Chemical Test Overview

Blood, Breath or Urine

Chemical testing in DUI cases involves the testing of bodily fluids – blood, breath, or urine. In California when you are accused of driving under the influence of alcohol, you have the right to take either a breath or a blood test. Where driving under the influence of drugs is suspected, your chemical test choices will be blood or urine. (There is no right to a urine test in DUI / DWI case in California)

Although chemical testing might be accurate enough to determine blood or breath alcohol content (BAC)at the time of testing, it is not conclusive evidence of BAC at the time of driving. It is not illegal to be above the .08 limit while at the police station - the crime is for driving under the influence. This is a critical point because alcohol levels change over time.

Testing for alcohol or drugs (DUI drugs) is not always accurate. There are challenges to roadside breath tests, police station breath tests, blood tests, and urine tests.

Testing in DUI drugs cases is even more challenging than testing for alcohol levels in a drunk driving case. Drug testing involves the search for metabolites in the blood or urine - not the drug itself.

Because there is no legal limit in drug cases and the time which any one drug might stay in your system is different it is very difficult for the prosecution to demonstrate that a person was impaired at the time of driving.