Great Falls, VA DUI Defense Lawyers

How Breathalyzer Tests May Affect a DUI Case

When police officers arrest people on suspicion of DUI in Virginia, one of the most common tools they use to measure a driver's impairment is a breathalyzer device. Understanding how these tests work is a foundational part of building a strong defense.

A breathalyzer device will measure the concentration of alcohol in the air that a person breathes out from their lungs. It will display an estimated reading of the person's blood alcohol concentration (BAC). While breath testing is widely used, the results are not beyond question. Our legal team may look at multiple factors when evaluating the reliability of breath test results in your case.

Proper calibration and maintenance of a breathalyzer device is essential to ensure that it will produce accurate results. Records must be kept of the maintenance performed on a machine. If the device used in your case was not properly maintained or was due for calibration at the time of testing, the accuracy of the results may be questioned.

The officer administering the test must also be trained and certified to operate the equipment. Errors may occur during the testing process, such as failing to wait for the required amount of time before administering a test. These errors could affect the results, and they may provide grounds for challenging the evidence.

Blood Tests in DUI Cases

In some situations, a blood test may be used instead of a breath test, or both types of tests may be performed. Blood samples may be drawn and tested to measure a person's BAC or detect the presence of drugs in their system. While blood tests are generally considered to be more precise than breath tests, there are a variety of errors that may occur that could allow the results to be challenged.

For a blood test result to be reliable and admissible in court, the sample must be collected by a medical professional who has been certified to draw blood. Samples must be handled, transported, stored, and analyzed following specific protocols. The chain of custody, which is a record of who handled the sample at each stage, must be fully documented. Any gaps or irregularities in the chain of custody may raise questions about whether the sample that was tested is the same sample that was collected and whether contamination may have occurred at any point along the way.

Even when a sample is properly collected and transported, errors can occur during the analysis by a laboratory. Testing equipment must be calibrated correctly, analysts must follow the proper procedures, and results must be interpreted accurately. Mistakes in any of these areas can lead to inaccurate readings. If a sample is not stored correctly, fermentation may occur, or other issues may affect the accuracy of readings.

When a blood test is used to detect the presence of drugs, the interpretation of the results can become even more complex. The presence of a substance in a person's bloodstream does not automatically prove that they were impaired at the time when they were driving. Many substances will continue to be detectable in a person's blood long after the effects of a drug have subsided.

Our attorneys will review the specific substances identified by blood tests, their concentrations, and the scientific basis for any claim that you were intoxicated. We can determine the best options for challenging the results of these tests and questioning whether you have been conclusively proven to be driving while intoxicated beyond a shadow of a doubt.

Contact Our Great Falls DUI Defense Attorneys

The actions you take in the time following a DUI arrest are critical. By reaching out to an attorney, you can make sure the right steps will be taken to build a successful strategy. At Robinson Law, PLLC, we will help to shoulder your legal burden and fight for the best possible outcome in your case. Contact our Great Falls, VA DUI lawyers at 703-844-3746 to schedule your free consultation.