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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)