Rational use of immunodiagnostic tools for tuberculosis infection: guidelines and cost effectiveness studies.
Tuberculosis (TB) remains a public health challenge and its control requires the use efficient diagnostic tools. Mycobacterium tuberculosis (MTB) elicits a strong immune response upon infection, a phenomenon measured by the old tuberculin skin test (TST). However, this test has many limitations and a high rate of positivity in BCG-vaccinated subjects. Recent studies have identified several MTB-antigens for diagnostic use, including the ESAT-6 and CFP-10 proteins. Based on these antigens, one of the most significant developments in the diagnostic armamentarium for TB has been the assays based on IFN- determination (IGRAs). The assays stem from the principle that T-cells of infected individuals produce IFN-gamma when they re-encounter the MTB antigens in vitro and this can be measured by a conventional ELISA test. The evaluation of IGRAs in different clinical settings showed many advantages over TST. The worldwide diffusion of IGRAs has increased the knowledge on their clinical use and a number of guidelines have been devised for their application. The two-step approach (first using TST followed by IGRA for confirmation) is the most favored strategy for IGRA-use in the general population, while the use of IGRAs alone is suggested in particular clinical settings and/or patient groups. Even if these tests are still costly there are a number of cost effective advantages in the "targeted" use of IGRAs over the TST. The work we present summarises all these aspects.
Amicosante
Massimo
M
Department of Internal Medicine, University of Rome "Tor Vergata", Rome, Italy. Massimo.amicosante@uniroma2.it
Ciccozzi
Massimo
M
Markova
Roumiana
R
D000942:Antigens, Bacterial / Q000276:immunology; D003362:Cost-Benefit Analysis; D017408:Guidelines as Topic; D006801:Humans; D007159:Immunologic Tests / Q000191:economics* / Q000379:methods / Q000592:standards*; D007371:Interferon-gamma; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D014376:Tuberculosis / Q000175:diagnosis* / Q000276:immunology; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis / Q000276:immunology
D000942:Antigens, Bacterial; C072681:Mycobacterium tuberculosis antigens; D007371:Interferon-gamma