In Florida, most DUI (driving under the influence of alcohol or drugs) cases involve the police requesting the defendant take a breathalyzer test at the jail. This test is normally offered only after the police make the DUI arrest. Therefore, if the defendant has a low score on the breathalyzer, or even a 0.00 result, the defendant is still arrested for DUI. In many cases, the police will then request a urine or blood sample to test for other substances. The police do not admit error after making an arrest, and once the police effect the DUI arrest, there is no going back.
There are times when the police can draw blood and send the blood to the lab for testing of blood alcohol content. The police are not allowed to obtain a blood draw when a breath test is viable and reasonable, as in most DUI cases in Florida. However, the DUI suspect can request one, and there are other situations where the blood draw is permissible. This often comes up in DUI cases that involved serious accidents.
In Florida, when a person is involved in a serious accident and has a serious injury that requires a trip to the hospital, it may not be practical to obtain a breath sample from the DUI suspect. In those cases, the police may be allowed to obtain a blood sample at the hospital for testing. The police cannot do it in any situation where there is an accident and the suspect is taken to the hospital with serious injuries. The police need reasonable and sufficient evidence that the suspect was impaired while driving. However, it seems as if that standard is pretty low when serious accidents are involved.