A breath test cannot account for the presence of drugs in your system. If a person is accused of DUI and the officer suspects that it is a drug-related offense, they will ask for a urine sample. However, in Florida they very rarely test urine to determine the quantity of the drug in the urine; therefore, just the presence will register.
When presenting a case to a jury a prosecutor will not be able to tell a jury how much of that drug was in the system or when it was entered into the system. And drugs remain in your system far longer than their intoxicating effects.
One of the best defenses to a drug case is the fact that it is the State’s burden to prove the case beyond a reasonable doubt. And without being able to tell a jury how much drugs or when they were taken are in a person’s system that’s a very difficult hurdle to overcome.