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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
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BMC Infectious Diseases

ISSN: 1471-2334

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