• Is likely to be infected with latent TB
• Has a low to intermediate risk of progressing to active tuberculosis
• A test for latent tuberculosis infection (LTBI) is warranted
• And/or if the person being tested has received the BCG (Bacille Calmette-Guérin) vaccine that might interfere with the interpretation of a TST. BCG is not used as a vaccine in the United States, but it is often routinely administered in countries with a higher incidence of TB and it is used in the U.S. as a treatment for some cancers.