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Table 3 Accuracy of CXR and CXR plus GeneXpert in smear-negative TB diagnosis among TB-treatment naïve participants

From: Chest X-ray interpretation does not complement Xpert MTB/RIF in diagnosis of smear-negative pulmonary tuberculosis among TB-HIV co-infected adults in a resource-limited setting

Accuracy index

CXR Interpretation

CXR plus Xpert MTB/RIF test

Sensitivity (95% CI)

67.6% (55.7–78)

86.5% (76.5–93.3)

Specificity (95% CI)

59.6% (52.8–66)

57.3% (50.6–63.9)

PPV (95% CI)

35.5% (27.6–44)

40% (32.3–48)

NPV (95% CI)

84.8% (78.2–90)

92.8% (87.2–96.5)

Likelihood ratio (+)

1.67 (1.34–2.09)

2.03 (1.7–2.42)

Likelihood ratio (−)

0.545 (0.385–0.77)

0.236 (0.131–0.424)

AUC (ROC area)

0.636 (0.573–0.698)

0.719 (0.668–0.77)

  1. CI Confidence Intervals; CXR Chest X-ray; PPV Positive predictive value; NPV Negative predictive value; (+),Positive; (−), Negative; ROC Receiver Operating Characteristic curve
  2. Table 3 shows accuracy of CXR interpretation and when CXR is combined with Xpert MTB/RIF for the diagnosis of smear-negative TB among TB treatment naive HIV-positive patients using Mycobacterial cultures as reference standard.
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BMC Infectious Diseases

ISSN: 1471-2334

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