Skip to main content

Table 2 PCT and CRP versus emergency physician judgement in diagnosing bacterial/parasitic infection

From: Serum procalcitonin measurement as diagnostic and prognostic marker in febrile adult patients presenting to the emergency department

Test and cutoff Sensitivity (95% CI) Specificity (95% CI) PPV (95% CI) NPV (95% CI) Accuracy (95% CI)
CRP      
   ≥ 5 mg/l 0.96 (0.91–0.98) 0.16 (0.09–0.26) 0.71 (0.65–0.77) 0.63 (0.41–0.81) 0.71 (0.64–0.76)
   ≥40 mg/l 0.76 (0.69–0.82)* 0.62 (0.51–0.72) 0.81 (0.74–0.87) 0.54 (0.44–0.64)* 0.71 (0.65–0.77)
   ≥100 mg/l 0.54 (0.46–0.62) 0.90 (0.82–0.95) 0.93 (0.85–0.96) 0.47 (0.39–0.56) 0.65 (0.59–0.71)
PCT      
   ≥0.1 μg/l 0.90 (0.85–0.94) 0.32 (0.22–0.43) 0.74 (0.68–0.80) 0.60 (0.47–0.74) 0.72 (0.66–0.77)
   ≥0.2 μg/l 0.77 (0.70–0.82)* 0.59 (0.48–0.70) 0.80 (0.74–0.86) 0.54 (0.43–0.64)* 0.71 (0.65–0.77)
   ≥0.5 μg/l 0.63 (0.55–0.70) 0.79 (0.68–0.87) 0.87 (0.80–0.92) 0.49 (0.40–0.58) 0.68 (0.62–0.73)
   ≥2 μg/l 0.36 (0.30–0.44) 0.93 (0.85–0.97) 0.92 (0.83–0.97) 0.40 (0.33–0.47) 0.54 (0.48–0.60)
   ≥5 μg/l 0.23 (0.17–0.30) 0.99 (0.93–1.00) 0.97 (0.87–0.99) 0.37 (0.30–0.44) 0.46 (0.40–0.53)
Emergency physician 0.85 (0.79–0.90) 0.57 (0.45–0.67) 0.81 (0.75–0.86) 0.63 (0.51–0.74) 0.76 (0.70–0.81)
  1. Shown is a comparison of performance of procalcitonin (PCT) and C-reactive protein (CRP) with emergency physician for the diagnosis of bacterial/parasitic infection, with the 'gold standard' being experts diagnosis. *P < 0.05, versus emergency physician. CI, confidence interval; NPV, negative predictive value; PPV, positive predictive value.