Table 5.
Subgroup analysis in adults (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 |
92.6 (86.8–98.4) | 95.7 (86.6–100) | 98.7 (96.1–100) | 78.6 (69.1–88.1) |
| PCT | 0.5 ng/mL | 31.0 (21.1–41.0) | 95.8 (87.2–100) | 96.4 (89.1–100) | 27.7 (19.3–36.1) |
| 1 ng/mL | 26.4 (17.0–35.9) | 95.8 (87.2–100) | 95.8 (87.2–100) | 26.4 (18.3–34.6) | |
| 2 ng/mL | 18.4 (10.1–26.7) | 100 (100–100) | 100 (100–100) | 25.3 (17.6–33.0) | |
| CRP | 20 mg/L | 97.7 (94.5–100) | 62.5 (41.6–83.4) | 90.4 (84.4–96.5) | 88.2 (53.7–100) |
| 40 mg/L | 94.3 (89.3–99.2) | 79.2 (61.6–96.7) | 94.3 (89.3–99.2) | 79.2 (61.6–96.7) | |
| 80 mg/L | 85.1 (77.4–92.7) | 100 (100–100) | 100 (100–100) | 64.9 (55.3–74.4) | |
| IL-6 | 25 pg/mL | 49.4 (38.7–60.1) | 91.7 (79.7–100) | 95.6 (89.3–100) | 33.3 (23.7–43.0) |
| 50 pg/mL | 37.9 (27.5–48.3) | 100 (100–100) | 100 (100–100) | 30.8 (22.1–39.5) | |
| 100 pg/mL | 25.3 (16.0–34.6) | 100 (100–100) | 100 (100–100) | 27.0 (18.9–35.0) |
Diagnostic performance was evaluated by comparing the comparator method outcome with the outcome classified by the index test, (nB = 87, nV = 24). The host signature assigned equivocal results to 6.3% of adults
nB number of patients with unanimous expert panel diagnosis of bacterial infection, nV number of patients with unanimous expert panel diagnosis of viral infection