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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