Table 4.
Subgroup analysis in children (age ≤ 18) of the diagnostic performance of the host-protein signature, CRP, IL-6, and PCT
| Index test | Cutoffs | Sensitivity % (95% CI) | Specificity % (95% CI) | PPV % (95% CI) | NPV % (95% CI) |
|---|---|---|---|---|---|
| Host-protein signature |
< 35 viral > 65 bacterial |
95.2 (88.5–100) | 94.1 (90.1–98.1) | 83.3 (72.4–94.3) | 98.5 (94.2–100) |
| PCT | 0.5 ng/mL | 59.6 (45.8–73.4) | 82.8 (76.7–88.9) | 54.4 (41.1–67.7) | 85.6 (79.3–91.9) |
| 1 ng/mL | 51.9 (37.9–66.0) | 92.7 (88.5–96.9) | 71.1 (55.9–86.2) | 84.8 (80.8–88.9) | |
| 2 ng/mL | 50.0 (35.9–64.1) | 97.4 (94.8–99.9) | 86.7 (73.8–99.6) | 85.0 (82.1–87.8) | |
| CRP | 20 mg/L | 96.2 (90.7–100) | 56.3 (48.3–64.3) | 43.1 (34.0–52.3) | 97.7 (79.5–100) |
| 40 mg/L | 84.6 (74.5–94.8) | 77.5 (70.7–84.2) | 56.4 (45.2–67.7) | 93.6 (84.9–100) | |
| 80 mg/L | 63.5 (49.9–77.0) | 95.4 (92.0–98.8) | 82.5 (70.2–94.8) | 88.3 (85.0–91.7) | |
| IL-6 | 25 pg/mL | 59.6 (45.8–73.4) | 55.0 (46.9–63.0) | 31.3 (22.0–40.6) | 79.8 (66.7–92.9) |
| 50 pg/mL | 44.2 (30.3–58.2) | 82.1 (75.9–88.3) | 46.0 (31.7–60.3) | 81.0 (74.9–87.1) | |
| 100 pg/mL | 25.0 (12.8–37.2) | 92.7 (88.5–96.9) | 54.2 (32.7–75.7) | 78.2 (74.2–82.3) |
Diagnostic performance was evaluated by comparing the comparator method outcome with the outcome classified by the index test, (nB = 52, nV = 151). The host signature assigned equivocal results to 12.3% of children
nB number of patients with unanimous expert panel diagnosis of bacterial infection, nV number of patients with unanimous expert panel diagnosis of viral infection