Table 3 Diagnostic performance of lipocalin-2 and syndecan-4 biomarkers compared to white blood cell count and C reactive protein at time of enrollment in 110 children hospitalized for radiologically confirmed community-acquired pneumonia to predict infections and severity of disease, and odds ratio and 95 % confidence interval according to the biomarker cut-off with the highest sensitivity and specificity

LIP2

≥1,633

71.2 %

62.7 %

68.9 %

65.3 %

0.62 (0.51-0.73)

4.26 (1.76-10.3)

SYN4^a

≤1.78

28.8 %

80.4 %

63.0 %

49.4 %

0.50 (0.39-0.61)

1.78 (0.62-5.15)

WBC

≥13,500

63.8 %

68.6 %

69.8 %

62.5 %

0.66 (0.55-0.76)

3.91 (1.50-10.2)

CRP

≥12.3

58.6 %

68.6 %

68.0 %

59.3 %

0.63 (0.52-0.74)

2.59 (1.03-6.54)

LIP2

≥1,633

58.1 %

50.0 %

70.5 %

36.7 %

0.51 (0.40-0.63)

1.21 (0.49-2.99)

SYN44

≥7.25

31.1 %

86.1 %

82.1 %

37.8 %

0.54 (0.42-0.65)

5.54 (1.56-19.7)

WBC

≥10,300

74.0 %

38.9 %

71.1 %

42.4 %

0.57 (0.46-0.69)

1.90 (0.72-4.97)

CRP

≥7.4

64.4 %

69.4 %

81.0 %

49.0 %

0.65 (0.53-0.76)

3.35 (1.30-8.63)

LIP2

≥896

87.5 %

28.7 %

17.3 %

93.1 %

0.50 (0.37-0.64)

3.50 (0.61-20.1)

SYN4^a

≤5.64

81.2 %

37.2 %

18.1 %

92.1 %

0.54 (0.40-0.69)

7.16 (1.20-42.6)

WBC^a

≤19,710

93.7 %

28.0 %

18.3 %

96.3 %

0.56 (0.42-0.70)

8.02 (0.75-85.1)

CRP^a

≤5.2

75.0 %

64.5 %

26.7 %

93.7 %

0.67 (0.53-0.80)

5.95 (1.44-24.7)

LIP2

≥783

83.3 %

50.0 %

84.3 %

48.1 %

0.64 (0.50-0.78)

5.45 (1.83-16.2)

SYN4^a

≤5.83

71.4 %

50.0 %

82.2 %

35.1 %

0.58 (0.44-0.71)

4.37 (1.40-13.6)

WBC

≥11,170

73.5 %

69.2 %

88.4 %

45.0 %

0.71 (0.59-0.83)

8.34 (2.61-26.7)

CRP

≥4.56

67.5 %

61.5 %

84.8 %

37.2 %

0.65 (0.51-0.79)

2.72 (0.98-7.57)