State Administered DWI Breath Test
There are two types of breath tests that may be administered in a driving while intoxicated (DWI) case: a portable breath test and a state-administered DWI breath test. Breath tests are used to determine a driver’s blood alcohol content (BAC). The legal limit in the United States is .08 percent.Often used roadside, a portable breath test can determine whether a drunk-driving arrest can be made. The numerical results of this test are generally inadmissible in court because of its inaccuracy—the results may only be used to confirm if the driver was positive or negative for alcohol.
The state-administered breath test is used for the official BAC results. You may have heard this referred to as a breathalyzer test. This machine has an error margin of +/-.02. In a DWI case, two tests must be administered, with the lowest test result being used by the police. Due to the margin of error, the two tests may not vary more than .02 grams.
If you refuse to take the state-administered breath test, you may face harsher penalties than if you took the test and failed. In most states, your license may be automatically suspended if you refuse to take a chemical test.
The breath test machine does not directly measure your blood alcohol content—rather, it estimates BAC by measuring how much alcohol is on your breath. This can be problematic, as the machine assumes that you have a 2100:1 blood to breath ratio, meaning that for every 2100 parts of alcohol in the blood, there is 1 part in the breath sample. However, this ratio can vary widely and someone with a lower ratio would have a higher breath test reading.
Mouth alcohol may also have an effect on the breathalyzer. Although the machine assumes it is testing air from the lungs, the alcohol may actually be coming from the mouth. This alcohol is not absorbed into the blood and may inflate the results of the test.
Causes of mouth alcohol may include burping and vomiting. Medical conditions such as acid reflux may also cause alcohol to rise into the throat, which are then breathed into the breathalyzer. Gum, mouthwash, and mints may also contribute to mouth alcohol.
Contact an experienced DWI defense lawyer to discuss your state-administered breath test results.Your attorney can investigate your results to determine whether there was an error with the machine or the administration of the test.
