The use of Interferon-γ release assays for Tuberculosis Screening in International TravelersArchived
IGRAs are increasingly being considered for the diagnosis of LTBI, as a replacement to the TST, including travel medicine. As with the TST, many uncertainties remain with regard to the efficacy of the IGRAs. It is therefore essential to secure an accurate understanding of these assays‘ known efficacy, so that they be optimally used and only in context with proven effect.
Apers L, Yansouni C, Soentjens P, Vekemans M, Bottieau E. Current Infectious Diseases Report Feb 2011
Description
This review of published literature presents the characteristics of interferon-gamma release assays (IGRAs) for the diagnosis of latent tuberculosis infection (LTBI) in a travel clinic setting. It presents the most recent reviews and meta-analyses on accuracy of the IGRAs and compares it to that of the tuberculin skin test (TST), also taking into the consideration different population groups to consider when testing for LTBI. The data presented shows that the two commercially available IGRAs (QFT-GIT and T-Spot.TB) in general have a similar sensitivity and superior specificity as compared to TST. However, authors state that the replacement of TST for IGRAs is often not recommended by experts due to the many uncertainties that remain in interpreting IGRA test results, and that experts rather recommend the IGRAs be used in combination with the TST; a reflection of the lack of a gold standard for diagnosing LTBI. The uncertainties with regard to the IGRAs efficacy and role in diagnosing LTBI is further reflected in current policies and guidelines for TB testing in the USA, UK, Canada and the Netherlands, as presented in the current paper. Authors conclude that for travel clinic practices, the choice of TST, IGRA or combination of TST and IGRA for diagnosing LTBI should reflect current policy guidelines, logistical and financial implications. Furthermore, authors highlight the importance that each patient’s place of origin, medical history and history of travel be considered when interpreting test results for LTBI.
Public Health significance
IGRAs are increasingly being considered for the diagnosis of LTBI, as a replacement to the TST, including travel medicine. As with the TST, many uncertainties remain with regard to the efficacy of the IGRAs. It is therefore essential to secure an accurate understanding of these assays‘ known efficacy, so that they be optimally used and only in context with proven effect.
ECDC has recently launched a guidance document on the “Use of IGRAs in support of diagnosing tuberculosis”
Link to the article: "The Use of Interferon-γ Release Assays for Tuberculosis Screening in International Travelers"
