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Table 2 Comparison of NAAT CT values (1/c) vs toxin EIA positivity

From: Can a toxin gene NAAT be used to predict toxin EIA and the severity of Clostridium difficile infection?

CT value Sensitivity (TPF) Specificity FPF PPV NPV
20 0.008 0.998 0.002 0.750 0.544
21 0.050 0.992 0.008 0.844 0.554
22 0.163 0.975 0.025 0.848 0.581
23 0.314 0.944 0.056 0.826 0.621
24 0.472 0.891 0.109 0.784 0.667
25 0.613 0.834 0.166 0.756 0.719
26 0.733 0.751 0.249 0.713 0.770
27 0.820 0.682 0.318 0.684 0.818
28 0.883 0.585 0.415 0.642 0.856
29 0.915 0.507 0.493 0.610 0.876
30 0.948 0.426 0.574 0.582 0.907
35 0.995 0.076 0.924 0.475 0.944
  1. The table shows CT values against various diagnostic measures used in the ROC analysis including sensitivity and specificity. The area under the ROC curve (AUC) was equal to AUC = 0.819, corresponding to a CT value of ≤26
  2. TPF True Positive Fraction, FPF False Positive Fraction, PPV Positive Predictive Value, NPV Negative Predictive Value