Breath and Blood Test Defenses
Facing a DWI charge in Texas can be overwhelming, especially when breath and blood test results are used as primary evidence against you. However, it’s important to know that these tests are not infallible. There are several defense strategies that can be employed to challenge their accuracy and reliability, including issues related to calibration, contamination, and chain of custody errors.
Calibration Issues
Breathalyzer devices, such as the Intoxilyzer 9000 used in Texas, must be properly calibrated and maintained to provide accurate readings. Regular maintenance and calibration checks are mandated by Texas law to ensure the device’s accuracy. If these devices are not calibrated correctly, they can produce erroneous results. For instance, an improperly calibrated machine might display a higher blood alcohol concentration (BAC) than is accurate, leading to unjust charges. Challenging the calibration records and maintenance history of the breathalyzer can be a potent defense strategy.
Contamination
Blood tests are generally considered more accurate than breath tests; however, they are not immune to errors. Contamination can occur at various stages, from the collection of the blood sample to its analysis in the laboratory. For example, if the blood sample is not stored properly, it can ferment, leading to an increase in alcohol content and a falsely elevated BAC result. Additionally, using alcohol-based disinfectants during the blood draw can contaminate the sample. Scrutinizing the procedures followed during the collection, storage, and analysis of the blood sample can reveal potential contamination issues and/or chain of custody issues that may be used in your defense.
Chain of Custody Errors
The chain of custody refers to the documented process that outlines the collection, transfer, storage, and analysis of evidence. In DWI cases, maintaining an unbroken chain of custody for blood samples is crucial to ensure their integrity. Any gaps or discrepancies in this chain can raise doubts about the authenticity and reliability of the evidence. For instance, if there is uncertainty about who handled the sample or how it was stored at any point, it could have been tampered with or contaminated. Highlighting chain of custody errors can be an effective way to challenge the admissibility of the blood test results.
Additional Considerations
Beyond calibration, contamination, and chain of custody issues, other factors can influence the accuracy of breath and blood tests:
- Medical Conditions: Certain medical conditions, such as acid reflux, diabetes, or ketosis, can affect breathalyzer results, leading to falsely high BAC readings.
- Improper Administration: The accuracy of both breath and blood tests heavily depends on proper administration. Errors made by the administering officer or technician, such as failing to observe the mandatory waiting period before a breath test or using incorrect procedures during a blood draw, can compromise the results.
- Machine Malfunctions: Mechanical issues or software malfunctions in testing devices can lead to inaccurate readings.
Challenging the results of breath and blood tests requires a thorough understanding of the testing procedures and potential pitfalls. An experienced DWI defense attorney can examine the specifics of your case, identify any weaknesses in the prosecution’s evidence, and develop a robust defense strategy tailored to your situation.
If you’re facing DWI charges, it’s imperative to act swiftly and speak with a criminal defense attorney.
