Challenging Breathalyzer and Blood Test Results in DWI Cases

If you’re facing DWI charges in North Carolina, the results from a breathalyzer or blood test could serve as pivotal evidence against you. However, did you know that these tests aren’t infallible? They can be challenged on various grounds, potentially turning the tide in your favor. Whether you were tested roadside or at a hospital, understanding the intricacies of these tests—and their potential flaws—is the first step in mounting a strong defense and protecting your rights. Stay with us as we delve into how these tests work and explore the options for contesting them.

Understanding Breathalyzer and Blood Tests in DWI Cases

In North Carolina, DWI charges frequently depend on the chemical analysis of blood alcohol concentration (BAC). Breathalyzer tests estimate your BAC through breath samples, whereas blood tests assess the alcohol content found in the bloodstream. Strict protocols dictated by North Carolina law govern both procedures.

Key Differences: DWI Breathalyzer vs. Blood Test 

Each type of test has its strengths and weaknesses. Understanding the differences can help your attorney build a defense tailored to the specific facts of your case.

DWI Breathalyzer Readings

Let’s look at some specifics about breathalyzers.

• Who administers. A preliminary test can be given by law enforcement officers at the scene using a portable device, but these are used only to establish probable cause for an arrest and aren’t reliable enough to be used in court. After arrest, a chemical analyst will administer the Intox EC/IR II test, which is considered reliable enough to present as evidence against you in court. 
• Where they’re used. The police can choose to administer the less reliable, portable tests roadside during a traffic stop or at a checkpoint, usually within minutes of pulling someone over. The chemical analyst administers the more reliable test at the police station.
• Things that can affect results. Mouth alcohol from recently consumed drinks or mouthwash, specific diets (like keto), medications, or medical conditions such as GERD, diabetes and others can impact the test results. Procedural errors like improper calibration or improper test administration can also alter the results, making them less reliable.
• Result reliability. Due to the things that can alter the results, breathalyzer readings may not reflect an accurate BAC. Your attorney can challenge questionable results.

How does this compare to blood tests?

DWI Blood Test Levels

Now, let’s look at the specifics of blood tests.

• Who administers. Blood draws must be conducted by trained medical personnel, such as nurses or phlebotomists.
• Where they’re given. Subjects are transported to a hospital or medical facility where trained personnel draw the blood sample, or EMTs can draw the blood at the police station if asked. Law enforcement sends the sample to a lab for analysis.
• Things that could affect results. Issues like improper handling, improper labeling, sample contamination, incorrect procedures, and expired collection kits can throw off the results of a blood test.
• Result reliability. While generally more accurate than breath tests, blood test results can be thrown out if any issues call the results into question. 

Whether you failed a breathalyzer but passed a blood test or vice versa, these results don’t always tell the whole story.

How You Can Challenge These Tests

Test results that the prosecutor presents aren’t necessarily bulletproof. Here are common strategies attorneys use to challenge breathalyzer and blood test results in DWI cases:

• Questioning qualifications—challenging whether the officer or medical person who administered the test was certified or adequately trained;
• Reviewing equipment maintenance and calibration logs—challenging whether the devices used were regularly tested for accuracy and whether they comply with The Forensic Tests for Alcohol (FTA) Branch rules;
• Challenging timing—delays between driving and testing can result in misleading BAC results;
• Investigating contamination or mishandling—blood samples must be taken in a way that avoids contamination, and personnel must follow strict chain of custody rules; and
• Presenting scientific evidence—such as expert testimony about conditions that can skew test results.

In many cases, these challenges can result in reduced charges, case dismissal, or the suppression of critical evidence.

Why Your Choice of Defense Counsel Matters

Breathalyzer and blood test results are often central to a DWI case, but they are not always reliable and are certainly not immune to legal challenges. If you have been charged with DWI in Beaufort or Carteret County, you deserve a legal team that understands the local court system and knows how to carefully examine every detail of the state’s case.

At Tetterton Law Firm, PLLC, we bring together decades of criminal law experience and a deep commitment to serving the Beaufort community. We’re led by Attorney Joshua Tetterton, a lifelong North Carolinian with a strong track record defending DWI and traffic cases throughout Carteret County. Our hands-on approach means your case won’t be passed off to an assistant; our lawyers analyze every angle to give you the most vigorous defense possible. Call us today for a confidential consultation and find out how we can help challenge the evidence and protect your future.

FAQs

Can I Refuse a Breathalyzer or Blood Test If I’m Pulled Over for DWI?

Yes, you can refuse the test. However, under North Carolina’s implied consent law, refusing a chemical test results in an automatic one-year license suspension, regardless of whether you are convicted of DWI.

What Happens If I Refuse a Breathalyzer or Blood Test in a DWI Case?

Along with losing your license for a year, your refusal can be presented in court as evidence of potential impairment.

How Accurate Are DWI Breath Test Results?

Breath tests are designed to estimate BAC but can be affected by factors like calibration, environmental conditions, and even medical issues such as acid reflux.

Can Breathalyzer Results Be Challenged in Court?

Yes. Common challenges include improper administration, expired calibration, lack of officer certification, and external factors that might have affected the test.

How Can Improper Handling or Storage of a Blood Sample Affect DWI Cases?

Blood samples not properly stored or tracked can become contaminated or degraded, potentially rendering the results inadmissible in court.