A categorical any drinking compared to no drinking from self-reported was first compared to the empirical volume estimate and can be seen in Table 2. As the first row of the table shows, a total of 1,953 patients self-reported any drinking and 511 (26.2%) of these patients had a value of 0 for BAC. Among the 511 cases, over two-thirds reported less than 2 drinks consumed within 6 hours prior to injury and over 88% reported fewer than 6 drinks (results not shown). Of those 8,372 patients who reported no drinking, a total of 175 (2.1%) had positive values for BAC. Similarly, Table 2 also shows the any vs. no drinking relationship between self-report and from the inverted Widmark equation. Of the 1,953 who reported any drinking, a total of 156 (8.0%) did not report time from last drink to arrival at the ER and therefore the Widmark volume could not be computed. In addition, of the 8,372 who reported no drinking within 6 hours prior to the injury, the time from last drink to arrival to the ER was not available and therefore an estimated volume could not be computed.
