Diagnostic accuracy of interferon-gamma release assays for diagnosis of smear-negative pulmonary tuberculosis: a systematic review and meta-analysis.

Introduction: The diagnosis of smear-negative pulmonary tuberculosis (SNPTB) is challenging. Interferon gamma-release assays (IGRAs) may be helpful in early diagnosis among these patients resulting in prompt treatment and favorable outcomes.
Methods: We performed a comprehensive search from each databases' inception to April 5, 2021. The studies that provided sufficient data regarding the sensitivity and specificity of IGRAs included QuantiFERON-TB Gold In-Tube (QFT-GIT), T-SPOT.TB, or QuantiFERON-TB Gold Plus for diagnosis of SNPTB were included.
Results: Of 1,312 studies screened, 16 studies were included; 11 QFT-GIT, 2 T-SPOT.TB, and 3 QFT-GIT and T-SPOT.TB. For diagnosis of SNPTB, QFT-GIT had sensitivity of 0.77 (95% CI 0.71-0.82), specificity of 0.70 (95% CI 0.58-0.80), diagnostic odds ratio (DOR) of 8.03 (95% CI 4.51-14.31), positive likelihood ratio (LR) of 2.61 (95% CI 1.80-3.80), negative LR of 0.33 (95% CI 0.25-0.42), and area under receiver operating characteristic (AUROC) of 0.81 (95% CI 0.77-0.84). T-SPOT.TB had sensitivity of 0.74 (95% CI 0.71-0.78), specificity of 0.71 (95% CI 0.49-0.86), DOR of 6.96 (95% CI 2.31-20.98), positive LR of 2.53 (95% CI 1.26-5.07), negative LR of 0.36 (95% CI 0.24-0.55), and AUROC of 0.77 (95% CI 0.73-0.80). The specificity seemed lower in the subgroup analyses of studies from high tuberculosis burden counties compared to the studies from low tuberculosis burden.
Conclusion: IGRAs do have insufficient diagnostic performance for SNPTB. However, the tests are still helpful to exclude tuberculosis among patients with low pre-test probability. Registry: PROSPERO: CRD42021274653.
(© 2022. The Author(s).)