Fredericksburg DUI Breath and Blood Tests

There are many different ways for the alcohol content of one’s blood to be tested. In Fredericksburg, DUI breath and blood tests are two common ways for law enforcement to determine intoxication. If you face DUI charges, reach out to an experienced attorney for help building a strong defense.

Administering a Breath Test

In Fredericksburg, the breath test device is the Intox EC/IR II, which is a big machine with a set of steps that an individual must follow to administer the test correctly. One step is reading the applied consent form, which tells an individual that if they are driving in the State of Virginia, they have to consent to a blood test if there is probable cause to arrest them. Depending on which test is being used, including the Intox, there must be a 20 minute observation period before the test is administered. To administer the test, a person blows into a tube and the tube takes their breath and analyzes the number of particles to determine the person’s blood alcohol content.

To be considered valid, a breath sample must be tested on a device that is working properly,  calibrated, and on the DFS approved list.

Preliminary Road Test

A preliminary roadside breath test is completely different from the larger Intox (ER/IC II). A roadside blood test, or PBT, is only used for one purpose: determining whether or not there is probable cause for an arrest. Legally, a preliminary breath test does not have to be calibrated to be reliable. All that matters in making a probable cause determination is whether or not the officer thinks at the time the PBT is reliable.

Challenging a Breath Test

The attorney on a case is the only person that can challenge a breath test. They do this through cross-examination questions and potentially motioning to suppress the evidence based on unreliability or something similar.

DUI Blood Tests

Blood tests require a warrant based on probable cause. The blood test must be administered by somebody who meets specific requirements, like a nurse practitioner who has been trained in the necessary instruments. The blood test could occur in a variety of places, depending on the jurisdiction.


Blood tests are fairly accurate in determining BAC, but they are not accurate in determining drug impairment. Blood Tests are only able to show what is in the blood, not anything beyond that. A blood test is not able to show how impaired somebody is or what the level of impairment. It only shows the amount of intoxicants in somebody’s blood at any given time.

Refusing a Blood Test

It is rare that anyone refuses a blood test. A person is only given the blood test when there is a warrant for their blood, at which point a person would not be allowed to refuse.

Challenging a Blood Test

The steps a DUI lawyer would take to challenge the results of a blood test would be to ask cross-examination questions, potentially put on the motions to suppress and try to exclude the blood test for being improperly administered or for having other constitutional defects.

If you need help challenging a blood test or raising other defense to your DUI charges, reach out to a qualified attorney today and schedule a consultation.

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