Published on:

Why Portable Breath Test Results Cannot be Admitted as Evidence to Prosecute DUI Charges

Portable Breath Test Unit

A Portable Breath Test (PBT) Unit is a hand-held mobile device, used by police in Arizona DUI field stops. The PBT is a preliminary DUI breath test tool used to test a person’s Blood Alcohol Content or BAC. The purpose of the PBT is simply to distinguish if a driver is under the influence of alcohol or drugs. It an early screening and detection tool only. If used to obtain a reading, it must be followed up with use of a formal breathalyzer test for alcohol, or chemical tests for drug impairment determination. Arizona prohibits use of a PBT as admissible evidence in court.

Why PBTs are not Admissible in Scottsdale AZ Courts

PBTs are not admissible as sole DUI breath test evidence because the Portable Breath Test Units are calibrated, or routinely maintained like the official breath test machine or the Intoxilyzer 8000 Device. There are a number of tests the police can use as evidence to charge or arrest a person for DUI if they have reasonable suspicion to believe a person is driving impaired to the slightest degree do to drugs or alcohol. The breathalyzer machine cannot test for drug consumption or ingestion. So if the Arizona highway patrol or local police have pulled you over to conduct a DUI investigation, and are not sure if you are “impaired to the slightest degree” based on alcohol, they may first use a PBT to test your blood alcohol content level.

When PBT Readings are Positive 

If the initial PBT results are positive for alcohol in your system, the police will request a second breath test or official breath test. This breath test is conducted with an official calibrated and maintained machine. If the BAC is positive, and the police determine that you were driving “impaired to the slightest degree” or test over .08%, they will make a DUI arrest. Only the results of the second or official blood test can be used. The PBT results are not admissible as evidence.

When PBT Results are Negative

If the initial PBT is negative for alcohol, the police will request DUI blood or urine sample to test for drug DUI. Some police patrols have specialized phlebotomy training and credentials and resources required to administer the test in the field. If not, they will transport you to another location to obtain a DUI blood test, or other chemical test. You should always request a second sample be collected for use in your defense.