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Table 4 ROC curve analysis of the Carba-R assay stratified by carbapenemase gene and the cutoff Ct value

From: Diagnostic performance of the Xpert Carba-R assay for active surveillance of rectal carbapenemase-producing organisms in intensive care unit patients

Carbapenemase gene

Cutoff Ct value (cycles)

% (95% confidence interval)

AUC

Sensitivity

Specificity

PPV

NPV

KPC

≤38.0

83.3 (51.6–97.9)

99.8 (98.6–100.0)

90.9 (58.7–99.8)

99.5 (98.2–99.9)

0.92 (0.88–0.94)*

≤35.0

83.3 (51.6–97.9)

100.0 (99.1–100.0)

100.0 (69.2–100.0)

99.5 (98.2–99.9)

0.92 (0.89–0.94)*

IMP-1

≤38.0

100.0 (15.8–100.0)

97.5 (95.5–98.8)

16.7 (2.1–48.4)

100.0 (99.1–100.0)

0.99 (0.97–1.00)*

≤35.0

50.0 (1.3–98.7)

99.3 (97.8–99.8)

25.0 (0.6–80.6)

99.8 (98.6–100.0)

0.75 (0.70–0.79)

Total

≤38.0

100.0 (78.2–100.0)

96.7 (94.4–98.2)

53.6 (33.9–72.5)

100.0 (99.0–100.0)

0.98 (0.97–0.99)*

≤35.0

93.33 (68.1–99.8)

99.2 (97.8–99.8)

82.4 (56.6–96.2)

99.7 (98.6–100.0)

0.96 (0.94–0.98)*

  1. *P < 0.0001, Abbreviations: PPV positive predictive value, NPV negative predictive value, AUC area under the ROC curve