Table 3

Performance characteristics of WCC, CRP, and PCT

Sensitivity (%)Specificity (%)PPV (%)NPV (%)
95% confidence intervals in parentheses.
Procalcitonin >2 ng/ml94 (90–98)93 (88–98)95 (91–99)91 (86–96)
CRP >30 mg/l81 (74–88)89 (83–95)91 (86–96)76 (68–84)
WCC <4 or >15 × 109/l69 (60–78)67 (58–76)77 (69–85)56 (46–66)
Procalcitonin >2 ng/ml and CRP >30 mg/l80 (72–88)95 (91–99)96 (92–100)76 (68–84)