title: Diagnosis of tuberculosis infection using interferon-γ-based assays.
abstract: Interferon-γ-based assays, collectively known as IFN-γ release assays (IGRAs), have emerged as a reliable alternative to the old tuberculin skin test (TST) for the immunodiagnosis of tuberculosis (TB) infection. The 2 commercially available tests, the enzyme-linked immunosorbent assay (ELISA), QuantiFERON-TB Gold Intube (QFT-IT), and the enzyme-linked immunospot assay (ELISPOT), T-SPOT.TB, are more accurate than TST for the diagnosis of TB, since they are highly specific and correlate better with the existence of risk factors for the infection. According to the available data, T-SPOT.TB obtains a higher number of positive results than QFT-IT, while its specificity seems to be lower. Although the sensitivity of the IFN-γ -based assays may be impaired to some extent by cellular immunosuppression and extreme ages of life, they perform better than TST in these situations. Data from longitudinal studies suggest that IFN-γ-based tests are better predictors of subsequent development of active TB than TST; however this prognostic value has not been consistently demonstrated. This review focuses on the clinical use of the IFN-γ -based tests in different risk TB groups, and notes the main limitations and areas for future development.
authors.affiliation: Servicio de Enfermedades Infecciosas, Hospital Universitario de Bellvitge, IDIBELL, Departamento de Ciencias Clínicas, Universidad de Barcelona, Red Española de Investigación en Patología Infecciosa, Instituto de Salud Carlos III, Barcelona, Spain. msantin@bellvitgehospital.cat
authors.forename: Miguel
authors.initials: M
authors.lastname: Santín Cerezales
authors.forename: José
authors.initials: J
authors.lastname: Domínguez Benítez
mesh_terms: D000368:Aged; D015415:Biomarkers; D001826:Body Fluids / Q000737:chemistry; D015897:Comorbidity; D016358:Contact Tracing; D004797:Enzyme-Linked Immunosorbent Assay; D058501:Enzyme-Linked Immunospot Assay; D005544:Forecasting; D006801:Humans; D016867:Immunocompromised Host; D007371:Interferon-gamma / Q000032:analysis* / Q000097:blood; D055985:Latent Tuberculosis / Q000175:diagnosis / Q000453:epidemiology; D009784:Occupational Diseases / Q000175:diagnosis; D011237:Predictive Value of Tests; D011379:Prognosis; D012306:Risk; D012680:Sensitivity and Specificity; D014374:Tuberculin Test; D014376:Tuberculosis / Q000175:diagnosis* / Q000453:epidemiology; D014390:Tuberculosis, Meningeal / Q000175:diagnosis; D035862:Vulnerable Populations
chemical_list: D015415:Biomarkers; D007371:Interferon-gamma