SAM is associated with depressed delayed-type hypersensitivity responses, which would be expected to reduce the sensitivity of tests that rely on demonstrating cellular memory immune responses.57,58 IGRA tests are performed by measuring interferon-gamma (IFNγ) release by immune cells either i) without stimulation, ii) with a non-specific immune stimulant, and iii) with TB-derived proteins. This evidence concerns the gene IFNG and tuberculosis.