IFNG and malnutrition: Another study from South Africa suggested that while malnutrition adversely impacted the sensitivity of TST (from 63% to 44%), it did not affect IGRA sensitivity.62 This study used an ELISPOT-based assay that enumerates IFNγ-producing cells rather than IFNγ levels overall, and might hypothetically be more appropriate where moderate cellular anergy, or ‘unresponsiveness’ exists.