Table 2.
Diagnostic accuracy of self-reported alcohol consumption compared with reference police breathalyser
| Threshold of self-reported alcohol consumption (UK units) | Total participants | Correctly positive by reference standard | Correctly negative by reference standard | Sensitivity (%) | Specificity (%) |
|---|---|---|---|---|---|
| 1 | 207 | 38/38 | 9/169 | 100.0 (90.8 to 100.0) | 5.3 (2.8 to 9.8) |
| 2 | 207 | 38/38 | 23/169 | 100.0 (90.8 to 100.0) | 13.6 (9.2 to 19.6) |
| 3 | 207 | 38/38 | 52/169 | 100.0 (90.8 to 100.0) | 30.8 (24.3 to 38.1) |
| 4 | 207 | 38/38 | 71/169 | 100.0 (90.8 to 100.0) | 42.0 (34.8 to 49.5) |
| 5 | 207 | 37/38 | 84/169 | 97.4 (86.5 to 99.5) | 49.7 (42.3 to 57.2) |
| 6 | 207 | 35/38 | 105/169 | 92.1 (79.2 to 97.3) | 62.1 (54.6 to 69.1) |
| 7 | 207 | 34/38 | 117/169 | 89.5 (75.9 to 95.8) | 69.2 (61.9 to 75.7) |
| 8 | 207 | 29/38 | 130/169 | 76.3 (60.8 to 87.0) | 76.9 (70.0 to 82.6) |
| 9 | 207 | 26/38 | 142/169 | 68.4 (52.5 to 80.9) | 84.0 (77.7 to 88.8) |
| 10 | 207 | 20/38 | 148/169 | 52.6 (37.3 to 67.5) | 87.6 (81.8 to 91.7) |
1 UK unit is equivalent to 10 mL or 8 g alcohol (total 207 participants due to missing data on alcohol consumption for 1 participant). 95% CIs are shown in parentheses.