Skip to main content

Table 2 Diagnostic accuracy of the IFN-γ/TNF-α FluoroSpot assay for differentiating ATB from LTBI (Stimulated by ESAT-6 peptide)

From: Utility of interferon gamma/tumor necrosis factor alpha FluoroSpot assay in differentiation between active tuberculosis and latent tuberculosis infection: a pilot study

  Sensitivity
(%, 95CI)
Specificity
(%, 95CI)
PLR
(95%CI)
NLR
(95%CI)
PPV
(%, 95CI)
NPV
(%, 95CI)
Frequencies of total TNF-α-secreting T cells 96.7 (82.8–99.9) 94.3 (80.8–99.3) 16.92 (4.40–65.08) 0.04 (0.01–0.24) 93.6 (78.6–99.2) 97.1 (84.7–99.9)
Frequencies of total IFN-γ-secreting T cells 90.0 (73.5–97.9) 77.1 (59.9–89.6) 3.94 (2.12–7.32) 0.13 (0.04–0.39) 77.1 (59.9–89.6) 90.0 (73.5–97.9)
Parallel test
 With the OR rule* 96.7 (82.8–99.9) 74.3 (56.7–87.5) 3.76 (2.13–6.63) 0.04 (0.01–0.31) 76.3 (59.8–88.6) 96.3 (81.0–99.9)
 With the AND rule# 90.0 (73.5–97.9) 97.1 (85.1–99.9) 31.50 (4.55–218.21) 0.10 (0.04–0.30) 96.4 (81.7–99.9) 91.9 (78.1–98.3)
  1. If the frequencies of total TNF-α-secreting T cells were greater than 21 iSFCs/2.5 × 105 PBMC, AND more than twice as large as that of the nil control, the result of TNF-α FluoroSpot assay was considered positive. If the frequencies of total IFN-γ-secreting T cells were greater than 23 iSFCs/2.5 × 105 PBMC, AND more than twice as large as that of the nil control, the result of IFN-γ FluoroSpot assay was considered positive.
  2. *The OR rule, in which the diagnosis is positive if either test is positive
  3. #The AND rule, in which the diagnosis is positive only if both tests are positive
  4. Abbreviations: ATB, active tuberculosis; LTBI, latent tuberculosis infection; ESAT-6, 6-kDa early-secreted antigenic target; PLR, positive likelihood ratio; NLR, negative likelihood ratio; PPV, positive predictive value; NPV, negative predictive value; iSFCs, immunofluorescence spot forming cells; PBMC, peripheral blood mononuclear cells