Breath tests are often the most damaging piece of evidence in a DUI case. If a defendant’s blood alcohol content (BAC) is over the legal limit, they are considered under the influence of alcohol, regardless of their behavior. There are possible defenses to breathalyzer test results, however, such as rising blood alcohol or a testing machine malfunction. An experienced attorney could explain various DUI breath test defenses and how they could help a defendant avoid serious penalties.

Rising Blood Alcohol

Rising blood alcohol is an increase in someone’s BAC over a certain period of time. In some cases, rising blood alcohol could be a valid defense for DUI. The basic argument is that the individual’s BAC at the time of testing was higher than at the time of driving.

A person’s blood-alcohol level will peak at a certain time, depending on what type of drink they consumed and how much they consumed. Typically, a person’s body absorbs alcohol within approximately 30 minutes of consumption. This time period can vary depending on the number of drinks, the types of drinks, and how quickly the individual consumes them.

Preparing a defense involving rising blood alcohol level requires a certain level of understanding about science. A lawyer may bring in an expert toxicologist to help evaluate whether someone’s blood alcohol was possibly under the legal limit when they operated the motor vehicle.

Breath Test Errors

A DUI lawyer in Charleston might use a potential error in a person’s breath test as a defense strategy. In some cases, there may be audio indicators that a machine is not working properly, or there may be evidence of a malfunction. Proper DUI testing requires the machine operator to follow strict protocols, and a failure to do so could make the test results invalid.


For a breath test to be accurate, certain parameters must be met, including the temperature of the individual’s breath. A very high or low temperature can alter breath test results.

Alcohol-Based Products

Certain products, like cough syrup or mouthwash, contain alcohol. If someone uses one of these products, alcohol lingering in their mouth could cause an overly high BAC reading.

Teeth and Oral Hygiene

The condition of a person’s teeth can affect a breath test. For example, people who wear dentures or have a cavity may have alcohol trapped inside their mouths. This alcohol could cause a breathalyzer test to be inaccurate.

Let a Charleston Lawyer Defend against DUI Breath Test Results

While breath tests are an important piece of evidence when prosecuting DUIs in Charleston, there may be powerful defenses available. These machines are not foolproof, and something as simple as a breach of the testing protocol could make the BAC results unreliable.

Building a credible defense against DUI breath test results requires close attention to detail and a careful analysis of the facts. A skilled attorney could scrutinize all of the evidence against you and work to exploit any weaknesses in the prosecution’s case. To schedule a consultation, call now.