Clinical utility of interferon gamma assay in the diagnosis of tuberculosis.

Newly developed assays that measure the production of cellular interferon gamma are useful diagnostic tools for the diagnosis of tuberculosis and may potentially replace or complement the tuberculin skin test in some circumstances. Importantly, interferon gamma release assays are more specific than tuberculin skin tests. Unfortunately the tests do not differentiate between active or latent infection. In addition, immunocompromised patients are more likely to have indeterminate results. The current interferon gamma release assays test approved in the United States is costly and requires drawing blood and processing within 12 hours of collection. This study discusses the potential benefits and drawbacks in patients, including those who are immunocompromised.