Table 4

Sensitivity, specificity, positive and negative predictive values (%) of admission PCT and CRP values for septic shock

Screening valueSensitivitySpecificityPPVNPV
PCT > 2 ng/ml1006269100
PCT > 5 ng/ml99787999
PCT > 10 ng/ml88848290
PCT > 20 ng/ml 83 92 90 87
CRP > 20 mg/l91626689
CRP > 30 mg/l81706982
CRP > 40 mg/l79777482
CRP > 50 mg/l 76 80 76 80
PCT > 2 ng/ml and CRP > 20 mg/l91787891
PCT > 20 ng/ml and CRP > 50 mg/l69928878
  • Optimum diagnostic cut off values derived from the ROC curve are shown in bold.

  • CRP, C reactive protein; NPV, negative predictive value; PCT, procalcitonin; PPV, positive predictive value; ROC, receiver operating characteristic.