When your BAC (blood alcohol concentration) fluctuates during testing, question accuracy and reliability. The key defense lies in examining every step of the testing process. You need to know your rights and the limits of BAC testing.
Understanding BAC fluctuations
Your BAC can change between tests because of your metabolism, timing, or equipment. For example, if the breath test is taken too soon after drinking, alcohol in your mouth can elevate the result. Blood draws can degrade if not stored properly, altering results.
Challenging the testing procedures
You can challenge how the test was handled. Ask whether the machine was calibrated recently or whether the officer performed the required maintenance checks. Even small lapses can make the test results unreliable. Officers must calibrate breathalyzers to state standards—any deviation can help your case.
Pointing out human error or medical issues
Human mistakes and medical conditions can influence BAC readings. Did the officer properly administer the test? Was the mouthpiece contaminated? Do you have gastroesophageal reflux disease (GERD) or diabetes, which can cause false positives? Pointing to medical issues or errors in procedure can introduce reasonable doubt.
Bringing in expert analysis
Experts can analyze your case and stress test results. A qualified professional can explain that the fluctuations are signs of inaccurate testing, not your guilt. They can testify about latent effects like mouth alcohol, calibration errors, or sample storage problems. This can be compelling to judges and juries.
Building a timeline of drinking and testing
Creating a clear timeline helps show that your BAC could have spiked or dropped naturally. If multiple tests occur over time, show how your body processes alcohol. This context can weaken the prosecution’s case, especially when BAC results don’t align with your reported drinking time.
Pressuring labs through cross-examination
Science labs must follow strict protocols, from sample handling to analysis. Cross-examining lab technicians about procedures or discrepancies can expose weaknesses. If the chain of custody is broken or documentation is inconsistent, it undermines the prosecution.
A strong DUI defense focuses on errors, human factors, medical conditions, and expert testimony. When your BAC readings fluctuate significantly, you can argue that the results are unreliable. You challenge the accuracy, not your conduct.
