The Mantoux tuberculin skin test is often used to screen people at high risk for TB. Those who have been previously immunized may have a false-positive test result. The test may be falsely negative in those with sarcoidosis, Hodgkin's lymphoma, malnutrition, and most notably, active tuberculosis. Interferon gamma release assays (<answer>IGRAs</answer>), on a blood sample, are recommended in those who are positive to the Mantoux test. These are not affected by immunization or most environmental mycobacteria, so they generate fewer false-positive results. However, they are affected by M. szulgai, M. marinum, and M. kansasii. <answer>IGRAs</answer> may increase sensitivity when used in addition to the skin test, but may be less sensitive than the skin test when used alone.
Which test has fewer false positives: IGRAs or the Mantoux skin test?
IGRAs