OBJECTIVES: To present an updated review concerning new assays for diagnosing tuberculosis based on in vitro interferon-gamma production by host T cells, and compare them with tuberculin skin test. SOURCES: A literature review was carried out based on Medline and LILACS databases (2000-2008) searching for the following keywords: tuberculosis, interferon-gamma, quantiFERON, ELISPOT and T-SPOT.TB. SUMMARY OF THE FINDINGS: These new assays proved to have, in general, equal or superior sensitivity and specificity than the tuberculin skin test not only in adults but also in children and immunosuppressed patients for the diagnosis of both latent tuberculosis infection or active disease, with some advantages such as less cross-reactivity as a result of previous BCG vaccination, less influence of anergy and better accuracy in small children. In the United States, these assays have been used instead of the tuberculin skin test and, although still very expensive, the World Health Organization will be making its economic viability a priority. CONCLUSIONS: Always having in mind the importance of clinical and epidemiological histories, these new assays based on interferon-gamma release present promising results and should be considered in tuberculosis investigation procedures for all patients, however with a special concern in the risk groups (i.e., children and immunosuppressed patients).
Tuberculosis; interferon-gamma; quantiFERON; ELISPOT; children; immunosuppression
