Interpretation

Positive: IFN-y response to Mycobacterium tuberculosis antigens, suggesting infection
with M. tuberculosis. For patients at low risk for infection, a second test or repeat test
should be considered. Prior infection with M. kansasii, M. szulgai and M. marinum may lead to false positive results

Negative: No IFN-y response to Mycobacterium tuberculosis antigens and infection with M. tuberculosis is unlikely. For patients at high risk for infection, a second test should be considered.

Indeterminate: Indeterminate results can result from either a poor response to positive control mitogen, which may be secondary to low lymphocyte count, decreased lymphocyte activity or immunosuppression, or from a high background (nil) response, which may be secondary to heterophile antibody effects or circulating IFN-y in the patient's blood.