If you've been pulled over on suspicion of driving while impaired (DWI) in Charlotte, you may be asked to submit to a chemical test to determine your blood alcohol content (BAC). In North Carolina, this typically means either a breath test, commonly known as a breathalyzer, or a blood test. While both tests serve the same purpose of measuring BAC, there are significant differences in how each test is administered, processed, and potentially challenged in court.
Our experienced Charlotte DWI defense lawyers at Browning & Long, PLLC are former prosecutors and understand the nuances of breathalyzer vs. blood tests in DWI cases. We know that the type of test used can significantly impact the strength of the prosecution's case and your available defense strategies. In this article, we'll explore the key differences between blood and breath tests, and discuss how our attorneys can challenge the accuracy and admissibility of your test results.
How Breathalyzer vs. Blood Tests in DWI Cases Are Administered in Charlotte
One of the most notable differences between breathalyzer vs. blood tests in DWI cases is how each test is administered. Here's a closer look:
Breathalyzer Tests
Breathalyzer tests are the most common type of chemical test used when people are arrested for DWI under N.C.G.S. § 20-138.1 in Charlotte. When you blow into a breathalyzer device, it measures the amount of alcohol in your breath and uses that measurement to estimate your BAC. In North Carolina, breath tests must be administered by a certified chemical analyst using an approved device and in accordance with specific procedures.
Blood Tests
Blood tests are less common in Charlotte DWI cases, but may be used in certain situations, such as when a driver is unconscious or unable to provide a breath sample. In a blood test, a blood sample is drawn and sent to a lab for analysis to determine your BAC.
Blood tests must be performed by a qualified person using sterile equipment. The blood sample must be properly stored and transported to an approved lab for testing.
DUI Test Accuracy of Breathalyzers and Breath Tests
Another key difference between breathalyzer vs. blood tests in DWI cases is their level of accuracy. While both tests are generally considered reliable, there are potential sources of error that can affect the results. Blood tests are usually more accurate. Here are some factors that can affect how accurate the test results are.
Factors Affecting Breathalyzer Test Accuracy
Breath tests can be affected by a variety of factors, including:
- Residual mouth alcohol. If you recently consumed alcohol or used mouthwash containing alcohol, it can cause an artificially high BAC reading.
- Certain medical conditions. Conditions such as acid reflux, diabetes, or medications can produce false-positive results.
- Device calibration. If the breathalyzer device is incorrectly calibrated, it can produce inaccurate readings.
- User error. Improper administration of the test by the officer can lead to unreliable results.
Factors Affecting Blood Test Accuracy
While blood tests are often considered more accurate than breath tests, they are not immune to error. Potential issues with blood tests include:
- Contamination. If the equipment used to draw the blood is not sterile, it can contaminate the sample and affect the results.
- Fermentation. If the blood sample is not properly stored or preserved, the glucose in the blood can ferment and produce alcohol, leading to an artificially high BAC reading.
- Lab error. Mistakes made by lab technicians during the testing process can produce inaccurate results.
How to Challenge Breath and Blood Tests by Raising Chain of Custody and Admissibility Issues
In addition to accuracy concerns, both blood and breath tests can be challenged based on chain of custody and admissibility issues. This is where having our knowledgeable Charlotte DWI lawyers can make a significant difference in your case.
Breath Test Challenges
Some potential challenges to the admissibility of breath test results include:
- Lack of probable cause for the stop. If the officer did not have a valid reason to pull you over in the first place, your subsequent breath test may be deemed inadmissible.
- Failure to observe the required waiting period. Before administering a breath test, officers must observe you for at least 15 minutes to ensure you do not consume anything or regurgitate, which could affect the results. Failure to adhere to this waiting period could result in the test being thrown out.
- Inadequate officer training. If the officer who administered the test was not properly trained or certified, we may be able to challenge the DUI test’s accuracy.
Blood Test Challenges
Challenges to blood test results often focus on chain of custody issues, such as:
- Improper labeling or storage of the sample. If the blood sample is not labeled correctly or stored, it can cast doubt on the reliability of the results.
- Gaps in documentation. If there are missing links in the chain of custody documentation from the time your blood is drawn until it is presented in court, it can be argued that the sample may have been tampered with or contaminated.
- Failure to preserve evidence. If the prosecution fails to preserve the blood sample for independent testing by the defense, it may be grounds for exclusion of the results.
The Importance of Experienced Legal Representation
As you can see, many potential issues can arise with blood and breath tests in Charlotte DWI cases. At Browning & Long, PLLC, our Charlotte DWI attorneys deeply understand the science behind blood and breath tests and the legal strategies to challenge their accuracy and admissibility in court. We'll thoroughly investigate the circumstances of your arrest and the testing procedures used, hire expert witnesses if necessary, and work hard to build a strong defense on your behalf.
