Can You Challenge Blood Alcohol Test Results in Missouri?

In Missouri, a DUI charge can carry severe consequences, from heavy fines to the suspension of your driver’s license. A central piece of evidence in many DUI cases is the blood alcohol test, which measures your blood alcohol content (BAC) to determine impairment. While these tests are often portrayed as indisputable, they are not always accurate or reliable. If you suspect your test results were flawed or improperly obtained, you may have grounds to challenge them. 

How Blood Alcohol Testing Works in Missouri

Missouri law defines a BAC of 0.08% or higher as evidence of impairment for drivers aged 21 and over. For commercial drivers, the limit is stricter at 0.04%, and for drivers under 21, a zero-tolerance policy applies, meaning even a BAC as low as 0.02% can result in penalties. Law enforcement uses various methods to measure BAC, including:

• Breath Tests: Devices like breathalyzers estimate BAC by measuring the alcohol content in a person’s breath. These are the most common tests performed during traffic stops.
• Blood Tests: Blood samples are analyzed in a laboratory to determine the exact alcohol content. This method is often used when more precise results are required.
• Urine Tests: Though less common, urine tests may be used if other methods are unavailable. However, they are considered less accurate than breath or blood tests.

Each method has its own strengths and weaknesses, and understanding how these tests function is crucial when questioning their reliability in a legal setting.

Factors That Can Affect BAC Test Accuracy

While BAC tests are designed to measure impairment, several factors can compromise their accuracy. Understanding these potential issues can provide a foundation for challenging the results. Common factors include:

• Improper Maintenance of Equipment: Breathalyzer devices require regular calibration and maintenance to ensure accuracy. If not properly maintained, these devices can produce incorrect results.
• Human Error: Errors made during the administration of tests, such as failing to follow standardized procedures, can invalidate the results.
• Environmental Factors: Substances like mouthwash, certain medications, or even exposure to chemical fumes can lead to false positives in breath tests.
• Health Conditions: Conditions such as diabetes, GERD (gastroesophageal reflux disease), or other medical issues can interfere with BAC readings, particularly in breath tests.
• Sample Contamination: Blood tests can be compromised if the sample is mishandled, stored improperly, or contaminated during the testing process.

Each of these factors represents an opportunity to question the reliability of the evidence presented against you.

Legal Strategies to Challenge BAC Results

Challenging blood alcohol test results involves analyzing the circumstances surrounding the test to identify any procedural errors or inaccuracies. Experienced attorneys can employ several strategies to dispute the validity of BAC evidence:

• Questioning Test Calibration and Maintenance: Attorneys can request records to verify whether the breathalyzer used was properly maintained and calibrated according to Missouri’s legal standards.
• Highlighting Procedural Errors: If law enforcement failed to follow required protocols during the test, such as observing a pre-test waiting period, the results might be excluded from evidence.
• Examining Chain of Custody: For blood tests, the prosecution must demonstrate that the sample was collected, transported, and stored correctly. Any lapses in this chain can cast doubt on the accuracy of the test.
• Raising Medical Defenses: Conditions like diabetes or the use of certain medications can produce skewed BAC results. These medical issues can serve as a defense to challenge the reliability of the test.
• Questioning Probable Cause: If the initial stop or arrest lacked sufficient legal justification, all evidence obtained thereafter, including BAC results, may be deemed inadmissible.

These strategies allow defendants to dispute the evidence and potentially weaken the prosecution’s case.

The Role of Errors in BAC Testing

Errors in the administration or analysis of BAC tests can significantly impact the outcome of a DUI case. For instance, breathalyzers are sensitive devices that require precise operation. If the officer administering the test deviates from established procedures, such as failing to ensure a clean breath sample or ignoring the pre-test observation period, the results can be inaccurate.

Blood tests, while generally more reliable, are not immune to mistakes. Issues such as contamination, improper storage, or mishandling of the sample can all lead to false readings. Additionally, delays in transporting the sample to a laboratory can allow fermentation to occur, artificially increasing the alcohol content.

By highlighting these errors, defendants can argue that the test results are not reliable enough to be used as evidence in court.

Why Legal Representation Matters

Successfully challenging BAC test results requires an in-depth understanding of Missouri DUI laws, as well as the technical aspects of alcohol testing. An experienced attorney can scrutinize every detail of your case, from the validity of the traffic stop to the accuracy of the testing process, to build a robust defense.

Attorneys can also work with expert witnesses to examine the testing procedures and equipment used, providing additional support for your claims. By thoroughly investigating the circumstances of your arrest and the administration of the BAC test, your attorney can identify weaknesses in the prosecution’s case and argue for reduced charges or even dismissal.

Contact Bert Fulk Today to Protect Your Rights

Facing a DUI charge can feel overwhelming, but it’s important to remember that you have the right to challenge the evidence against you. BAC test results, while often treated as definitive, are subject to error and scrutiny. If you believe your test results are inaccurate, seeking professional legal guidance is essential to protecting your rights and building a strong defense.At Bert Fulk, Attorney at Law, we specialize in DUI defense and have extensive experience challenging BAC test results. Our team understands the complexities of DUI cases and is committed to providing the aggressive representation you deserve. If you’re facing charges and have questions about the reliability of your BAC test, we can help. Contact us today to schedule a consultation and learn more about your legal options.