Table 2 Accuracy of CXR interpretation and when combined with Xpert MTB/RIF in HIV-related smear-negative TB diagnosis

Overall

Sensitivity (95% CI)

67.9% (56.6–77.8)

65.4% (54.0–75.7)

87.7% (78.5–93.9)

Specificity (95%CI)

53.7% (47.7–59.6)

95.8% (92.8–97.8)

51.6% (45.6–57.5)

PPV (95% CI)

29.4% (23.0–36.5)

81.5% (70.0–90.1)

34.0% (27.6–40.8)

NPV (95% CI)

85.5% (79.4–90.3)

90.7% (86.8–93.7)

93.6% (88.6–96.9)

Likelihood ratio (+)

1.47 (1.21–1.78)

15.54 (8.74–27.64)

1.81 (1.57–2.09)

Likelihood ratio (−)

0.60 (0.43–0.84)

0.36 (0.27–0.49)

0.24 (0.13–0.43)

Area under ROC curve

0.61 (0.55–0.67)

0.81 (0.75–0.86)

0.70 (0.65–0.74)

Inpatients

Sensitivity

66.2% (53.4–77.4)

64.6% (51.8–76.1)

86.2% (75.3–93.5)

Specificity

50.3% (42.8–57.7)

95.7% (91.7–98.1)

48.1% (40.7–55.6)

PPV (95% CI)

31.9% (24.1–40.4)

84.0% (70.9–92.8)

36.8% (29.2–45.0)

NPV (95% CI)

80.9% (72.5–87.6)

88.5% (83.2–92.6)

90.8% (83.3–95.7)

Likelihood ratio (+)

1.33 (1.06–1.67)

14.94 (7.41–30.13)

1.66 (1.40–1.97)

Likelihood ratio (−)

0.67 (0.47–0.97)

0.37 (0.27–0.51)

0.29 (0.15–0.54)

Area under ROC curve

0.58 (0.51–0.65)

0.80 (0.74–0.86)

0.67 (0.62–0.73)

Outpatient

Sensitivity

75.0% (47.6–92.7)

68.8% (41.3–89.0)

93.8% (69.8–99.8)

Specificity

60.0% (49.7–69.7)

96.0% (90.1–98.9)

58.0% (47.7–67.8)

PPV (95% CI)

23.1% (12.5–36.8)

73.3% (44.9–92.2)

26.3% (15.5–39.7)

NPV (95% CI)

93.8% (84.8–98.3)

95.0%(88.8–98.4)

98.3% (90.9–100)

Likelihood ratio (+)

1.88 (1.29–2.72

17.19 (6.23–47.45)

2.23 (1.72–2.90)

Likelihood ratio (−)

0.42 (0.18–0.99)

0.33 (0.16–0.67)

0.11 (0.02–0.72)

Area under ROC curve

0.67 (0.56–0.79)

0.82 (0.70–0.94)

0.76 (0.68–0.84)