Table 7 Diagnostic performance of X-DOT-TB, QFT-Plus and TST assays.

From: Comparison of interferon gamma release assays and tuberculin skin test performance for diagnosing Mycobacterium tuberculosis infection in the Pakistani population

Diagnostic Parameters

Assays

X-DOT-TB (n = 325)

QFT-Plus (n = 126*)

TST (n = 322)

Sensitivity % (95% CI)

79.5 (77.4–81.5)

55.7 (52.9–58.5)

35.8 (34.4–37.1)

Overall Specificity % (95% CI)

85.1 (83.2–87.0)

78.1 (75.3–80.9)

82.2 (80.3–84.1)

PPV % (95% CI)

81.1 (79.0-83.2)

64.5 (61.4–67.5)

60.4 (58.5–62.2)

NPV % (95% CI)

79.6 (77.5–81.6)

70.3 (67.1–73.4)

60.2 (58.4–62.0)

LR+ (95% CI)

6.4 (5.8–6.9)

2.2 (1.7–2.6)

1.9 (1.6–2.2)

LR− (95% CI)

0.24 (-)

0.6 (0.5–0.7)

0.79 (0.63–0.95)

Accuracy % (95% CI)

79.1 (77.0-81.2)

56.6 (53.7–59.4)

36.6 (35.1–38.0)

Diagnostic Odd Ratio

26.6 (27.7–25.4)

3.6 (3.02–4.3)

2.4 (2.1–2.7)

  1. n: number; PPV: Positive predictive value; NPV: negative predictive value; LR+: Positive likelihood ratio; LR−: Negative likelihood ratio; CI: Confidence interval; TST: Tuberculin skin test.
  2. *Indeterminate QFT-Plus results (n = 2) were excluded from the analysis.
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