Breathalyzer and blood tests are often viewed as the most compelling forms of evidence in drunk driving cases. Many people assume that because these tests involve science and technology, they must be accurate and unquestionable. However, experienced DUI, DWI, OWI, OVI, and OUI attorneys know that chemical testing is far from perfect. Numerous factors can influence test results, and skilled defense lawyers routinely challenge these tests to protect their clients’ rights. Get more insights on Miami DUI lawyer.

One of the most common issues associated with breathalyzer tests is improper calibration or maintenance of the device. Breath-testing machines require regular servicing, detailed record keeping, and strict adherence to state protocols. If law enforcement fails to follow required procedures, the accuracy of the results can be compromised. Defense attorneys often request maintenance logs and calibration records to determine whether the machine was functioning properly at the time of the test. If inconsistencies or lapses are discovered, the test results may be deemed unreliable and excluded from evidence.

Human error is another factor that can lead to flawed breathalyzer results. Officers must be properly trained to administer these tests, and even small mistakes—such as failing to observe the driver for a required period before testing—can impact the outcome. Residual mouth alcohol from dental appliances, recent mouthwash use, or acid reflux can also artificially elevate breathalyzer readings. Many people are unaware that certain medical conditions can mimic high blood alcohol levels on breath tests. Skilled defense attorneys bring these issues to light to weaken the prosecution’s case.

Blood testing, while generally more accurate than breath testing, is also vulnerable to error. The process involves drawing, storing, transporting, and analyzing blood samples, often over extended periods. Any break in the chain of custody can raise questions about the integrity of the sample. Contamination, fermentation, improper storage, or mistakes at the laboratory can significantly alter results. Defense lawyers frequently examine lab certifications, technician qualifications, and testing protocols to identify weaknesses. If procedural errors are found, the credibility of the blood test can be undermined.

Another powerful defense strategy involves challenging whether law enforcement had proper legal grounds to request chemical testing in the first place. If the initial traffic stop was unlawful or the officer failed to follow implied consent rules, the test results may be suppressed entirely. Without chemical evidence, the prosecution’s case becomes much weaker.

In DUI defense, the accuracy of breathalyzer and blood tests is never assumed. Experienced attorneys understand that these tests are only as reliable as the people, procedures, and equipment behind them. By exposing flaws in testing and analysis, skilled lawyers often achieve reduced charges, dismissed cases, or favorable plea agreements for their clients.