Prospective Comparison of QFT-GIT and T-SPOT.TB Assays for Diagnosis of Active Tuberculosis

Abstract

T-SPOT.TB and QuantiFERON-TB Gold In-Tube (QFT-GIT) tests, as two commercial blood assays for diagnosing active tuberculosis (ATB), are not yet fully validated. Especially, there are no reports on comparing the efficacy between the two tests in the same population in China. A multicenter, prospective comparison study was undertaken at four hospitals specializing in pulmonary diseases. A total of 746 suspected pulmonary TB were enrolled and categorized, including 185 confirmed TB, 298 probable TB and 263 non-TB. Of 32 patients with indeterminate test results (ITRs), age and underlying disease were associated with the rate of ITRs. Furthermore, the rate of ITRs determined by T-SPOT.TB was lower than QFT-GIT (0.4% vs. 4.3%, P < 0.01). When excluding ITRs, the sensitivities of T-SPOT.TB and QFT-GIT were 85.2% and 84.8%, and specificities of 63.4% and 60.5%, respectively in the diagnosis of ATB. The two assays have an overall agreement of 92.3%, but exhibited a poor linear correlation (r2 = 0.086) between the levels of interferon-γ release detected by the different assays. Although having some heterogeneity in detecting interferon-γ release, both the QFT-GIT and T-SPOT.TB demonstrated high concordance in diagnosing ATB. However, neither of them showed suitability in the definitive diagnosis of the disease.

Pulmonary sarcoidosis as a cause of intermittent fever of unknown origin in a hemodialysis patient with renal cell carcinoma: A case report and literature review

“…Particularly, extrapulmonary tuberculosis is more frequent in hemodialysis patients than in healthy people . The TSPOT‐TB test is useful for diagnosing active tuberculosis . In addition, CRP level is usually increased in pulmonary and extrapulmonary tuberculosis .…”

“…12 The TSPOT-TB test is useful for diagnosing active tuberculosis. 13 In addition, CRP level is usually increased in pulmonary and extrapulmonary tuberculosis. 14 Therefore, we also considered tuberculosis less likely.…”

Use of T Cell Mediated Immune Functional Assays for Adjustment of Immunosuppressive or Anti-infective Agents in Solid Organ Transplant Recipients: A Systematic Review

“…This decreases the risk of false-positive results in individuals who have received the BCG vaccine or who are infected with other strains of mycobacteria. IGRAs, however, have a high number of indeterminate results and poor reproducibility mainly in immunocompromised patients (23)(24)(25)(26). In comparison with QuantiFERON R -TB Gold, the T-SPOT R .TB assay is more laborious, takes more time, and needs specific laboratory equipment for purification of PBMCs (27,28).…”

Testing for Mycobacterium tuberculosis infection using the QuantiFERON-TB GOLD assay in patients with comorbid conditions in a tertiary care endemic setting

“…Interferon gamma release assays (IGRAs) such as, QuantiFERON TB Gold in tube assay (QFT-GIT) measure specific T cell-based responses to MTB-specific antigens including Early secretory antigen target (ESAT)-6, Culture filtrate protein (CFP)-10 and TB 7.7 [6]. T SPOT-TB is an IGRA which requires purified mononuclear cells to quantify IFNgamma (IFN-γ) responses [7]. QFT-GIT uses whole blood and is more convenient to use but may be affected by the number of mononuclear cells present in the test sample [7].…”

“…T SPOT-TB is an IGRA which requires purified mononuclear cells to quantify IFNgamma (IFN-γ) responses [7]. QFT-GIT uses whole blood and is more convenient to use but may be affected by the number of mononuclear cells present in the test sample [7]. QFT-GIT is more specific than TST for identification of LTBI, is unaffected by BCG vaccination [8] and can be useful as a confirmatory test to rule out false positives results [9].…”