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Table 4 Diagnostic accuracy of procalcitonin by infection pair in 210 participants with single target infections

From: C-reactive protein and procalcitonin to discriminate between tuberculosis, Pneumocystis jirovecii pneumonia, and bacterial pneumonia in HIV-infected inpatients meeting WHO criteria for seriously ill: a prospective cohort study

Infection paira

Cut-off (μg/L)

Sensitivity% (95% CI)

Specificity% (95% CI)

PPV% (95% CI)

NPV% (95% CI)

LR+

LR-

Diagnostic odds ratio (95% CI)

TB vs. CAP

PCT ≥ 0.1

96.2 (91.4–98.8)

4.9 (1.0–13.7)

68.8 (61.6–75.4)

37.5 (8.5–75.5)

1.01 (0.95–1.08)

0.76 (0.19–3.10)

1.32 (0.34–5.21)

PCT ≥ 0.25

84.2 (76.9–90.0)

18.0 (9.4–30.0)

69.1 (61.4–76.1)

34.4 (18.6–53.2)

1.03 (0.89–1.18)

0.88 (0.45–1.70)

1.17 (0.53–2.59)

PCT ≥ 0.5

65.4 (56.7–73.4)

29.5 (18.5–42.6)

66.9 (58.1–74.9)

28.1 (17.6–40.8)

0.93 (0.76–1.14)

1.17 (0.75–1.84)

0.79 (0.41–1.52)

PCT ≥ 2

27.1 (19.7–35.5)

50.8 (37.7–63.9)

54.5 (41.8–66.9)

24.2 (17.1–32.6)

0.55 (0.38–0.80)

1.44 (1.10–1.88)

0.38 (0.20–0.72)

PCT > 10b

6.0 (2.6–11.5)

86.9 (75.8–94.2)

50.0 (24.7–5.3)

29.8 (23.2–37.1)

0.46 (0.18–1.16)

1.08 (0.97–1.20)

0.42 (0.16–1.15)

CAP vs. PJP

PCT ≥ 0.1

95.1 (86.3–99.0)

18.8 (4.0–45.6)

81.7 (70.7–89.9)

50.0 (11.8–88.2)

1.17 (0.92–1.49)

0.26 (0.06–1.180

4.46 (0.92–21.84)

PCT ≥ 0.25

82.0 (70.0–90.6)

50.0 (24.7–75.3)

86.2 (74.6–93.9)

42.1 (20.3–66.5)

1.64 (0.99–2.71)

0.36 (0.17–0.75)

4.55 (1.44–14.43)

PCT ≥ 0.5

70.5 (57.4–81.5)

56.2 (29.9–80.2)

86.0 (73.3–94.2)

33.3 (16.5–54.0)

1.61 (0.90–2.87)

0.52 (0.29–0.94)

3.07 (1.02–9.26)

PCT ≥ 2

49.2 (36.1–62.3)

81.2 (54.4–96.0)

90.9 (75.7–98.1)

29.5 (16.8–45.2)

2.62 (0.92–7.51)

0.63 (0.44–0.88)

4.19 (1.15–15.03)

PJP vs. TB

PCT ≥ 0.1

81.2 (54.4–96.0)

3.8 (1.2–8.6)

9.2 (5.0–15.3)

62.5 (24.5–91.5)

0.84 (0.67–1.07)

4.99 (1.31–18.94)

0.17 (0.04–0.71)

PCT ≥ 0.25

50.0 (24.7–75.3)

15.8 (10.0–23.1)

6.7 (2.9–12.7)

72.4 (52.8–87.3)

0.59 (0.36–0.97)

3.17 (1.69–5.93)

0.19 (0.07–0.54)

PCT ≥ 0.5

43.8 (19.8–70.1)

34.6 (26.6–43.3)

7.4 (3.0–14.7)

83.6 (71.2–92.2)

0.67 (0.38–1.18)

1.63 (1.00–2.66)

0.41 (0.15–1.14)

PCT ≥ 2

18.8 (4.0–45.6)

72.9 (64.5–80.3)

7.7 (1.6–20.9)

88.2 (80.6–93.6)

0.69 (0.24–1.99)

1.11 (0.86–1.44)

0.62 (0.18–2.17)

  1. Selected categories are based on assay guidelines developed for antibiotic use guidance in lower respiratory tract infections and sepsis (see text for details)
  2. Abbreviations: TB tuberculosis, CAP bacterial community-acquired pneumonia, PJP Pneumocystis jirovecii pneumonia, PPV positive predictive value, NPV negative predictive value, LR Likelihood ratio, CI confidence interval. aCohort prevalences: TB, 63,3% (95%CI, 56.4–69.9%); CAP, 29.0% (95% CI, 23.0–35.7%); PJP, 7.6% (95% CI, 4.4–12.1%)
  3. bAnalaysis of PCT category of > 10 was only performed in TB vs. CAP infection pairs as no PJP participants had PCT exceeding 10 μg/L
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BMC Infectious Diseases

ISSN: 1471-2334

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