IGRA can be used in any evaluation for tuberculosis infection (active or latent). |
IGRA are more specific than TSTs, which may be positive because of previous BCG vaccination or exposure to non-tuberculosis Mycobacterium. |
A positive IGRA indicates tuberculosis infection but does not differentiate between active or latent infection. |
A negative IGRA excludes tuberculosis in immunocompetent patients. |
Immunosuppressed patients are more likely to have indeterminate results. |
IGRA does not require a second visit to read the results. |
IGRA is more costly and requires processing within 12 hours of collection. |
IGRA, interferon gamma release assays; TST, tuberculin skin test; BCG, Bacillus Calmette-Guérin.