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Table 5 Measures of diagnostic accuracy using culture as the reference standard

From: Evaluation of the performance of an in-house duplex PCR assay targeting the IS6110 and rpoB genes for tuberculosis diagnosis in Cameroon

 

Diagnostic method

Parameters

Direct microscopy

Concentrated microscopy

rpoB

IS6110

D-PCR

Number of samples negative

77

75

66

63

62

Number of samples positive

46

48

57

60

61

Measures of diagnostic accuracy

 Sensitivity (%)

86.3

90.2

88.2

92.2

94.1

 Specificity (%)

97.2

97.2

83.3

81.9

81.9

 PPV

0.96

0.96

0.79

0.78

0.79

 NPV

0.91

0.93

0.91

0.94

0.95

 LR+

30.8

32.2

5.3

5.1

5.2

 LR-

0.14

0.1

0.14

0.1

0.07

  1. PPV (positive predictive value); NPV (negative predictive value); LR+ (positive likelihood ratio); LR- (negative likelihood ratio)