4. Are a Blood Alcohol Concentration of 256mg/dl and Minimal Signs of Impairment Reliable Indications of Alcohol Dependence?

This article describes a drink-driving scenario where a woman was apprehended for driving under the influence (DUI) with a blood alcohol concentration (BAC) of 256mg/dl¹ The correctness of this result was vigorously challenged by a medical expert witness for the defence, who was actually a specialist in alcohol diseases. Despite reanalysis to confirm the BAC as well as a DNA profile to prove the identity of the blood specimen, the woman was acquitted of the charge of drunk driving by the lower court. However, she was subsequently found guilty in the High Court of Appeals with a unanimous decision and sentenced to four weeks imprisonment.

This case report illustrates some of the problems surrounding the use of expert medical evidence by the defence to challenge the validity of the prosecution evidence based solely on a suspect's BAC. In situations such as these, an expert witness should be called by the prosecution to clarify and, if necessary, rebut medical and/or scientific opinions that might mislead the court and influence the outcome of the trial.