Appellant was convicted of felony drunk driving offenses. On appeal, he argued that the trial court erred when it prevented him from cross-examining the criminalist about the partition ratio used to convert a urine-alcohol measurement into a blood-alcohol equivalent. The appellate court here held that the trial court prejudicially erred when it precluded cross-examination on the subject, as it was relevant evidence in a prosecution for drunk driving, and reversal was therefore required.