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Call 24/7 for Jail Release or schedule a Free Consultation:

(512) 599-9000

Breath testing

If you are charged with DWI in the state of Texas, you need to take it quite seriously because it can have some severe consequences. It is essential to know all the facts related to your case in order to defend yourself better. Just because you fail a breath test doesn’t mean that you are automatically guilty. Many factors can cause a breathalyzer test to produce false positive results. You need to be aware of these issues and challenge the test if you have doubts.

The Slope Detector

One of the reasons that a breath test might be unreliable is due to the slope detector. Newer breathalyzers have an infrared slope detection system that can distinguish a mouth sample from a lung sample. These breathalyzer tests estimate that the first two-thirds of the sample is not a fair concentration and are, therefore, discarded. It is crucial to know the model of breathalyzer that was used to conduct your breath test. You can argue that your test results are not reliable if your test was performed on a model that does not have the slope detector built in.

The Acceptable Margin of Error

In the state of Texas, law enforcement officials use a machine called the Intoxilyzer 5000 which assumes that the average person’s temperature is 98.6 degrees. If your test was done when your temperature is above that threshold, it could affect your results. Moreover, if the breathalyzer was not cleaned properly, there can be contamination from one test to another, which can modify your test results. The acceptable margin of error for the Intoxilyzer is .01, which is plus or minus 10% of the reading. This implies that you could test as having a BAC of .08 when it is actually lower.

The .08 Reference Solution and the Partition Ratio

A breathalyzer doesn’t measure the BAC directly. Rather, it estimates it. When it computes the test results, the breathalyzer has to multiply the BAC measurement by something called the “partition ratio” or “blood-to-breath ratio.” Most breathalyzers assume that this ratio is standard for everyone. However, factors like sex, body weight, breathing patterns, hematocrit levels, and body temperature can have an impact on the results. We cannot assume that the partition ratio used was correct by the breathalyzer. It is possible that it may have led to a false positive in your case.

If you failed a breathalyzer test, you can argue against the reliability of the test results. Many factors can affect the reliability of breath testing. Before you stand trial for your DWI arrest, it is essential to educate yourself on all of these possible issues. A professional attorney will build your defense based on a thorough investigation of the results presented. If you need a DWI/DUI lawyer to build your winning defense, contact Stephen T. Bowling today.

© 2019 Steve Bowling Law, PLLC
10.0Stephen Bowling 10.0David Michael Thomas

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Austin, Texas 78701

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