To the extent that the TB skin test is by default the standby test, the evidence is that IGRA outperforms the TST;
Newest commercial IGRAs are superior, in comparison to the TST, for detecting confirmed active TB disease, especially when performed in developed countries.Evidence based comparison of commercial interferon-gamma release assays for detecting active tuberculosis — a meta-analysis
R Diel1, R Loddenkemper2 and A Nienhaus3
+ Author Affiliations
1Department of Pulmonary Medicine, Medical School (MHH) Hannover, Germany
2German Central Committee against Tuberculosis, Lungenklinik Heckeshorn, HELIOS Klinikum Emil von Behring, Berlin, Germany
3Institution for Statutory Accident Insurance and Prevention in the Health and Welfare Services, Hamburg, Germany
Corresponding author: Roland Diel, MD, MPH, Assistant Professor, Department of Pulmonary Medicine, Medical School (MHH) Hannover, Carl-Neuberg-Straße 1, 30625 Hannover, Germany. Mail: Diel.Roland@mh-hannover.de, Phone: +49 (0) 1724578525, Fax : +49 (0) 511 532-3353
Abstract
Background: Test accuracy of interferon-gamma release assays (IGRAs) for diagnosing tuberculosis (TB) differs when utilizing older or pre-commercial tools and inconsistent diagnostic criteria. This meta-analysis critically appraises studies investigating sensitivity and specificity of the commercial T-Spot. TB and the in tube version of QuantiFERON-TB Gold (QFT-IT) among definitely confirmed TB cases.
Methods: We searched Medline, EMBASE and Cochrane bibliographies of relevant articles. Sensitivities, specificities and indeterminate rates were pooled using a fixed effect model. Sensitivity of the tuberculin skin test (TST) was evaluated in the context of IGRA studies. In addition, the rates of indeterminates of both IGRAs were assessed.
Results: The pooled sensitivity of TST was 70% [95% CI 0.67 to 0.72] compared with 81% [95% CI 0.78 to 0.83] for the QFT-IT and 88% [95% CI 0.86 to 0.90] for the T-SPOT.TB. Sensitivity increased to 84% [95%CI 0.81 to 0.87] and 90% [0.87 to 0.92] for the QFT-IT and T-Spot.TB, respectively, when restricted to performance in developed countries. In contrast, specificity of the QFT-IT was 99% [95% CI 0.98 to 1.00] versus 88% for the T-Spot. TB [0.84 to 0.91].
The pooled rate of indeterminate results was low, 2.1% [95% CI 0.02-0.023] for the QFT-IT and 3.8% [95% CI 0.035-0.042] for the T-Spot.TB, increasing to 4.4% [95% CI 0.039 to 0.05]) and 6.1% [95% CI 0.052 to 0.071], respectively, among immunosuppressed hosts.
Conclusions: Newest commercial IGRAs are superior, in comparison to the TST, for detecting confirmed active TB disease, especially when performed in developed countries.
Copyright © American College of Chest Physicians
