Potential use of in vitro tests in the diagnosis of tuberculosis (literature review)

SummaryThe search for methods to improve early diagnosis of tuberculosis has been particularly active in the last two decades. Diagnostics of latent tuberculosis infection will increase the efficacy of anti-tuberculosis measures. Tu-berculosis in HIV patients, which is increasingly common in the incident population, has specific clinical, immuno-logical, and pathomorphological characteristics posing challenges to diagnosis confirmation. HIV-infected indi-viduals have a 30-fold risk of tuberculosis compared with the general population. Diagnostic challenges are par-ticularly high at the stage of severe immunodeficiency. In the last two decades, IGRAs, which have a higher specifi-city versus tuberculin skin tests, have been increasingly used. We present a literature review of studies comparing the diagnostic efficacy of T-SPOT.TB and QuantiFERON-TB Gold in-Tube assays in patients with suspected active tuberculosis. According to literature data, QuantiFERON assay more frequently yields false negative results in HIV patients with markedly decreased CD4+ cell counts. T-SPOT.TB sensitivity is essentially independent of age, whereby the sensitivity of QuantiFERON-TB reduces after the age of 30 years. T-SPOT.TB assay was not found to be affected by drug therapy. Based on this literature review, we assume that the use of T-SPOT.TB assay is most ap-propriate in the following cases: in patients taking drugs that inhibit gamma interferon production (glucocorti-coids); in patients taking drugs that reduce leukocyte lev-els (NSAIDs: aspirin, paracetamol, Ketorol; also cytostatic agents etc.); in children under 5 years and in elderly sub-jects. T-SPOT.TB appears to be a promising test within the assessment of HIV-infected patients.