TABLE 3.

Performance Characteristics of Biomarkers To Predict Severe Versus Nonsevere Disease in Children With CAP

Biomarker	Thresholda	AUC (95% CI)	Sensitivity (95% CI)	Specificity (95% CI)	PPV (95% CI)	NPV (95% CI)	LR+ (95% CI)	LR− (95% CI)
Suspected CAP
WBC count	16.8	0.6 (0.54–0.67)	0.4 (0.28–0.54)	0.8 (0.77–0.84)	0.2 (0.13–0.28)	0.92 (0.89–0.94)	2.03 (1.42–2.91)	0.75 (0.6–0.92)
ANC	9.6	0.58 (0.51–0.64)	0.52 (0.38–0.65)	0.64 (0.6–0.68)	0.15 (0.1–0.2)	0.92 (0.88–0.94)	1.43 (1.09–1.87)	0.76 (0.58–0.99)
CRP	3.3	0.56 (0.48–0.63)	0.54 (0.39–0.68)	0.57 (0.48–0.63)	0.13 (0.09–0.19)	0.91 (0.87–0.94)	1.26 (0.96–1.67)	0.8 (0.59–1.1)
Procalcitonin	0.35	0.53 (0.46–0.61)	0.48 (0.34–0.62)	0.59 (0.54–0.64)	0.13 (0.09–0.19)	0.9 (0.86–0.93)	1.17 (0.86–1.58)	0.88 (0.67–1.16)
Radiographic CAP
WBC count (n = 206)	15	0.62 (0.51–0.73)	0.52 (0.31–0.73)	0.71 (0.64–0.78)	0.19 (0.1–0.3)	0.92 (0.87–0.96)	1.8 (1.15–2.83)	0.67 (0.43–1.04)
ANC (n = 206)	11.2	0.63 (0.52–0.74)	0.57 (0.35–0.77)	0.69 (0.62–0.76)	0.19 (0.1–0.3)	0.93 (0.87–0.96)	1.81 (1.19–2.76)	0.63 (0.39–1.02)
CRP (n = 200)	6.23	0.59 (0.47–0.7)	0.57 (0.34–0.78)	0.60 (0.53–0.68)	0.15 (0.08–0.24)	0.92 (0.86–0.96)	1.4 (0.95–2.2)	0.71 (0.43–1.18)
Procalcitonin (n = 205)	0.52	0.64 (0.53–0.76)	0.62 (0.38–0.82)	0.67 (0.6–0.74)	0.18 (0.1–0.28)	0.94 (0.88–0.97)	1.87 (1.26–2.77)	0.57 (0.33–0.99)

LR+, positive likelihood ratio; LR−, negative likelihood ratio.

^aEmpirical cut point estimation at the point closest to perfect sensitivity and specificity (ie, upper left-hand corner of the ROC curve).