Breath Test vs. Blood Test

Written by Reynolds Defense Firm

On July 25, 2022

If you are pulled over in Oregon and arrested for suspicion of DUII, you will likely be taken to a police station to test your blood alcohol content (BAC). And you’ve likely heard of a “breath test” and a “blood test” as methods for testing a person’s BAC, but what’s the difference between the two?

Breathalyzer vs. A Blood Test

There are a few differences between these two tests. The most obvious difference is the process of the test. For a breathalyzer, you simply blow a breath sample into a hand-held mouthpiece attached to a machine. A blood test is done with a blood draw.

Oregon police officers do not need to get a search warrant to get a breath sample on a breathalyzer machine, because of the implied consent law. They are required, however, to get a warrant before they take blood samples due to the fact that the process is more invasive.

If a person refuses to provide a breath test, the officer can apply for a search warrant to obtain a blood draw. Additionally, if there was an accident and the driver is taken to the hospital, and DUII is suspected, a breath test is not an option. At that point, the only other option for an officer is a blood test.

Breath Test

breathalyzer test is a test that is performed at the police station. For this test, you will be asked to blow into a tube that is attached to a machine. The machine analyzes your breath sample to test for alcohol molecules and produces a reading of your BAC.

Blood Test

A blood test involves submitting a blood draw. Most commonly the blood is drawn at the police station by a mobile blood draw technician or someone employed by the police department to draw blood, possibly in a jail cell or a room specifically designed for blood draws. A blood test may also be performed at a hospital by a phlebotomist if you are hospitalized for medical treatment after an alleged DUI incident. Once your sample is drawn, it will be given to the officer and taken back to the police station to be transported to the crime lab for analysis.

Breathalyzer vs. Blood Test Accuracy

The chemistry of how a breathalyzer works is sophisticated and complex. Basically, the process involves measuring the oxidation of the alcohol in your breath. The alcohol in your breath can be indicative of the alcohol in your blood because the alcohol dissolved in your blood is proportionate to the alcohol in your breath.

Breath tests have a larger margin for error because they can be skewed by diet, health issues, mouthwash, mints, or other products that contain alcohol. Blood tests generally produce more accurate results than breathalyzers because blood tests are less impacted by external factors. However, blood and breath tests typically produce very close results, being only marginally different.

Why do police use breath tests if they can be skewed?

Breath tests are less invasive than blood tests and easier to administer. They also produce results immediately rather than waiting for laboratory results. And today, breathalyzers are very accurate if they are maintained, calibrated, and used according to the procedure.

Call Reynolds Defense Firm

If you or someone you care about is facing a DUI charge in Oregon, call Reynolds Defense Firm at 503-496-7558.  We have a team of DUI attorneys with over 80 years of combined experience who are here to help. Our firm believes everyone who calls deserves a free consultation, so please do not hesitate to contact us.  The Reynolds Defense Firm team is happy to answer all of your questions and will point you and your family in the right direction so you can sleep better at night.

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