Table 3.
Diagnostic performance of host-protein signature compared to prediction rules
| Index test | Total accuracy % (95% CI) | Sensitivity % (95% CI) | Specificity % (95% CI) | PPV % (95% CI) | NPV % (95% CI) |
|---|---|---|---|---|---|
| Host-protein signature | 94.0 (91.2–96.8) | 93.5 (89.1–97.9) | 94.3 (90.7–98.0) | 92.7 (88.1–97.4) | 94.9 (91.3–98.6) |
| CRP < 20 mg/L and PCT < 0.5 ng/mL | 71.3 (66.3–76.4) | 97.1 (94.3–99.9) | 50.9 (43.4–58.3) | 61.1 (54.6–67.6) | 95.7 (76.6–100) |
| CRP > 80 mg/L or PCT > 2 ng/mL | 88.5 (85.0–92.1) | 81.3 (74.7–87.9) | 94.3 (90.8–97.8) | 91.9 (87.0–96.8) | 86.4 (83.0–89.7) |
| Lab-score ≥ 3 pointsa | 83.1 (79.0–87.3) | 73.4 (65.9–80.8) | 90.9 (86.5–95.2) | 86.4 (80.2–92.7) | 81.1 (77.1–85.2) |
| Thayyil et al. [34] | |||||
| CRP ≥ 50 mg/L and PCT ≥ 2 ng/mL and WBC ≥ 15,000/mm3 | 60.6 (55.2–66.1) | 11.6 (6.2–17.0) | 100 (100–100) | 100 (100–100) | 58.5 (54.9–62.2) |
| Olaciregui et al. [35] | |||||
| CRP ≥ 30 mg/L or PCT ≥ 0.5 ng/mL or WBC ≥ 15,000/mm3 | 73.9 (69.0–78.8) | 97.1 (94.3–99.9) | 55.2 (47.7–62.7) | 63.5 (57.0–70.1) | 96.0 (79.0–100) |
For all of the index tests, diagnostic performance was evaluated by comparing the expert panel diagnosis (nB = 139, nV = 175) with the outcome classified by the index test. Predefined cutoffs were applied as indicated. The host-protein signature assigned equivocal results to 10.2% of patients
PPV positive predictive value, NPV negative predictive value, nB number of patients with unanimous expert panel diagnosis of bacterial infection, nV number of patients with unanimous expert panel diagnosis of viral infection
aThe Lab-score incorporates PCT and CRP, weighed differently according to their level, and urinary dipstick results: CRP (< 40 mg/L: 0 points; 40–99 mg/L: 2 points; ≥ 100 mg/L: 4 points), PCT (< 0.5 ng/mL: 0 points; ≥ 0.5–1.99 ng/mL: 2 points; ≥ 2.0 ng/mL: 4 points), and positive urine dipstick (1 point). [19]