Objective: To evaluate the sensitivity of an interferon-gamma release assay T-SPOT. TB in the diagnosis of bacteriologically or histologically confirmed extrapulmonary tuberculosis.
Method: Totally 31 patients with bacteriologically or histologically confirmed extrapulmonary tuberculosis in Peking Union Medical College Hospital received T-SPOT. TB assay to detect early secreting antigen target 6 or culture filtrate protein 10 peptides-specific T cells in the peripheral blood mononuclear cells (PBMCs).
Results: T-SPOT. TB assay showed positive results in 29 patients with extrapulmonary tuberculosis and the sensitivity was 93.5% (95% CI 84.8% - 100%). The median of spot forming cells (SFCs) in response to early secreting antigen target 6 peptides was 196/10(6) PBMCs (interquartile range, 72-532/10(6) PBMCs), the median of SFCs in response to culture filtrate protein 10 peptides was 276 SFCs/10(6) PBMCs (interquartile range, 72-568/10(6) PBMCs), and the median of the incorporate SFCs was 612/10(6) PBMCs (interquartile range, 192-1 152/10(6) PBMCs).
Conclusion: T-SPOT. TB is highly sensitive in diagnosing extrapulmonary tuberculosis.