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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 geneCutoff Ct value (cycles)% (95% confidence interval)AUC
SensitivitySpecificityPPVNPV
KPC≤38.083.3 (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)*
≤35.083.3 (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≤38.0100.0 (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)*
≤35.050.0 (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≤38.0100.0 (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)*
≤35.093.33 (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