Blood alcohol concentration determined from urine samples as a practical equivalent or alternative to blood and breath alcohol tests.

The value of urine tests for determining an equivalent blood alcohol concentration in driving under the influence (DUI) enforcement cases is reviewed from a historical, theoretical, and practical perspective. The limits of precision and accuracy that can be ascribed to urine alcohol results are demonstrated through an evaluation of actual case results wherein both a first void and a subsequent urine sample were analyzed and converted to an equivalent blood alcohol concentration (BAC) using a urine to blood conversion factor of 1.3:1.