Positive predictive value of a traumatic brain injury (TBI), based on the high, medium and low level of certainty, in emergency departments and a shock trauma centre among a sample of medical records uniquely assigned International Classification of Disease, Tenth Revision, Clinical Modification code S09.90 (‘unspecified injury of head’), by state*
| Level of certainty | Maryland N=352 | Kentucky N=385 | Colorado N=382 | Massachusetts N=384 | ||||
| Count | Percentage | Count | Percentage | Count | Percentage | Count | Percentage | |
| High | 130 | 37.0 | 103 | 26.8 | 156 | 40.8 | 87 | 22.7 |
| Medium | 34 | 9.7 | 39 | 10.1 | 43 | 11.3 | 50 | 13.0 |
| Low | 82 | 23.4 | 90 | 23.4 | 74 | 19.4 | 146 | 38.0 |
| High +medium levels | 164 | 46.7 | 142 | 36.9 | 199 | 52.1 | 137 | 35.7 |
| All levels of certainty | 246 | 70.1 | 232 | 60.3 | 273 | 71.5 | 282 | 73.7 |
| No signs/symptoms of TBI | 105 | 29.9 | 153 | 39.7 | 109 | 28.5 | 103 | 26.3 |
*Due to the extent of methodological differences between the states, authors are unable to account for the variation in results seen across states. For this reason, state-specific results should not be compared.