The evolution and role of interferon gamma release assays (IGRAs) in moderate and low income settings.

The interferon gamma release assays have been extensively evaluated in the diagnosis of latent tuberculosis infection as well as in diagnosis of active pulmonary and extra-pulmonary tuberculosis since their introduction just over a decade ago. The results and recommendations published are confusing to say the least. The performance of these tests vary according to the population they are used in, including age, BCG vaccination status and immune status, the commercial test used, the TB burden of the country/ region and other factors intrinsic to the tests themselves. This review attempts to summarize the evolution of the IGRAs, particularly in the context of moderate and low income settings where a large question about their use still remains. Much work needs to be done before definitive recommendations about their role in the diagnostic algorithms of low and middle income countries can be made, but problems associated with the tests including cost and interpretation issues may limit the amount of work that can be invested productively in this evaluation.

DOI: http://dx.doi.org/10.4038/sljid.v4i2.7153

Sri Lankan Journal of Infectious Diseases 2014; Vol.4(2):56-66