Table 2 Each evaluated guideline’s theoretical performance in detecting intracranial hemorrhage and its theoretical effect on CT rate
Guideline | Sensitivity % | Specificity % | NPV % | PPV % | CT rate % | ∆ CT rate a % |
|---|---|---|---|---|---|---|
a-NOC (95% CI) | 97.1 (90.1–99.7) | 3.4 (2.4–4.5) | 95.6 (84.2–98.9) | 5.2 (5–5.4) | 96.7 (95.6–97.6) | +  35.7 (P < 0.001) |
a-CCHR (95% CI) | 87.1 (77–94) | 35.7 (33.1–38.9) | 98.1 (96.5–99) | 6.9 (6.3–7.6) | 65.5 (62.9–68) | +  4.5 (P = 0.015) |
NEXUS II (95% CI) | 85.7 (75.3–92.3) | 35.2 (32.6–37.9) | 97.8 (96.2–98.8) | 6.7 (6.1–7.4) | 65.9 (63.3–68.4) | +  4.9 (P = 0.008) |
NICE (95% CI) | 75.7 (63.1–83.5) | 58 (55–60.5) | 97.8 (96.7–98.6) | 8.9 (7.8–10.2) | 44 (41.3–46.7) | - 17 (P < 0.001) |
SNC (95% CI) | 88.6 (78.7–94.9) | 50 (47.3–52.8) | 98.8 (97.7–99.4) | 8.8 (8–9.7) | 52 (49.3–54.7) | - 9 (P < 0.001) |