Performance of the Low Risk Ankle Rule at intervention sites
| Variable | % (95% CI)* | |||||
|---|---|---|---|---|---|---|
| Phase 1, n = 264 | Phases 2–3, n = 430 | Phases 1–3, n = 694 | ||||
| High-risk injury | Low-risk injury | High-risk injury | Low-risk injury | High-risk injury | Low-risk injury | |
| Low-risk examination, no. | 1 | 136 | 0 | 213 | 1 | 349 |
| High-risk examination, no. | 19 | 108 | 29 | 188 | 48 | 296 |
| Sensitivity | 95.0 (73.1 to 99.7) | 100.0 (85.4 to 100) | 98.0 (87.7 to 99.9) | |||
| Specificity | 55.7 (49.1 to 69.1) | 53.1 (48.1 to 58.1) | 54.1 (50.2 to 58.0) | |||
| Negative predictive value | 99.3 (95.4 to 100.0) | 100.0 (97.5 to 100.0) | 99.7 (98.2 to 100.0) | |||
| Positive predictive value | 15.0 (9.5 to 22.6) | 12.0 (8.3 to 16.9) | 14.0 (10.6 to 19.2) | |||
| Likelihood ratio positive | 2.1 (1.8 to 2.5) | 1.9 (1.7 to 2.1) | 2.1 (1.9 to 2.3) | |||
| Likelihood ratio negative | 0.09 (0.01 to 0.6) | 0 | 0.04 (0.01 to 0.3) | |||
Note: CI = confidence interval.
↵* Unless stated otherwise.