JAMA · 2005 · 433 citations · 21 references
Public HealthImmunologyInfectious DiseasesClinical ImmunologyEarly DetectionImmunizationLatent Tuberculosis InfectionMycobacterial DiagnosticsTuberculosis DiagnosisTuberculosis Diagnostic TestingTuberculosis PreventionTuberculosis VaccinationInterferon Gamma ProductionInterferon Gamma ResponseInterferon-gamma Release Assay ScreeningLatent Tuberculosis Infection ScreeningLatent Tuberculosis ScreeningMycobacterium Tuberculosis InfectionTuberculosis DiagnosticsTuberculosis Screening
Latent tuberculosis infection is difficult to diagnose, especially in BCG‑vaccinated populations where the tuberculin skin test has limited specificity. This study aimed to compare the performance of a whole‑blood interferon‑γ assay using ESAT‑6 and CFP‑10 antigens with the tuberculin skin test for diagnosing latent TB infection across different exposure risk groups. In a prospective cohort of 273 BCG‑vaccinated Korean adults, participants were stratified into four risk groups and tested sequentially with a 2‑TU PPD RT23 skin test and the whole‑blood IFN‑γ assay. The IFN‑γ assay showed markedly higher positive rates in higher‑risk groups, a stronger association with exposure (odds ratio 5.31 vs 1.52 for TST), and only modest agreement with the TST (kappa = 0.16), indicating it is a superior indicator of latent TB infection in this setting.
A recently developed whole-blood interferon gamma (IFN-gamma) assay based on stimulation with the Mycobacterium tuberculosis-specific antigens early secreted antigenic target 6 and culture filtrate protein 10 shows promise for the diagnosis of latent tuberculosis (TB) infection.To compare the tuberculin skin test (TST) and the whole-blood IFN-gamma assay in the diagnosis of latent TB infection according to the intensity of exposure.A prospective comparison between the whole-blood IFN-gamma assay and the TST using a 2-TU dose of purified protein derivative RT23 in a population with intermediate TB burden was conducted sequentially between February 1, 2004, and February 28, 2005, in a Korean tertiary referral hospital.Of 273 participants, 220 (95.7%) had received BCG vaccine. Participants were grouped according to their risk of infection: group 1, no identifiable risk of M tuberculosis infection (n = 99); group 2, recent casual contacts (n = 72); group 3, recent close contacts (n = 48); group 4, bacteriologically or pathologically confirmed TB patients (n = 54).Levels of agreement between the TST and the IFN-gamma assay and the likelihood of infection in the various groups.For the TST with a 10-mm induration cutoff, the positive response rate in group 1 was 51%; group 2, 60%; group 3, 71%, and group 4, 78%. For the IFN-gamma assay, the positive response rate in group 1 was 4%; group 2, 10%; group 3, 44%; and group 4, 81%. The overall agreement between the TST and the IFN-gamma assay in healthy volunteers was kappa = 0.16. The odds of a positive test result per unit increase in exposure across the 4 groups increased by a factor of 5.31 (95% confidence interval [CI], 3.62-7.79) for the IFN-gamma assay and by a factor of 1.52 (95% CI, 1.20-1.91) for the TST (P<.001). Using a 15-mm induration cutoff for the TST did not make a substantial difference to the test results.The IFN-gamma assay is a better indicator of the risk of M tuberculosis infection than TST in a BCG-vaccinated population.
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Christopher Dye, S Scheele, Vikram Pathania et al. · JAMA · 1999 · 3K citations
Public Health, Infectious Disease Control, Infectious Diseases +17
Comparative Genomics of BCG Vaccines by Whole-Genome DNA Microarray
Marcel A. Behr, Michael A. Wilson, Wendy Gill et al. · Science · 1999 · 1.5K citations
Measurement of Delayed Skin-Test Responses
Joseph E. Sokal · New England Journal of Medicine · 1975 · 506 citations
Life Sciences, Immunology, Oncology +10