The Three Types of DUI Tests

While the breathalyzer is popular because it allows a police officer to administer the test at the scene of the traffic stop, this is not necessarily the most accurate in determining a person's BAC. This portable machine lives up to its name in that it is nothing more than a tube in which a suspect breathes or blows air into. The breathalyzer can quickly give a measurement of the suspect's BAC based upon the alcohol in a single breath. However, this machine can on occasion give false readings, making it the most unreliable of the three. For example, legal substances like cough syrup contain some alcohol and may give off a reading.

The two other tests that establish a person's BAC are blood and urine tests. These are simply analyses of samples taken from or given by the suspect at the police station. Of the three, a blood test is regarded as the most accurate. Therefore, a urine test is often used as a last ditch effort. But, the urine and blood tests also have one more advantage over the breathalyzer: they can be used to test for the presence of other drugs in the system, while the breathalyzer cannot.