Diagnostic indices of mild TBI risk score categorized by risk category
| Risk factors | CT positive | CT negative | Sensitivity (%) | Specificity (%) | PPV (%) | NPV (%) | LR+ |
| Low risk | 38 | 109 | 8.2 | 79.7 | 25.9 | 50.4 | 0.4 |
| Moderate risk | 263 | 87 | 57.1 | 83.8 | 75.1 | 69.5 | 3.5 |
| High risk | 132 | 2 | 28.6 | 99.6 | 98.5 | 62.0 | 77.3 |
Low risk, mild TBI score <3 points; moderate risk, mild TBI score 3–6 points; high risk, mild TBI score ≥7 points.
LR+, likelihood ratio positive; 0.89 and 95% CI 0.87 to 0.91; NPV, negative predictive value; PPV, positive predictive value; TBI, traumatic brain injury.