Table 1 Results of diagnostic study based on the PTX and CRP levels

Male

Estimation

(± 95% CI)

PTX

≥ 2.07

CRP

> 3.0

PTX + CRP

Single-positive vs. double-negative

PTX + CRP

Double-positive vs. double-negative

Sensitivity

65.7%

(60.8–70.3%)

53.6%

(48.6–58.6%)

67.2%

(60.9–73.1%)

66.2%

(59.8–72.2%)

Specificity

55.0%

(52.3–57.7%)

68.0%

(65.5–70.5%)

46.9%

(44.0 – 49.9%)

70.8%

(67.3–74.0%)

PPV

30.3%

(27.2–33.4%)

33.3%

(29.7–37.1%)

21.5%

(18.6–24.6%)

41.7%

(36.7–46.9%)

NPV

84.3%

(81.7–86.7%)

83.1%

(80.8–85.3%)

86.9%

(83.9–89.5%)

86.9%

(83.9–89.5%)

Accuracy

57.5%

(55.1–59.8%)

64.7%

(62.4–67.0%)

50.5%

(47.9–53.2%)

69.7%

(39.7–57.3%)

DOR

2.33

(1.85–2.94)

2.46

(1.96–3.09)

1.81

(1.35–2.43)

4.75

(3.48–6.49)

Female

Estimation

(± 95% CI)

PTX

≥ 2.23

CRP

> 3.0

PTX + CRP

Single-positive vs. double-negative

PTX + CRP

Double-positive vs. double-negative

Sensitivity

53.8%

(47.7–59.8%)

50.2%

(44.1–56.2%)

62.2%

(54.9–69.0%)

53.5%

(45.4–61.5%)

Specificity

69.9%

(67.5–72.2%)

64.6%

(62.1–67.0%)

51.7%

(48.9–54.4%)

80.2%

(77.3–82.8%)

PPV

24.7%

(21.3–28.3%)

20.7%

(17.7–23.9%)

15.7%

(13.2–18.4%)

32.9%

(27.2–39.1%)

NPV

89.2%

(87.2–90.9%)

87.6%

(85.5–89.5%)

90.4%

(88.1–92.4%)

90.4%

(88.1–92.4%)

Accuracy

67.4%

(65.2–69.6%)

62.3%

(60.0–64.6%)

53.0%

(50.5–55.5%)

76.1%

(73.3–78.6%)

DOR

2.70

(2.08–3.51)

1.84

(1.42–2.38)

1.76

(1.29–2.40)

4.45

(3.26–6.63)