Limitations of DUI BAC (Breath Testing)

If you are arrested for a DUI in Maryland, the chances are good that the police gave you a breathalyzer test in order measure your blood alcohol content (BAC) level. The maximum legal BAC level in the state is .08 percent, although you can be arrested for DUI if your BAC is lower than .08 percent and you exhibit signs of physical impairment. If you are arrested, you will need an experienced Maryland DUI defense lawyer to protect your rights in court.

Interestingly, most people (including judges) do not know that DUI breath testing is fraught with potential errors. The machines themselves can malfunction for a number of reasons and a wide variety of factors can impact the readings and artificially inflate them.

Changes in breathing patterns can affect breath results. For example, if an accused hyperventilates or exhales heavily prior to submitting to DUI breath testing, their BAC levels may drop considerably. On the other hand, if they hold their breath (as the police will instruct), their BAC level will increase.

Machine readings can vary about 15 percent or more. Almost one-fourth of individuals have a higher BAC reading than their actual blood-alcohol level, which means the police arrest more people for DUI. The breathalyzer needs to be regularly calibrated to a preset, standardized level. Machines should be maintained and calibrated once every six months in order to ensure they are functioning properly. Failure to maintain equipment properly results in faulty readings.

Women have a lower blood volume than do men. Some machines are set to measure BAC at a specific blood reading. This can artificially inflate a woman’s BAC level if they have a lower blood volume and usually affects women more often than men.

Temperature of the outside air or of the subject’s breath can affect their performance and potential results. Other substances, such as lacquer, cleaning fluids, paint remover and gasoline and its additives, can also distort test results. If you were accused of a DUI after working around any of these chemicals or if the temperature was extremely high or extremely cold, call our Maryland DUI defense team to evaluate your case.

Some older breathalyzers do not differentiate between the ethanol in an alcohol drink and other similar substances. This can result in false positive readings in DUI breath testing. Health conditions can also affect BAC levels. For example, a dieter or a diabetic often has acetone levels that are significantly increased. Older breath testers will not properly differentiate between a person’s acetone level and their ethanol level. A breathalyzer can register alcohol from the mouth, throat or stomach instead of from the lungs. An inaccurate reading will significantly change a BAC level.

Most often, mouth alcohol is a result of belching or burping. Acid reflux is another common problem that can increase breathalyzer results. The excess gases in the system can stay in the mouth and cause a false high reading. Law enforcement personnel should observe suspects prior to taking a BAC in order to validate the test specimen. Other causes of mouth alcohol include dentures, periodontal disease, mouthwash and intense kissing with an intoxicated person. If you have any medical conditions, you will need to contact a Maryland DUI defense lawyer for advice.

Once a person finishes drinking, alcohol absorption continues for between 20 to 150 minutes, depending on the amount of food eaten. This absorption occurs at different and uneven rates and affects certain parts of the body differently than others. The results might be inaccurate if DUI breath testing in Maryland is administered during this window of time.

Most people assume that law enforcement knows how to properly conduct field and breath test; however, that is not always the case, and law enforcement is almost always biased in terms of wanting that conviction. Thus, if arrested for DUI, try our DUI Defense team and let us show you what we can do.

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