You must never drink and drive. Remember, alcohol lowers blood glucose levels, so if you are taking insulin or certain tablets for your diabetes, drinking alcohol can make you more likely to have a hypo. A hypo may look like drunkenness and if your breath smells of alcohol this could heighten suspicion.
You should avoid low-sugar (sometimes called ‘diabetic’) beers. This is because although they contain less sugar than ordinary beer, their alcohol content is higher. As little as one pint of a low-sugar beer can bring your blood alcohol level above the legal limit.
High blood glucose levels, even if there are ketones present, will not affect a breathalyser machine.
Reviewed November 2011